Journal articles on the topic 'Eagles'
To see the other types of publications on this topic, follow the link: Eagles.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Eagles.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Annisa, Mariana Fikriyanti, and Susanti Withaningsih. "DNA sexing for gender determination of Changeable Hawk-Eagle (Nisaetus cirrhatus, Gmelin, 1788)." E3S Web of Conferences 249 (2021): 03012. http://dx.doi.org/10.1051/e3sconf/202124903012.
Full textAbstract:
The Changeable hawk-eagle (Brontok eagle) is a protected bird species. It is one of the most frequently hunted and traded birds in Indonesia. The processes of being traded changes this bird natural behaviour. Therefore, a rehabilitation effort to return the eagle’s behaviour to conform to its natural habits is needed. The ultimate goal of rehabilitation is to release the changeable hawk-eagle back into its natural habitat. In conservation and breeding programs, efforts to determine the sex of eagles to be released are very important to help increase the population of changeable hawk-eagles in their habitat by looking at the sex ratio. At the present, sex determination at the Kamojang Conservation Eagle Center (Pusat Konservasi Elang Kamojang or PKEK) uses the morphometric method. This research used the DNA sexing method with primers 2550F and 2718R to determine the sex of Changeable hawk-eagles in PKEK by extracting DNA from blood samples of 30 eagles. Comparison of DNA sexing results and morphometric data showed differences. This proves that DNA sexing, is suitable in determining changeable hawk-eagles’ sex.
2
Mayrose, A. "Does the Release of Bonelli’s Eagles from Captive Breeding Nucleus Contribute to Population Rehabilitation?" Raptors Conservation, no. 2 (2023): 78–79. http://dx.doi.org/10.19074/1814-8654-2023-2-78-79.
Full textAbstract:
During the late 1960s, the Bonelli’s Eagle (Aquila fasciata) population in Israel was brought to the brink of extinction, due to a combination of factors. A rehabilitation program set in 2000 included few measures, among them the release of eaglets from a captive breeding nucleus, producing two to seven eaglets yearly. In recent years there is an apparent increase in the number of Bonelli’s Eagle pairs breeding in the wild, including the reoccupation of territories that were abandoned for many years. Yet, there is only little evidence for the recruitment of captive-born eagles into the wild population, and their contribution to its growth is unclear. These subjects are now being examined by a telemetry study, comparing dispersal patterns and survival rates of captive versus nature hatched eagles. The results from the first five years of study show significant differences between these two groups, with captive hatched eagles dispersing much farther away from their natal site compared to the dispersal of wild eagles. The different dispersal patterns may be the reason for the lower survival rates exhibited by the captive hatched eagles, as many of them wander to neighboring countries where they are subjected to shooting and trapping. Moreover, these birds also have a higher tendency to being electrocuted on power lines. Genetic analysis and alteration of the releasing methods are being used in order to check whether the different movement and behavior attributes of the captive-hatched eagles are linked to genetic properties or behaviorally mechanisms during their growth.
3
Dixon, A., N. Batbayar, B. Bold, G. Purev-Ochir, A. Gunga, and M. Virani. "Electrocution of Eagles in Mongolia." Raptors Conservation, no. 2 (2023): 400–402. http://dx.doi.org/10.19074/1814-8654-2023-2-400-402.
Full textAbstract:
Steppe Eagles (Aquila nipalensis) and Golden Eagles (Aquila chrysaetos) are species of conservation and cultural importance in Mongolia. Electrocution at electricity distribution lines is a threat faced by both species across Central Asia. We present the results of power line surveys conducted in the Mongolian steppe region to elucidate temporal patterns of electrocution and specific danger points on power poles for eagles. There was spatial and temporal variation in electrocution rates for Steppe Eagles and Golden Eagles. Autumn surveys across Mongolia recorded the electrocuted carcasses of 18 Steppe Eagles and 9 Golden Eagles. The distribution of electrocutions revealed that Steppe Eagles are mainly killed at power lines in the central steppe zone; in contrast, only Golden Eagles were found at power lines in the southern ‘gobi’ desert zone. Daily surveys conducted for a year at a single power line in the eastern steppe detected 8 Golden Eagles and 6 Steppe Eagles. All Steppe Eagle electrocutions occurred between April and September as they are predominantly summer visitors in Mongolia, whereas six of the eight Golden Eagle electrocutions occurred in winter indicating that Golden Eagles can range over predominantly flat, open steppe landscapes at this time. Significantly more electrocutions occurred at poles with no crossarm mitigation compared to poles with deflectors, deterrents or covers, indicating that mitigation on the crossarm can reduce eagle electrocution rates. Furthermore, the absence of eagle carcasses at poles with crossarm mitigation suggests that crossarms are the main site of electrocution for eagles in Mongolia. Country-scale retrofitting of insulation to crossarms and pole tops significantly reduced eagle electrocution events.
4
Sidiropoulos, Lavrentis, D. Philip Whitfield, Christos Astaras, Dimitris Vasilakis, Haralambos Alivizatos, and Vassiliki Kati. "Pronounced Seasonal Diet Diversity Expansion of Golden Eagles (Aquila chrysaetos) in Northern Greece during the Non-Breeding Season: The Role of Tortoises." Diversity 14, no. 2 (February 14, 2022): 135. http://dx.doi.org/10.3390/d14020135.
Full textAbstract:
Golden Eagles are resident in Greece and known to feed mainly on tortoises when breeding. However, information on alternative prey is scarce, especially during the tortoise brumation, that roughly coincides with the eagles’ non-breeding season. We analyzed 827 prey items collected from 12 territories over five territory years and 84 records of eagles hunting or feeding behavior. Tortoises dominated the breeding season diet (71% of prey categories on average) and over half of all hunting/feeding observations. While no spatial structure was evident, habitat variables such as forest canopy cover were important associates in golden eagle diet seasonally. A significant seasonal pattern emerged in diet diversity, using a subset of six territories with at least 10 samples per season. Eagles shifted from a narrow, reptile- based breeding season diet dominated by tortoises to a broader non-breeding season diet, that included more carrion, mammals and birds. Breeding season specialization on ectothermic prey is a trait usually associated with migratory raptors in the Western Palearctic. The observed dietary diversity expansion accompanied by residency in the absence of ectothermic prey, highlights the adaptability of the golden eagle, a generalist predator. Tortoise populations in Greece are of conservation concern and land use changes as well as climate change, such as development and land abandonment may increase the prevalence of catastrophic megafires, exacerbating the threats to the golden eagle’s main prey when breeding. We discuss this and other diet related conservation implications for the species in northern Greece.
5
Harvey, C. J., T. P. Good, and S. F. Pearson. "Top–down influence of resident and overwintering Bald Eagles (Haliaeetus leucocephalus) in a model marine ecosystem." Canadian Journal of Zoology 90, no. 7 (July 2012): 903–14. http://dx.doi.org/10.1139/z2012-059.
Full textAbstract:
Conservation of predators presents challenges when predators affect prey populations that provide ecosystem services. Near Puget Sound, resident and overwintering populations of Bald Eagle ( Haliaeetus leucocephalus (L., 1766)) have expanded in recent decades. We modeled the potential impact of Bald Eagles on marine food-web structure. Bald Eagles caused trophic cascade dynamics through mid-level predators (seabirds) to lower trophic levels (fishes, benthic invertebrates), particularly when seabirds were more abundant in eagle diets. Resident Bald Eagles affected food-web structure more than overwintering eagles, despite the latters’ greater abundance. Predator avoidance behavior by nearshore diving birds and herbivorous birds exacerbated trophic cascade effects, but only in a narrow range of species. Variability in the number of overwintering Bald Eagles, which come to the area to feed on salmon carcasses (primarily chum salmon, Oncorhynchus keta (Walbaum in Artedi, 1792)), had little effect on the food web. Our results indicate that Bald Eagles are important to marine food-web structure, owing to their high consumption rates and the high consumption rates of their seabird prey, but uncertainty about eagle diets limits our full understanding of their impact. In systems where Bald Eagles affect large seabird breeding colonies, their role in food-web structure is likely greater.
6
Jones, I. M., R. W. Butler, and R. C. Ydenberg. "Recent switch by the Great Blue Heron Ardea herodias fannini in the Pacific northwest to associative nesting with Bald Eagles (Haliaeetus leucocephalus) to gain predator protection." Canadian Journal of Zoology 91, no. 7 (July 2013): 489–95. http://dx.doi.org/10.1139/cjz-2012-0323.
Full textAbstract:
The Great Blue Heron Ardea herodias fannini Chapman, 1901 in the Pacific northwest appears to have modified nesting behaviour in response to the strong recent recovery of the Bald Eagle (Haliaeetus leucocephalus (L., 1766)) population. Previously undescribed, herons now often nest in close association with some breeding eagles, even though eagles depredate heron nestlings, are implicated in the recent reproductive decline of herons, and may induce abandonment of heron breeding colonies. We tested the hypothesis that breeding herons gain protection from the territorial behaviour of eagles. Natural observations and simulated incursions showed that nesting eagles actively repel other eagles within at least 250 m around the nest site, thereby establishing a relatively safe place for herons to nest. Surveys showed that 70% of heron nests and 19% of heron colonies were located within 200 m of eagle nests with high reproductive success. These herons had greater reproductive success than those nesting far from eagle nests.
7
LERNER, HEATHER, LES CHRISTIDIS, ANITA GAMAUF, CAROLE GRIFFITHS, ELISABETH HARING, CHRISTOPHER J. HUDDLESTON, SONIA KABRA, et al. "Phylogeny and new taxonomy of the Booted Eagles (Accipitriformes: Aquilinae)." Zootaxa 4216, no. 4 (January 9, 2017): 301. http://dx.doi.org/10.11646/zootaxa.4216.4.1.
Full textAbstract:
We present a phylogeny of all booted eagles (38 extant and one extinct species) based on analysis of published sequences from seven loci. We find molecular support for five major clades within the booted eagles: Nisaetus (10 species), Spizaetus (4 species), Clanga (3 species), Hieraaetus (6 species) and Aquila (11 species), requiring generic changes for 14 taxa. Additionally, we recommend that the Long-crested Eagle (Lophaetus occipitalis) and the Black Eagle (Ictinaetus malaiensis) remain in their monotypic genera, due to their distinctive morphology. We apply the recently resurrected genus Clanga for the spotted eagles (previously Aquila spp.) to resolve the paraphyly of the genus Aquila such that the clade including the Booted Eagle (H. pennatus), Little Eagle (H. morphnoides), Pygmy Eagle (H. weiskei), Ayres’s Eagle (H. ayresii) and Wahlberg’s Eagle (H. wahlbergi) can remain in the genus Hieraaetus. The Rufous-bellied Eagle should be retained in the genus Lophotriorchis. For consistency in English names, we recommend that the term “hawk-eagles” be used only for the species in the genera Nisaetus and Spizaetus. We suggest following new or modified English names: Cassin’s Eagle (Aquila africana), Bonaparte’s Eagle (A. spilogaster), Ayres’s Eagle (Hieraaetus ayresii), and Black-and-chestnut Hawk-Eagle (Spizaetus isidori).
8
Supratman, Lilis, Rita Istiana, Rania Dhania, and Hafidz Zufitrianto. "Behavioral Study of Crested Serpent-eagle (Spilornis cheela) as Conservation Education in Pusat Suaka Satwa Elang Jawa." Journal of Tropical Ethnobiology 6, no. 1 (January 31, 2023): 21–30. http://dx.doi.org/10.46359/jte.v6i1.163.
Full textAbstract:
One of the raptors commonly found in Indonesian forests is Crested Serpent-eagle (Spilornis cheela). However, its population in its natural habitat is hampered due to habitat loss, illegal trade, and hunted for pets. Pusat Suaka Satwa Elang Jawa (PSSEJ) is a rehabilitation center specialized for mountain eagles, focused on rehabilitation and releasing the eagles to their original habitat. Eagles taken care of in PSSEJ were handed over from the public, Nature Conservation Agency (BKSDA), or other conservation institutions. Other than as a rehabilitation center, PSSEJ became an education and conservation center for raptors as a continuous effort to manage natural resources and biodiversity. Crested Serpent-eagle that are not eligible to be released based on observation in the rehabilitation stage would be kept in a display cage. The display cage is purposed as a conservation education facility for PSSEJ visitors. This study aimed to find daily activity frequency of Crested Serpent-eagle in PSSEJ display cage as information that supports conservation education. The observation was conducted for five days from 08.00 am - 04.00 pm using ad libitum sampling and focal animal sampling methods. Based on the results, it could be concluded that the biggest percentage of Crested Serpent-eagle’s daily activity in the display cage is perching at 71.6%. This percentage is similar to the percentage of eagle perching activity in nature. Although the percentage of its activity is similar, the Crested Serpent-eagle in this study has a very small possibility of being released into the wild because, after more than one year of rehabilitation, its dependency on humans has not disappeared.
9
Ostashchenko, A. N., and A. Yu Zakharov. "About the population of the Golden Eagle in the Eastern part of the Kyrgyz Range, Northern Tian Shan, Kyrgyzstan." Raptors Conservation, no. 2 (2023): 22–25. http://dx.doi.org/10.19074/1814-8654-2023-2-22-25.
Full textAbstract:
The material for this paper is based on occasional observations of the Golden Eagle (Aquila chrysaetos) over a 30-year period and on breeding data collected from March 21 to April 14, and from May 21 to June 14, 2019, in the foothills and middle mountains of the northern macro slope of the Kyrgyz Range, from the Boom Valley in the east to the Kara-Balta area in the west. This territory is stretching on 170 km. The main goal of the fieldwork was to search for Saker Falcon’s (Falco cherrug) nests, thus information about the Golden Eagle’s nests was collected mostly occasionally. Nevertheless, these data objectively reflect the current state of the population. During the survey period, six active nests of the Golden Eagle were discovered. One nest was located on a rock ledge, two nests were built within niches in conglomerate cliffs, and three nests were found on clay cliffs. In the latter case, the nests were built on the basis of shrubs growing on the cliffs. Usually, the contents of the nests were not observed. Only in one nest an egg was seen on March 26, and on May 23 the nest contained a fledgling with growing flight feathers. In total, during the field trip, 11 adult and two juvenile Golden Eagles were encountered, excluding territorial birds observed near the nests. The Golden Eagle is present in the Kyrgyz Range all year round. It appears that a pair consistently maintains its nesting territory, driving all other large eagles away. For instance, on December 3, 2018, in the foothills of the Kyrgyz Range, we observed two Golden Eagles relentlessly chase and attack an Imperial Eagle (Aquila heliaca). Breeding displays were observed near the Orto-Tokoy Reservoir on January 22, 2010. Young eagles spend the winter with their parents, who continue to feed them occasionally. In various locations within the Tien Shan range, groups of three birds, including one juvenile, are encountered throughout the winter. Presumably, during the incubation period, parents drive young birds away from themselves, at least from the vicinity of the breeding territory. For instance, on April 7, 2019, in the Beyisheke area, a pair of adults persistently chased a juvenile away from their nest. However, even during this time, it is possible to observe both adult and young Golden Eagles soaring together. Actually, the main mystery of the ecology of Golden Eagles nesting in the foothills is the structure of their spring-summer diet. There are no marmots (Marmota sp.) here, the desert hare (Lepus tibetanus) is rare in most of the area, as well as the chukar (Alectoris chukar) and the pheasant (Phasianus colchicus). Perhaps snakes play a significant role in its summer diet, since we have seen Golden Eagles carrying a snake several times. The earliest case of carrying a snake was noted as early as March 21. The local people’s attitude towards this species is mostly favorable. Three nests were located near roads and were clearly visible from them. Two nests were situated no more than a kilometer away from residential livestock enclosures, where domestic chickens and turkeys were kept alongside sheep. However, Golden Eagles do not attack domestic birds or lambs. This behavior allows them to peacefully coexist with livestock farmers for many years. Generally, the human attitude towards the Golden Eagle in the Kyrgyz Range is mostly neutral. Occasionally, it is kept for falconry purposes, but there are few enthusiasts left, and nowadays it is more of a show than a substantial practice. As a result, Golden Eagle’s population is not significantly impacted by falconers. The trend of making stuffed animals, which was very popular in the late 20th and early 21st centuries has almost disappeared. Occasionally, Golden Eagles die in traps set on other animals. There is a known case of a car accident with a Golden Eagle in the Boom Valley. As a result, the bird lost its sight. In May 2019, a dried-up carcass of a Golden Eagle was found beneath the aerial power line. Upon examination, it was discovered that half of its wing was severed with a very clean cut along the ulna and radius bones. This undoubtedly indicates a high speed collision. Most likely, the bird dived for prey and did not notice a conductor at least 10 centimeters thick against the background of the mountains. In total, the number of discovered nests, their location in areas of high human activity, and the attitude of the local population are driving us to the conclusion that the population of the Golden Eagle in the eastern part of the northern macro slope of the Kyrgyz Range is in a favorable state.
10
Debus, S. J. S., Jerry Olsen, Susan Trost, and Esteban Fuentes. "Breeding diets of the Little Eagle Hieraaetus morphnoides and Wedge-tailed Eagle Aquila audax in the Australian Capital Territory in 2011–2019." Australian Field Ornithology 38 (2021): 19–28. http://dx.doi.org/10.20938/afo38019028.
Full textAbstract:
The diets of the Little Eagle Hieraaetus morphnoides and Wedge-tailed Eagle Aquila audax breeding sympatrically in the Australian Capital Territory during 2011–2019 were compared by analysis of pellets and prey remains (six Little Eagle territories and 13 Wedge-tailed Eagle territories; 69 and 49 collections for a total of 232 and 256 prey items, respectively). Little Eagles took 33% mammals (29% European Rabbits Oryctolagus cuniculus), 44% birds, 6% reptiles and 17% insects by number, and 65% mammals (62% Rabbits), 27% birds, 8% reptiles and <1% insects by biomass. Wedge-tailed Eagles took 59% mammals (23% Rabbits and 19% macropods), 38% birds, 1% reptiles, <1% fish and 1% insects by number, and 89% mammals (20% Rabbits, 38% macropods), 10% birds, and <1% reptiles, fish and insects by biomass. Indices of dietary diversity (Shannon Index and Standardised Food Niche Breadth) were 2.57 vs 3.07 and 0.19 vs 0.24, respectively; Geometric Mean Prey Weights (GMPW) were 164 vs 1392 g, but discounting a biased sample of insects in many pellets from two fledglings, Little Eagle GMPW was more like 340 g. Dietary proportions and some metrics for both species appear to have changed little since the preceding decade, although Wedge-tailed Eagle dietary diversity increased slightly and dietary overlap (80%) increased greatly, concomitantly with some pairs of Wedge-tailed Eagles replacing pairs of Little Eagles. Intraguild predation occurred, including Wedge-tailed Eagle predation on Little Eagles.
11
Karyakin, Igor V., Elvira G. Nikolenko, Elena P. Shnayder, Ludmila S. Zinevich, Genriyetta I. Pulikova, Natalya G. Andreyenkova, Kordian Bartoszuk, Márton Horváth, Tibor Juhász, and Matyas Prommer. "Wind power development in Eastern Kazakhstan threatens migration of eagles." Raptors Conservation, no. 43 (December 31, 2021): 108–213. http://dx.doi.org/10.19074/1814-8654-2021-43-108-213.
Full textAbstract:
On the basis of data obtained from ARGOS/GPS and GPS/GSM tracking of 34 eagles (4 Steppe Eagles (Aquila nipalensis) from Central KZ, 1 Steppe Eagle from Southern Ural region, 22 Steppe Eagles, 5 Eastern Imperial Eagles (Aquila heliaca) from the ASR and 2 Greater Spotted Eagles (Aquila clanga) from the from the Altai-Sayan Ecoregion), we have defined the main flyways, terms, and other parameters of migration of eagles through Eastern Kazakhstan. We have outlined the borders of the migration corridor and estimate the number of migrants passing through it. The study highlights the importance of the Karatau ridge for eagles from the vast territories of Russia and Kazakhstan. But we are also concerned about the development of wind farms with horizontal-axis wind turbines that expose ultimate danger for raptors in the Karatau migration corridor. One of them already exists – the Zhanatas Wind-Power Station. Here we calculated the possible negative impact on the eagle population from the existing and projected wind farms of the Karatau ridge and give our recommendations for neutralizing the damage from the development of the electric power industry in Karatau.
12
Olsen, Jerry, Brian Cooke, Susan Trost, and David Judge. "Is wedge-tailed eagle, Aquila audax, survival and breeding success closely linked to the abundance of European rabbits, Oryctolagus cuniculus?" Wildlife Research 41, no. 2 (2014): 95. http://dx.doi.org/10.1071/wr14033.
Full textAbstract:
Context Some ecologists argue that nesting success and abundance of wedge-tailed eagles (Aquila audax) are strongly linked to the abundance of introduced wild rabbits (Oryctolagus cuniculus). Consequently, concerns were expressed about eagle population viability when the biological control agent rabbit haemorrhagic disease virus (RHDV) heavily reduced rabbit numbers. However, observations following the spread of rabbit haemorrhagic disease (RHD) in Australia and Spain (where Aquila adalberti is an equivalent of A. audax) question this assertion. Eagle numbers did not fall even though rabbits declined regionally by up to 90% in both countries. Aims To reconsider the assumption of a strong link between rabbit abundance and wedge-tailed eagle breeding and population maintenance. Dispelling misconceptions, if any, about the eagles’ dependence on rabbits would benefit the future management of both eagles and rabbits. Methods We reviewed the literature associated with claims that eagles were heavily dependent on rabbits and asked whether these views could be substantiated given the lack of changes in eagle abundance following the spread of RHD. Data on eagle egg-clutch size and nesting success were also reviewed. Conclusions There is little evidence that eagles depend heavily on rabbits as prey. Instead, as rabbits decline, more kangaroos, reptiles and birds are eaten, partly because more native prey becomes available. Eagles have a high proportion of rabbits in their diets mainly where degradation of natural ecosystems, including that caused by rabbits, results in native prey being rare or unavailable. There has been minimal variation in average clutch size following major perturbations in rabbit population size. Implications Rather than perpetuating the idea that high populations of rabbits are needed for wedge-tailed eagle conservation, resources would be better re-directed into understanding continental-scale eagle population dynamics. This would provide a more rational framework to assist decisions on future biological control agents for rabbits.
13
Trope, Megan. "Grey Snow Eagle House: A Partner in Conservation of Eagles." Wildlife Rehabilitation Bulletin 30, no. 1 (June 30, 2012): 31–33. http://dx.doi.org/10.53607/wrb.v30.60.
Full textAbstract:
The Grey Snow Eagle House provides rehabilitative care for injured eagles and permanently houses non–releasable eagles at the facility. Since not all rehabilitators are familiar with the facility and some rehabilitators may have an eagle US Fish & Wildlife Service has instructed go to the facility, information on the Grey Snow Eagle House is provided in this paper for a better understanding.
14
Demerdzhiev, D. A., D. D. Dobrev, Z. N. Boev, N. P. Nedyalkov, A. G. Delchev, S. A. Stoychev, and T. H. Petrov. "Grassland Alterations Do Not Affect Breeding Success, But Lead to Dietary Shifts of Eastern Imperial Eagle, a Top Predator: a Case of Successful Adaptation." Raptors Conservation, no. 2 (2023): 290–94. http://dx.doi.org/10.19074/1814-8654-2023-2-290-294.
Full textAbstract:
Habitat transformation is identified as a global threat to biodiversity, affecting threatened raptors. In our study area, habitat change dramatically affected permanent grasslands, shrinking their availability. As we expected, the decrease in share of grasslands in eagles’ territories significantly affected occupancy rate, but not productivity: we found that occupancy rate decreased significantly, while productivity showed no trend. Understanding the adaptive capacity of top predators and how they respond to shifts in prey abundance and availability is crucial for their conservation. We investigated the diet pattern of the endangered Eastern Imperial Eagle (Aquila heliaca) facing long-term and large-scale changes. We studied the abundance variation of its profitable prey, European Souslik (Spermophilus citellus), and how it reflected on eagle population trajectories in a regional and temporal context. We found a significant diet alteration expressed in large decrease of brown hare (β2=-0.83), poultry (β2=-0.81), gulls (β2=-0.71), and water birds (β2=-0.57) and an obvious increase of northern white-breasted hedgehog (β2=0.61) and doves (β2=0.60). Raptors, including owls, raised their share among the prey (β2=0.44), but white stork and different reptiles supplied more biomass. Abundance of European souslik decreased through the studied periods (adjusted R2=0.25, p<0.001), which accounted for the lower proportion of this prey in the eagle’s diet. Nevertheless, the eagle population successfully adapted and significantly increased (β2=0.97) in most of its distribution area. The trophic strategy used by this top predator related to opportunistic foraging represents an ecological advantage that allows the species to adapt to different habitats and guarantees its future. In addition, we assessed whether human-driven habitat alterations mediated dietary shifts of the Eastern imperial eagle. Following a bottom-up conception (before–after), we evaluated the effect of grassland change on the eagle’s dietary shift and breeding success. Land use patterns underwent a significant transformation over the study period, creating a large decrease in grasslands (on average, 25.79% loss in grasslands on eagle territories). Habitat alteration mediated dietary shifts, but had no reproductive consequences for eagles. Eagles became 1.90 times more likely to predate on northern white-breasted hedgehog and 1.62 times more likely to forage on white stork in the period after grassland alteration. The share of land tortoises as eagle’s prey also increased, and they were 4.04 times more likely to be predated on in the years after transformation. Conversely, brown hare was 0.51 times less likely to be consumed in the grassland loss period, while this likelihood was 0.54 times lower for rodents and 0.64 times lower for the European souslik. Doves, meanwhile, were 2.73 times more likely to be predated on in the years following grassland destruction. We found that the presence and biomass of songbirds and European Souslik correlated negatively with the breeding success of eagles, while the White Stork’s (Ciconia ciconia) presence and biomass resulted in more progeny. Diet diversity did not have an effect on the eagle’s reproductive success. The responses of the eagles may vary across territories, depending on how they rank their prey, as the territory effect was a powerful factor shaping dietary shifts for this top predator. Our results offer new evidence of the link between habitat alteration, dietary shifts, and reproductive success, contributing to our understanding of the enigmatic mechanism, through which an apex predator successfully adapts to large-scale land use pattern transformation by increasing dietary specialization. We recommend restoration of habitat complexity, including preservation of field margins, grassland patches with scattered small shrub formations, and grassland margins between medium-sized arable lands, promotion of measures for traditional grassland management through gradual grazing, and a ban on the use of shredders.
15
Niedringhaus, Kevin D., Nicole M. Nemeth, Samantha Gibbs, Jared Zimmerman, Lisa Shender, Kate Slankard, Heather Fenton, et al. "Anticoagulant rodenticide exposure and toxicosis in bald eagles (Haliaeetus leucocephalus) and golden eagles (Aquila chrysaetos) in the United States." PLOS ONE 16, no. 4 (April 7, 2021): e0246134. http://dx.doi.org/10.1371/journal.pone.0246134.
Full textAbstract:
Raptors, including eagles, are geographically widespread and sit atop the food chain, thereby serving an important role in maintaining ecosystem balance. After facing population declines associated with exposure to organochlorine insecticides such as dichlorodiphenyltrichloroethane (DDT), bald eagles (Haliaeetus leucocephalus) have recovered from the brink of extinction. However, both bald and golden eagles (Aquila chrysaetos) are exposed to a variety of other toxic compounds in the environment that could have population impacts. Few studies have focused on anticoagulant rodenticide (AR) exposure in eagles. Therefore, the purpose of this study was to determine the types of ARs that eagles are exposed to in the USA and better define the extent of toxicosis (i.e., fatal illness due to compound exposure). Diagnostic case records from bald and golden eagles submitted to the Southeastern Cooperative Wildlife Disease Study (University of Georgia) 2014 through 2018 were reviewed. Overall, 303 eagles were examined, and the livers from 116 bald eagles and 17 golden eagles were tested for ARs. The percentage of AR exposure (i.e., detectable levels but not associated with mortality) in eagles was high; ARs were detected in 109 (82%) eagles, including 96 (83%) bald eagles and 13 (77%) golden eagles. Anticoagulant rodenticide toxicosis was determined to be the cause of mortality in 12 (4%) of the 303 eagles examined, including 11 bald eagles and 1 golden eagle. Six different AR compounds were detected in these eagles, with brodifacoum and bromadiolone most frequently detected (81% and 25% of eagles tested, respectively). These results suggest that some ARs, most notably brodifacoum, are widespread in the environment and are commonly consumed by eagles. This highlights the need for research to understand the pathways of AR exposure in eagles, which may help inform policy and regulatory actions to mitigate AR exposure risk.
16
Bekmansurov, Rinur H., Igor V. Karyakin, and Elena P. Shnayder. "On eastern imperial eagle (Aquila heliaca) breeding in atypical habitat under competitive conditions with other eagle species." Slovak Raptor Journal 9, no. 1 (June 30, 2015): 95–104. http://dx.doi.org/10.1515/srj-2015-0007.
Full textAbstract:
Abstract In the paper we describe two cases of eastern imperial eagle breeding in the former nests of greater spotted eagle and white-tailed eagle observed in the Tatarstan Republic, Russia. In both cases, eastern imperial eagles occupied non-favourable habitats they never used before - a vast alder forest in the wetlands and an island in a reservoir. The possible reasons that made the eagles expand their breeding ranges in the Volga region ofRussia are discussed in this paper
17
Demerdzhiev, Dimitar, Ivaylo Angelov, and Dobromir Dobrev. "Foraging Patterns of Non-Territorial Eastern Imperial Eagle (Aquila heliaca): A Case of Successful Adaptation." Diversity 14, no. 12 (December 2, 2022): 1060. http://dx.doi.org/10.3390/d14121060.
Full textAbstract:
The Optimal Foraging Theory predicts that, to maximize fitness, animals adapt their foraging strategy that provides the most benefit for the lowest cost, maximizing the net energy gained. While the diet of many breeding raptor populations is well known, studies on the foraging patterns of non-territorial birds of prey (floaters) are scarce. In this study, we examined the foraging pattern of non-territorial Eastern Imperial Eagle, scrutinizing different aspects of its feeding ecology and behavior. We built a simple model of the optimal foraging strategy of floater eagles including the success of foraging as a currency as well as environmental factors such as seasons, type of prey, habitat, foraging techniques, and eagle age as a limitation affecting the foraging efficiency of birds. We found that floaters focused their diet exclusively on European Souslik, accounting for almost half (44.2%) of the eagle’s prey. Diet differences between floaters and breeders were due to higher Souslik and carrion consumption and lower Hedgehog predation by floater eagles. The diet diversity of breeding eagles (H = 3.297) was much higher than that of floaters (H = 1.748). Our model suggested that the foraging mode, habitat type, and season best explained the feeding success of non-territorial eagles (ΔAIC = 0.00, w = 0.42). Of all explanatory factors, “Kleptoparasitism” (β2 = −4.35), “Rodents” (β2 = −4.52), “Pasture” (β2 = 2.96), “Wheat” (β2 = 4.41), “In the air” (β2 = 4.16), and “Other habitats” (β2 = 4.17) had a pronounced effect. The factors “Spring–summer season” (β2 = −0.67) and “European Souslik” (β2 = −2.76) had a marginal effect in our models. Generally, the mean success rate of attack modes used by non-territorial eagles was 0.54 ± 0.50. Floaters successfully obtained food through: kleptoparasitism (43.10%), carrion feeding (24.14%), and high soar with vertical stoop (14.66%). Several important issues for the conservation of non-territorial Eastern Imperial Eagles arose from our research. The strong relation of floaters with the European Souslik calls for specific conservation measures aimed at the conservation of this type of prey and the restoration and appropriate management of its grassland habitats. The importance of the scavenging behavior of juvenile birds requires increased control of the use of poison baits and subsequent prosecution by state institutions. Protecting the most important temporary areas, improving institutional control against the use of poison baits, and intensifying awareness-raising campaigns among pigeon-fanciers and hunters are also of crucial importance for effective species conservation.
18
Restani, Marco, Alan R. Harmata, and Elizabeth M. Madden. "Numerical and Functional Responses of Migrant Bald Eagles Exploiting a Seasonally Concentrated Food Source." Condor 102, no. 3 (August 1, 2000): 561–68. http://dx.doi.org/10.1093/condor/102.3.561.
Full textAbstract:
AbstractWe determined the numerical and functional responses of migrant Bald Eagles (Haliaeetus leucocephalus) feeding on spawning kokanee salmon (Oncorhynchus nerka) at Hauser Reservoir, Montana from 1991–1995. Number of Bald Eagles was positively correlated with the fluctuating number of salmon carcasses during four of five years. Immigration and emigration rates were similar across years and were facilitated by several behavioral and physical characteristics of eagles: group foraging, communal roosting, and keen eyesight. Number of subadult eagles showed closer synchrony with density of salmon carcasses than did adult eagles. Eagles scavenging for salmon exhibited a Type II functional response. Handling times of scavenging eagles remained constant across the range of salmon carcass densities, whereas daily attack rates increased. Functional responses of scavenging eagles differed between age groups; adults exhibited a Type I response, whereas that of subadults could not be characterized. Handling times of scavenging adults were constant, but those of subadults increased with salmon density. Attack rates of scavenging adults increased with salmon carcass density. Consumption rates differed between age groups and among eagles using foraging modes of scavenging, stooping, and pirating, which suggests that eagles viewed live and dead salmon as alternative prey types. Bald Eagle scavenging of kokanee salmon was inversely density dependent.
19
Knight, Susan K., and Richard L. Knight. "Vigilance Patterns of Bald Eagles Feeding in Groups." Auk 103, no. 2 (April 1, 1986): 263–72. http://dx.doi.org/10.1093/auk/103.2.263.
Full textAbstract:
Abstract Patterns of vigilant behavior of wintering Bald Eagles (Haliaeetus leucocephalus) feeding on spawned salmon were examined in 1983-1984 on the Nooksack River in northwestern Washington. Vigilance in feeding birds has, in general, been attributed to predator detection; however, we proposed an additional function of vigilance in socially feeding birds that are vulnerable to food robbery and possible injury by conspecifics. We tested predictions of two nonexclusive hypotheses: (1) eagles look up while feeding to detect danger from humans, and (2) eagles look up while feeding to detect pirating attempts or avoid injury by conspecifics. Results suggest that the function of vigilance varies, depending on the size of the feeding group. Vigilance patterns of eagles feeding in small groups (1-4 eagles) and medium groups (5-7 eagles0 are consistent with hypothesis 1, whereas those of eagles feeding in large groups (8-14 eagles) are consistent with hypothesis 2. Eagles in small groups were more vigilant (measured as scanning time and rate of head raising) when feeding near potential danger (riverbank cover) than when far from danger. Adult eagles feeding in areas of intense human activity were more vigilant than immatures feeding at the same site and were more vigilant than both adults and immatures feeding at secluded sites. Vigilance declined as group size increased from 1 to 4 eagles, and increased as group size ranged from 8 to 14 eagles. Feeding eagles that were looking up at the time of a pirating attempt were more successful in keeping their food than eagles with their heads down. In feeding areas where human activity was minimal, eagles formed larger groups than at more disturbed sites.
20
Nikolenko, Elvira G. "III International Scientific and Practical Conference “Eagles of the Palearctic: Study and Conservation” and the International Workshop “Population Status and Problems of Conservation of the Saker Falcon”." Raptors Conservation, no. 47 (2023): 21–41. http://dx.doi.org/10.19074/1814-8654-2023-47-21-41.
Full textAbstract:
The Conference “Eagles of the Palearctic: Study and Conservation” is devoted to fundamental and practical issues in the study and protection of both individual species and populations of large birds of prey. The uniqueness of this Conference lies in the association of ornithologists from almost all over the world who contribute to the study and protection of eagles in the Palearctic. This review examines the reports presented at the Conference in 2023, outcomes analyzed various areas of study and protection of eagles, mainly the Eastern Imperial Eagle (Aquila heliaca) and the Steppe Eagle (Aquila nipalensis). The review also examines the reports from the satellite event – the International Workshop “Population Status and Problems of Conservation of the Saker Falcon”.
21
Sarasola, José Hernán, and Juan José Maceda. "Past and current evidence of persecution of the Endangered crowned eagle Harpyhaliaetus coronatus in Argentina." Oryx 40, no. 3 (July 2006): 347–50. http://dx.doi.org/10.1017/s0030605306001013.
Full textAbstract:
The crowned eagle Harpyhaliaetus coronatus is a large Neotropical eagle categorized as Endangered throughout its range. However, the threats to this species are poorly understood. We present data on the causes of death of crowned eagles in semi-arid forests of La Pampa province, central Argentina. Data was obtained from field surveys and from interviews with 62 local landowners during 1999–2004. Over this period five eagles were shot, one killed by a car, one was found dead in a cattle water trough, and one was found in captivity. From the interviews information was obtained about a further 10 cases of eagles being shot, disturbed or trapped. Five (13%) of 38 interviewed landowners who positively identified the species admitted having killed or disturbed eagles in the past but only two (5%) mentioned predation of eagles upon livestock as a problem. Persecution seems to be a significant threat to this species in central Argentina and future research and conservation action should be focused not only on gaining a better knowledge of the biology of the species but also on conservation and educational programmes involving local people.
22
Mlíkovský, Jiří. "The Food of the White-tailed Sea Eagle (Haliaeetus albicilla) at Lake Baikal, East Siberia." Slovak Raptor Journal 3, no. 1 (January 1, 2009): 35–39. http://dx.doi.org/10.2478/v10262-012-0031-5.
Full textAbstract:
The Food of the White-tailed Sea Eagle (Haliaeetus albicilla) at Lake Baikal, East Siberia A long-term study (1991-2001) of the food of White-tailed Sea Eagles in the Svâtoj Nos wetlands at Lake Baikal, Northeastern Russia, revealed that these eagles feed predominantly on water birds, mainly ducks. Anecdotal data from the Selenga Delta in Southeastern Lake Baikal indicate that White-tailed Sea Eagles generally prefer birds as their prey in the Lake Baikal area.
23
Ridpath, MG, and MG Brooker. "Age, Movements and the Management of the Wedge-Tailed Eagle, Aquila-Audax, in Arid Western Australia." Wildlife Research 13, no. 2 (1986): 245. http://dx.doi.org/10.1071/wr9860245.
Full textAbstract:
Four populations of wedge-tailed eagles were studied from 1967 to 1976 in the arid zone of Western Australia, and compared with data from the rnediterranean zone. The overall colour of eagles and the width of the pale bar on the dorsal surface of the wing were used to estimate ages in the field. Breeding usually started at 6-7 years old. The proportion of eagles of breeding age in the population varied between a quarter and two-thirds. A total of 355 eagles were banded (50% as nestlings) and 29 were recovered, 12 at >100 km, the furthest at 784 km away. Eagles of breeding age were probably sedentary even in drought, but as many as half those less than breeding age left the natal area. Most recoveries were within 2 years, but some bands were lost thereafter. Killing by man accounted for 54% of the recoveries in the arid zone. Such killing cropped the eagle population, the productivity of which varied according to its food supply. Killing was probably ineffective in reducing the numbers of eagles as it chiefly accounted for immatures, the birds most vulnerable to natural mortality. However, in habitats marginal for eagles and not used for sheep, such killing rates could have posed a threat to the species. Increases in land clearance and intensity of land usage could affect the wedge-tailed eagle in the future, even in the arid zone. Such effects would not be immediately obvious in such a long-lived, reproductively conservative species.
24
NIJMAN, VINCENT. "The endemic Bawean Serpent-eagle Spilornis baweanus: habitat use, abundance and conservation." Bird Conservation International 16, no. 2 (June 2006): 131–43. http://dx.doi.org/10.1017/s0959270906000219.
Full textAbstract:
The Bawean Serpent-eagle Spilornis baweanus is endemic to the 190 km2 island of Bawean in the Java Sea (Indonesia) where it is the only resident diurnal raptor. A 15 day study in 2002 revealed that the species is present in small numbers throughout the island. The eagle's abundance was assessed by an island-wide survey and by sampling 28 1 km2 plots covering five habitat types. There was a strong positive correlation between abundance and contact time in plots. Compared with other habitat types, the number of, and contact time with, serpent-eagles was higher in tall forest. The species was not recorded in mangrove and coastal forest. There was no correlation between the eagle's abundance and the nearest distance to villages. Based on the distribution of forest and the abundance of adult pairs within these forests, the available habitat totals 92 km2, in which some 60–75 adult serpent-eagles remain. Semi-structured interviews with the islanders revealed that recreational hunting poses the largest threat to the survival of the Bawean Serpent-eagle, and that the increase in recreational hunting was a relatively recent phenomenon. The forest on Bawean, including that in two reserves, is poorly protected and illegal logging and burning are widespread. The low degree of habitat protection, the severe threat posed by hunting and the very small population size of the eagle qualify the species to be included in the IUCN Red List as Critically Endangered. In order to safeguard the Bawean Serpent-eagle hunting must be stopped immediately and the remaining habitat needs to be better protected. This is probably best achieved by a conservation body in which local and regional authorities and NGOs cooperate.
25
Restrepo-Cardona, Juan Sebastián, Fabricio Narváez, Sebastián Kohn, Félix Hernán Vargas, and Santiago Zuluaga. "Human Persecution is An Important Threat to the Conservation of the Endangered Black-and-Chestnut Eagle in Northern Andes." Tropical Conservation Science 16 (January 2023): 194008292311523. http://dx.doi.org/10.1177/19400829231152353.
Full textAbstract:
Background and Research Aims The Black-and-chestnut Eagle ( Spizaetus isidori) has a total population of fewer than 1000 adult individuals, and is categorized as Endangered at the global level. The northern Andes (Ecuador and Colombia) represent one of the last population strongholds of the species. In this study, we analyzed human persecution of the Black-and-chestnut Eagle as retaliation or as a preventive measure against poultry predation, as well as other threats that have affected the species in this geographical region between 2000 and 2022. Methods In order to understand the human persecution and other threats faced by the Black-and-chestnut Eagle in the northern Andes, we compiled records of immature and adult individuals of the species that had been shot, captured, or had presented evidence of any other affectations during the last 23 years. Results We found a total of 96 Black-and-chestnut Eagles affected by different threats. Human persecution of the species to prevent poultry predation was the motive in 81% (46 of 57) of the cases of shot eagles, 67% (10 of 15) of those captured illegally, 30% (3 of 10) of those in which the cause of affectation was undetermined and for one individual that had been stabbed. Immature eagles were more affected than adult eagles by human persecution. Black-and-chestnut Eagles were also affected by electrocution, illegal trafficking and collision with vehicle. Conclusion Human persecution as retaliation or as a preventive measure against poultry predation is an important threat to the conservation of the Black-and-chestnut Eagle in northern Andes. Implications for Conservation Strict application of laws at human persecution sites, identification and monitoring of areas with high risk of human-eagle conflict, development of environmental educational programs, strengthening of the technical capacities of rural communities, maintaining or even increasing forest cover, and reducing the exposure of poultry by using enclosures are key for Black-and-chestnut Eagle conservation in the northern Andes.
26
Duerr, Adam E., Amy E. Parsons, Laura R. Nagy, Michael J. Kuehn, and Peter H. Bloom. "Effectiveness of an artificial intelligence-based system to curtail wind turbines to reduce eagle collisions." PLOS ONE 18, no. 1 (January 26, 2023): e0278754. http://dx.doi.org/10.1371/journal.pone.0278754.
Full textAbstract:
Operating wind-power projects often includes protecting volant wildlife. One method for doing this uses an automated system to detect, identify (through use of artificial intelligence; AI), track animals (targets) and curtail turbines when risk of a collision is high. However, assessments of the effectiveness, in terms of identification accuracy and subsequent turbine curtailment of such systems are lacking. Over 1 year, we assessed such an automated system installed at a wind project in California, USA to determine its identification accuracy and rates at which "virtual” curtailments were ordered (without slowing turbines), for eagles (intended targets) and non-eagle targets. The system correctly identified 77% of eagles and 85% of non-eagles. Curtailment orders occurred 6 times more frequently for non-eagle targets (5,439) than for eagle targets (850). Greater abundance of common ravens that were misidentified as eagles influenced the effectiveness of the system by greatly increasing unintended curtailment orders. The balance between costs (price of the IdentiFlight system, reduced energy generation, turbine wear and maintenance) and benefits (reduced collisions between intended target species and turbines) may depend upon the biological setting, speed at which operators can curtail turbines, and the objectives of the operator when considering the IdentiFlight system.
27
Walters, K. E., J. D. Reynolds, and R. C. Ydenberg. "Ideal free eagles: Bald Eagle (Haliaeetus leucocephalus) distribution in relation to Pacific salmon (Oncorhynchus spp.) availability on four spawning rivers." Canadian Journal of Zoology 99, no. 9 (September 2021): 792–800. http://dx.doi.org/10.1139/cjz-2020-0191.
Full textAbstract:
The movement of individuals according to the availability of resources has a fundamental effect on animal distributions. In the Pacific Northwest, Bald Eagles (Haliaeetus leucocephalus (Linnaeus, 1766)) rely heavily on scavenging opportunities during the non-breeding period, and their distribution and movements are thought to be strongly influenced by the availability of post-spawning Pacific salmon (genus Oncorhynchus Suckley, 1861) carcasses. We surveyed the abundance of eagles and salmon on four adjacent rivers on Vancouver Island, British Columbia, Canada, during the 2017 fall spawning season. Salmon began to arrive in late September, peaked in abundance in mid-November, and were absent after early December. The seasonal progression of Bald Eagle abundance matched that of salmon carcass availability. The slope of proportional eagle–salmon relationship was significantly positive, though lower than the 1:1 match predicted by Ideal Free Distribution theory. The numerical response of Bald Eagles to salmon abundance was elevated on one of the rivers, potentially due to physical features such as sandbars and mudflats that increased the availability of carcasses and provided access points for eagles.
28
Dykstra, Cheryl R., William H. Karasov, Michael W. Meyer, and D. Keith Warnke. "Daily Energy Expenditure of Nestling Bald Eagles in Northern Wisconsin." Condor 103, no. 1 (February 1, 2001): 175–79. http://dx.doi.org/10.1093/condor/103.1.175.
Full textAbstract:
Abstract We measured field metabolic rate of nestling Bald Eagles (Haliaeetus leucocephalus) in northern Wisconsin, using doubly-labeled water. In inland northern Wisconsin and along the Wisconsin Lake Superior shore, eaglets aged 39–60 days, weighing 3.08–4.85 kg, expended an average of 2,427 ± 100 kJ day−1. Nestling field metabolic rate was weakly correlated with nestling age, but not with mass. Field metabolic rate of eaglets can be used to estimate the biomass of food that adult eagles must provide from their environment, a datum that is important for determination of habitat suitability.
29
Đekić, Đorđe, and Dragana Milić. "Motif of single-headed and double-headed eagle in Raška in the XIII century." Bastina, no. 56 (2022): 319–34. http://dx.doi.org/10.5937/bastina32-36210.
Full textAbstract:
The motif of a single-headed and double-headed eagle first appeared in Serbian medieval art under the influence of the Byzantine Empire or Christian tradition. This motif was used by the Byzantine Empire as a symbol of royal dignity and as a representation of saints. Since the eagle is regarded as a symbol of Jesus Christ, the resurrection, the Holy Evangelist John, and etc., Christian influence is more visible in literature. The use of the eagle as a motif in Raška was heightened during Grand župan Stefan Nemanja's reign and continued through his successors. Studenica monastery depicts both single-headed and double-headed eagle motifs. A single-headed eagle is a fresco painted in a double circle, and a doubleheaded eagle is a fresco painted as kolasta azdija, which represents a motif of golden double-headed eagles in double circles. Kolasta azdija can be found on the gowns of King Stefan the First-Crowned and his son King Radoslav in the Žiča monastery. A motif of a red double-headed eagle was also used as a decorative element of the St. George's wall and cloak. At Mileševa monastery, golden encircled double-headed eagles adorned the gowns of King Stefan the First-Crowned and his sons Radoslav and Vladislav. The motif of single-headed eagles in circles can be found as a unique example on Knez Stefan's gown in the Morača monastery. An eagle can be found as a motif in manuscripts, on the seal, and as part of the church's interior decoration. During King Uroš I and his successors' reigns, double-headed eagles vanished as a symbol of royal dignity, but they remained as a Christian symbol until the end of the XIII century.
30
Probst, Remo, Matthias Schmidt, Michael McGrady, and Christian Pichler. "GPS Tracking Reveals the White-Tailed Eagle Haliaeetus albicilla as an Ambassador for the Natura 2000 Network." Diversity 16, no. 3 (February 25, 2024): 145. http://dx.doi.org/10.3390/d16030145.
Full textAbstract:
The Natura 2000 network of protected areas is the backbone of species conservation in the European Union. We investigated whether Austrian-hatched white-tailed eagles (Haliaeetus albicilla) make particular use of this multinational network during their natal dispersal, and what habitats were of importance to the eagles. We analyzed the utilization distribution of 907,466 GPS locations from 38 dispersing white-tailed eagles using a dynamic Brownian Bridge Movement Model. Eagles ranged over a huge area of central-eastern Europe. Natura 2000 sites overlapped with 67% of the resulting 50% isopleth; i.e., a high probability of utilization of Natura 2000 areas by white-tailed eagles was found. White-tailed eagles used wetlands, waterbodies, and deciduous forests adjacent to wet habitats disproportionately often. Coniferous forests and settlements were avoided. Anthropogenically caused mortalities hardly occurred within Natura 2000 sites. Our study suggests that the Natura 2000 network is a crucial tool for conserving the white-tailed eagle. This top predator is an ambassador for the Natura 2000 idea during all life stages, and should continue to be a conservation priority of the network.
31
Debus, Stephen, and G. N. Wilkins. "Growth of a nestling Little Eagle Hieraaetus morphnoides, with comments on rescue of pre-fledglings." Australian Field Ornithology 41 (2024): 86–91. http://dx.doi.org/10.20938/afo41086091.
Full textAbstract:
A nestling Little Eagle Hieraaetus morphnoides was photographed and videoed from age 3 weeks until prematurely fledged at 8 weeks near Emmaville, New South Wales, during November–December 2023. This visual record, with notes, of physical and behavioural development supplements descriptions and the few earlier photographs of age-related growth stages of nestlings of this species. The adult Eagles tolerated observation on the ground from ~70 m away, without adverse effects on the breeding event. Brief descriptions of parental behaviour at these weekly stages, and at the incubation and hatching stages, are included. A predator killed the pre-fledged but feathered eaglet after an overnight storm blew the eaglet to the ground before it could fly. Rescue of such grounded fledglings is discussed.
32
CARO, JESÚS, DIEGO ONTIVEROS, MANUEL PIZARRO, and JUAN M. PLEGUEZUELOS. "Habitat features of settlement areas used by floaters of Bonelli’s and Golden Eagles." Bird Conservation International 21, no. 1 (April 23, 2010): 59–71. http://dx.doi.org/10.1017/s0959270910000213.
Full textAbstract:
SummaryBonelli’s Eagle Hieraaetus fasciatus and Golden Eagle Aquila chrysaetos are two declining species, in which floaters tend to be located outside of breeding territories during the dispersal period, in so-called settlement areas. We studied settlement areas for both these long-lived raptors in the southern Iberian Peninsula, to gain a better understanding of the ecological requirements of the eagles during their long pre-adult stage, a period accounting for around 80% of the species’ mortality. Eagle abundance was calculated by road censuses, and habitat characteristics of settlement and non-settlement areas compared by General Discriminant Analysis (GDA) and Logistic Regression (LR). The best model of GDA and LR incorporated the abundance of main prey for eagles (rabbits, partridges) and orchard surface area, and explained 100% of eagle presence; the best model selected by GDA also included habitat heterogeneity. Both eagles tended to share settlement areas in the southern Iberian Peninsula and, when they did not, the mean annual temperature and slope appeared to explain the segregation between the two species. Management measures for the conservation of both threatened species during the dispersal period should be focused on identifying settlement areas, maintaining high prey densities and maximum habitat heterogeneity.
33
Weiss, N. "Steppe Eagle’s population structure migrating through the bottleneck of Eilat in spring." Raptors Conservation, no. 2 (2023): 269–70. http://dx.doi.org/10.19074/1814-8654-2023-2-269-270.
Full textAbstract:
Steppe Eagles (Aquila nipalensis) migrate in large numbers past key migration flyways from almost its entire breeding region. On its spring migration route from Africa many birds fly through the bottleneck of Eilat in southern Israel. Migration timing and age structures in the population are often key elements of conservation works. In the four springs of 2015 to 2018 we systematically counted the passing Steppe Eagles at two count stations. An average of 15,039 Steppe Eagles were counted per spring. We also recorded the ages of many of the Eagles. We found patterns in the Eagle's migration that is related to the age of the eagles. Adults arrive early and are most abundant, followed by sub adults, and juveniles in timing and numbers. Furthermore, we compared our data of the structure of the passing populations with different flyways and wintering sites and found significant differences. The flyway in Eilat is mostly occupied by adult migrating birds, 72% of the aged birds were adults in the survey. The different usage of flyways by ages can be an important factor in future conservation projects.
34
Janson, Charles H., Javier Monzón, and M. Celia Baldovino. "Experimental analysis of predator and prey detection abilities in rainforest: who has the advantage?" Behaviour 151, no. 10 (2014): 1491–512. http://dx.doi.org/10.1163/1568539x-00003198.
Full textAbstract:
Recent theoretical analyses have shown that anti-predator benefits in social groups depend on the attack distance of the predator relative to prey spacing within groups. Both attack distance and prey spacing depend on the ability of predator and prey to detect each other. Previous work on forest predators suggest that many depend on surprise to ambush their prey, thus we test the hypothesis that detection distances by eagles of monkeys are greater than vice versa, despite the supposed advantages of sociality in facilitating detection of predators by prey. We used field experiments in the wild to assess detection distances of both raptor predators and their natural monkey prey. Live hawk-eagles (Spizaetus), under rehabilitation from injury, were placed tethered to perches in the home ranges of two habituated wild study groups of tufted capuchin monkeys (Cebus (apella) nigritus) in Iguazú National Park, Argentina. Analysis of video footage of the eagles during the approach of capuchin monkey groups allowed us to define the first moment of behaviours indicating detection by the eagle; detection behaviours of the monkeys near the eagle were recorded observationally by field assistants. The hawk-eagles always detected the monkeys (average distance 31.9 m) before the monkeys detected the predators (average distance 9.4 m). Predators always initially detected one or two spatially-peripheral individuals of the prey group. Distance of detection by the predators (and thus maximum possible attack distances) was significantly less than the prey group spread of 42–57 m. The short detection (and consequent short attack) distances by eagles of monkey prey in this habitat suggests that early warning of attacking eagles may not be a primary benefit of grouping in this case.
35
Mirski, Paweł, and Ervin Komar. "The White-Tailed Eagle, the Apex Predator, Adjusts Diet towards Larger Prey in Suboptimal Territories." Diversity 15, no. 6 (June 6, 2023): 747. http://dx.doi.org/10.3390/d15060747.
Full textAbstract:
The White-tailed eagle, an apex predator, is currently recovering its populations across Europe and has already reached high numbers in many countries. This led to the saturation of eagles in optimal habitats and their encroachment on suboptimal ones. We aimed to compare the diet of White-tailed eagles in optimal and suboptimal conditions in northeastern Poland to investigate how population development affected prey composition, which is expected to be lacking in suboptimal eagle territories. We have monitored eagle nests with trail cameras to investigate their diet objectively and precisely. In order to compare territories of different quality, we have conducted modeling of habitat suitability using data on nest locations prior to their saturation. Using recorded photos of the prey, we measured their size and estimated their weight to check if the size and biomass of the prey are comparable between optimal and suboptimal territories. We found that eagles in the latter conditions were not limited by prey biomass but turned to alternative prey and brought larger prey. The alternative prey were large birds such as White storks and Common cranes, but also chicks of other avian predators that were robbed from their nests. Most probably, eagles cope with a lack of optimal prey by ranging farther and exploring non-optimal foraging habitats. We conclude that the diet flexibility of White-tailed eagle enables him to still increase its numbers despite already high densities. Our study also shows that this species might possibly impact the White stork population, as seen in the case of the Black stork and some seabird species.
36
Trail, Pepper W. "Identifying Bald Versus Golden Eagle Bones: A Primer for Wildlife Biologists and Law Enforcement Officers." Journal of Fish and Wildlife Management 8, no. 2 (July 1, 2017): 596–610. http://dx.doi.org/10.3996/042017-jfwm-035.
Full textAbstract:
Abstract Remains of bald eagles Haliaeetus leucocephalus and golden eagles Aquila chrysaetos are regularly encountered in avian mortality surveys and wildlife crime investigations. These species exhibit well-documented plumage differences, allowing identification in most instances when feathers are present. However, skeletal remains are much more difficult to identify and may be the only material available after mortality events (e.g., decomposed remains associated with power lines or wind turbines). Eagle bones are also sometimes incorporated into crafted items without other associated remains. I describe and illustrate shape-based osteological characters that have been determined to be reliable for distinguishing most major bones of bald versus golden eagles. Using the annotated photographs provided as a guide, nonspecialists will be able to identify eagle skeletal remains with high accuracy. This information will be of interest to wildlife law enforcement officers; state, federal, and tribal wildlife biologists documenting avian mortality; and anthropologists and archaeologists.
37
Bortolotti, Gary R. "Frequency of Protocalliphora avium (Diptera: Calliphoridae) infestations on bald eagles (Haliaeetus leucocephalus)." Canadian Journal of Zoology 63, no. 1 (January 1, 1985): 165–68. http://dx.doi.org/10.1139/z85-025.
Full textAbstract:
This is the first record of nestling bald eagles as hosts of the parasitic blowfly Protocalliphora avium (Diptera: Calliphoridae). The frequency of infestation of the hematophagous larvae was determined by repeatedly examining eaglets over the entire 10- to 12-week nestling period from 1980 to 1982 in north-central Saskatchewan. Seventy-two nestlings were examined a total of 461 times. All nestlings less than 49 days old were parasitized by large numbers of larvae in the aural cavities, on the nape of the neck, and on the top of the head. The frequency of parasitism was high from the time the eaglets hatched until they were 16 days old when it sharply declined. The birds were repeatedly infested, suggesting that P. avium may have been an intermittent feeder. There was no difference between the frequency of infestation in nests containing one or two chicks, nor between the first-hatched and second-hatched eaglet within a brood. Factors associated with the physical and behavioural development of the eaglets, rather than a seasonal effect on the parasites, may account for the decline and cessation of infestation.
38
Dravecký, Miroslav, Boris Maderič, Karol Šotnár, Štefan Danko, Stanislav Harvančík, Ján Kicko, Dušan Karaska, et al. "Lesser Spotted Eagle (Aquila pomarina) colour ringing programme and its first results in the period 2000-2008 in Slovakia." Slovak Raptor Journal 2, no. 1 (January 1, 2008): 27–36. http://dx.doi.org/10.2478/v10262-012-0016-4.
Full textAbstract:
Lesser Spotted Eagle (Aquila pomarina) colour ringing programme and its first results in the period 2000-2008 in Slovakia In Slovakia during 2000-2008, 636 Lesser Spotted Eagles (Aquila pomarina) were marked with readable colour rings with double figure code. This is the highest number of Lesser Spotted Eagles marked in such a way in Europe. From this sample, 621 ind. (97.6 %) were chicks at the nest and 15 ind. (2.4 %) were adult birds which were trapped and consequently ringed. In this period, 2 colour series of rings have been used in Slovakia. In 2000 the ringing started with yellow rings, and up until the end of 2008, 631 ex. (616 young and 15 adults) were ringed. In 2008, the ringing started with light blue series of rings and 5 young at the nest were ringed. In addition to readable rings, aluminium ornithological rings of the Ringing Centres of Czech Republic (NM Praha) and Slovakia (NM Bratislava) have been used. The yellow series was used in fewer numbers also in Germany and Poland for marking the Lesser Spotted Eagle (Aquila pomarina), the Greater Spotted Eagle (Aquila clanga), and eventually their hybrids. In this article the authors reported first observations in Slovakia of such marked Lesser Spotted Eagles in the field. Observed eagles were 1, 2, 4, 5, 7 and 8 years old. Some of them were already breeding and were observed taking care of their chicks.
39
Dulmaa, K. "Study of Breeding and Migrations of the Golden Eagle in Mongolia." Raptors Conservation, no. 2 (2023): 30–31. http://dx.doi.org/10.19074/1814-8654-2023-2-30-31.
Full textAbstract:
Golden Eagles (Aquila chrysaetos) play a crucial role in the ecosystems of the Bayan-Ulgii province and its neighboring regions. Our research focuses on the comprehensive survey of Golden Eagle nests and study of their migration patterns via the satellite tracking, providing valuable insights into population dynamics and migratory behaviors. In the years 2021 and 2022, we accomplished an extensive search for Golden Eagle eyries across 13 diverse counties in Bayan-Ulgii province, including Altai, Altantsugts, Bayannuur, Bayan-Ulgii, Bugat, Deluun, Erdeneburen, Nogoonnuur, Sagsai, Tolbo, Tsagaannuur, Tsengel, and Ulaankhus. This collaborative effort in partnership with local communities and herders allowed us to identify and document a total of 75 Golden Eagle nests, with 49 being active during this two-year period. To deepen our understanding of these majestic birds, a satellite tracking program was started in September 2019 during the Ulaankhus Eagle Festival. Through GPS tagging, we monitored the migration of five Golden Eagles, previously used in Kazakh falconry and subsequently released. This tracking initiative provided us with valuable data on their movements and behaviors, shedding light on their survival challenges and migration routes. Our research not only contributes to the conservation efforts of Golden Eagles but also enhances our understanding of the interconnectedness of various raptor species within the region, including Bearded Vultures (Gypaetus barbatus), Cinereous Vultures (Aegypius monachus), Black Kites (Milvus migrans), Steppe Eagles (Aquila nipalensis), Peregrine Falcons (Falco peregrinus), and Saker Falcons (Falco cherrug). The study of these species in their natural habitats enriches our understanding of the intricate ecological dynamics at play. By sharing our findings, we aim to foster a deeper appreciation for these iconic birds and promote their conservation in the Bayan-Ulgii province and beyond. Our presentation will highlight the results of our Golden Eagle nest survey and tracking, emphasizing the importance of community involvement in wildlife research and conservation.
40
Dekker, Dick, and Mark C. Drever. "Kleptoparasitism by Bald Eagles (Haliaeetus leucocephalus) as a factor in reducing Peregrine Falcon (Falco peregrinus) predation on Dunlin (Calidris alpina) wintering in British Columbia." Canadian Field-Naturalist 129, no. 2 (August 4, 2015): 159. http://dx.doi.org/10.22621/cfn.v129i2.1696.
Full textAbstract:
Kleptoparasitism, or food piracy, is common in a wide range of taxa, particularly among predators, with the larger species forcing smaller species to surrender their catch. The Bald Eagle (Haliaeetus leucocephalus) is known to rob Peregrine Falcons (Falco peregrinus) of just-caught prey. We present time series of kleptoparasitic interactions between eagles and peregrines hunting Dunlin (Calidris alpina) that were wintering at Boundary Bay in the Fraser River valley, British Columbia. In 1108 hours of observation during January, intermittently between 1994 and 2014, we recorded 667 sightings of Peregrine Falcons, including 817 attacks on Dunlin resulting in 120 captures. The population of wintering Bald Eagles in the study area increased from about 200 in 1994 to 1800 in 2014, while the rate of kleptoparasitism at the expense of peregrines increased from 0.05 to 0.20. The increase in the number of Bald Eagles coincided with a decline in January sightings of Peregrine Falcons, which suggests that some falcons may have left the study area because of interference from eagles. The decrease in Peregrine Falcon numbers can be expected to have led to reduced predation risk for Dunlins. Christmas Bird Counts conducted in the Fraser River Valley have underscored the fluctuation in eagle and peregrine numbers reported here.
41
Karyakin, I. V., E. G. Nikolenko, and E. P. Shnayder. "Steppe Eagle in the Altai-Sayan Region – research results 2019–2023." Raptors Conservation, no. 2 (2023): 233–41. http://dx.doi.org/10.19074/1814-8654-2023-2-233-241.
Full textAbstract:
According to the Red List of IUCN, Steppe Eagle (Aquila nipalensis) is a globally Endangered (EN) species, included in the Red Data Book of Russia and protected throughout the country. Steppe Eagle breeding range in Russia covers semi-desert and steppe areas from Kalmykia in the west to Dauria in the east. The Altai-Sayan Ecoregion (ASER) is key for Steppe Eagle: about half of the entire breeding population of the species in Russia is concentrated here. Therefore, monitoring Altai-Sayan Steppe Eagle breeding groups is very important. In ASER Steppe Egle nests in steppe basins, except for Kuznetsk, including narrow steppe valleys of the Chuya and Katun rivers in Central Altai, as well as in the highlands of Southeastern Altai, partly Tanu-Ola and Western Sayan, including the high-mountain Ukok plateau. The total number of the species nesting in the ASER, considering the foothills of Altai Territory, in 2018 was estimated at 1400–1800 pairs. Currently population does not show a fundamental change, despite various negative and positive dynamics in different ASER breeding groups. By 2022, 756 eagle breeding territories have been identified in the region, which is 47.25% of the estimated species population. About 50% of favorable Steppe Eagle habitats identified during GIS modeling are not covered by survey, although nesting of the species was established in all clusters of modeled habitats during irregular visits. Thus, we know the entire Steppe Eagle breeding range in ASER, including areas where isolated pairs breed in suboptimal conditions. Annual monitoring is carried out in 68 Steppe Eagle breeding territories, which is 9% of the known breeding territories; over a three-year period, 256 breeding territories (33.9%) were monitored, over five years – 312 (41.3%). We regularly monitor breeding groups in the most problematic areas in terms of anthropogenic influence, and in those less impacted by human economic activity: on the left bank of Tes River in the Ubsunur basin, on the Tanu-Ola ridge, in Tuva basin of the Republic of Tyva, in Minusinsk Basin in the Republic of Khakassia and the Krasnoyarsk Territory, on the periphery of the Chui steppe, on the Sailyugem ridge and Ust-Kan basin of the Altai Republic, and in the foothills of Altai within the Altai Territory. Ukok and Southwestern Tyva where main Steppe Eagle breeding groups are less susceptible to anthropogenic factors have not been visited in recent years. Diet analysis showed that Steppe Eagles are quite flexible in managing prey resources and using a wide food range, both typical steppe and intrazonal species, diurnal and nocturnal (the latter are represented mainly by roadkill: Jerboas, Hedgehogs, and other species). In particular, eagles nesting in steppe and highlands above forests have such species as Squirrels (Sciurus vulgaris), Woodpeckers (Picidae sp.), and Bullfinches (Pyrrhula pyrrhula), possibly picked up from roads as well. As eagles most often nest within sight of farms and roads, eagles regularly use them to obtain food, picking up animals that that have died due to various reasons. It increases the threat of poisoning, collision with vehicles, or shooting. Despite the plasticity of Steppe Eagle hunting behaviour, they are closely connected to the mass colonial burrowing rodents (mainly Ground Squirrels Spermophilus sp. and Pikas Ochotona sp.), and high abundance and/or availability of these species in the spring determine both nest occupation and breeding success. If the spring abundance or availability (due to late spring) of basic food items is insufficient, Steppe Eagles do not begin to breed, and in half of the cases leave their breeding territories by mid-summer. Recently we have begun to study Steppe Eagle migration and philopatry not only by ringing, but using transmitters too, in addition to classical monitoring of breeding groups and control of breeding territories occupancy, partner change using photo and video observation of nests, molecular methods, breeding success, productivity, diet. In order to study migrations, 30 Steppe Eagles were tagged with transmitters (Aquila – 22 ind., Druid – 5 ind., Ecotone – 2 ind., GPS-Collars – 1 ind.). Tracking showed that most juvenile birds migrate in the western Circum-Himalayan Corridor, bypassing the high mountains of Central Asia. Only two birds migrated south through Tibet, and both died (one bird crossed the Himalayas but died in Nepal during the winter). Most eagles do not return to natal region in the first year, but wander during their first summer in Kazakhstan, and therefore this country plays a key role in the viability of the Altai-Sayan Steppe Eagle breeding groups. Visits to natal areas are observed from the second to third summer, and during fourth summer eagles begin to select territories and form pairs. Of the five eagles tagged with transmitters (one female and four males) whose home territories were visited during the fourth summer, four males had partners and nest outlines in chosen breeding territories, but only one male bred successfully (female did not have a partner and roamed widely). All eagles returned to their natal region for the summer by sexual maturity and occupied areas no further than 50 km (3, 36, 43 and 50 km) from nests in which they were born. Reproduction of a pair lasts four years on average in control areas, meaning that every four years reproduction is paused for one to four years due to death of one of the partners. It is noteworthy that out of five fledglings tagged with transmitters and returned to the natal region by puberty, not one of them found their parents alive – all parents died during this period and were replaced by young eagles. Over a five-year period, the loss of breeding territories where pairs disbanded was compensated by the formation of new territories by younger birds in almost all control areas. The exception is Sailyugem ridge in the Altai Republic, where anti-plague service carried out the so-called village deratization outside populated areas (on outposts and farms), which led to loss of 30% of nesting pairs in the local Steppe Eagle breeding group due to poisoning with anticoagulants (half of them have not yet recovered). An increase in the Steppe Eagle abundance was noted in Khakassia – by 7.14% between 2011 and 2018, which was initially associated with redistribution of Steppe Eagle breeding pairs to abandoned Eastern Imperial Eagle (Aquila heliaca) territories, but recalculation of accounting indicators for all Khakass territories showed the remaining real increase in the species abundance. However, in 2019–2022, this increase was reversed (-3.16% of the 2018 estimate) due to displacement of Steppe Eagles from breeding territories by Golden Eagles (Aquila chrysaetos) and the dissolution of some pairs for unknown reasons. In the Republic of Tyva, Steppe Eagle abundance 2008–2018 after a decline due to poisoning with bromadialone in Mongolia in 2001–2002. By 2013, Steppe Eagle abundance in Tyva was estimated at 300–400 breeding pairs (Karyakin, 2013; Nikolenko, Karyakin, 2013), by 2019 – at 311–422 pairs. It was suggested that by 2020 Steppe Eagle would have fully recovered its abundance in Tyva to the 2000 estimate of 373–453 pairs (Karyakin et al., 2018; 2019). However, it did not happen, and the abundance have stabilized at 305–410 pairs. Even though Steppe Eagle began to occupy artificial forest plantations and nest in trees and threat of mortality on power lines in Tyva has been almost completely eliminated in recent years, restoration of the former Steppe Eagle breeding territories has slowed down for a number of reasons: an increase in the number of summer livestock stops in suitable habitats (because of government subsidies), the climate factor (fully feathered nestlings die in thunderstorms with hail, which became regular in July, and excessive moisture leads to intense vegetation, making prey and fledglings die of hunger), local residents killing eagles on purpose (shooting at nests) or accidentally (death under car wheels), and predation by herding dogs. At the same time, Steppe Eagle abundance has remained stable in the highlands of Tanu-Ola during these years. Despite a certain influence of local negative factors on the Altai-Sayan Steppe Eagle breeding groups, the main reason for the frequent dissolution of pairs lies outside the breeding range. We assume that the main contributor to such a short eagle life expectancy is poisoning in wintering grounds. It is already known that Steppe Eagles form aggregations in landfills and cattle burials, where they can accumulate various toxic substances, from non-steroidal anti-inflammatory drugs to anticoagulants and heavy metals. But so far chemical contamination of the species has not been studied at all. Another problem for at least some eagles flying to wintering grounds in India is the increasing mortality observed in eagles that were ringed and tagged with transmitters due to avian botulism, which is increasingly occurring on the salt lakes and sores of Northwest India. More than 23,500 birds died from avian botulism in 2019 on the lake Sambar and its vicinity (in Jaipur and Nagaur districts) in Rajasthan (Singh, Sen, 2023). Steppe Eagle fed on bird remains and died as well. This major disaster has received publicity, but eagle death on the smaller scale occurs regularly and is growing every year. Botulism outbreaks are likely to become more frequent as climate change alters wetland conditions in favor of the pathogen, as seen in large salt water bodies of Kutch in Gujarat and Sambar in Rajasthan. If the situation does not change, these areas may become “ecological traps” for Steppe Eagle. Considering the enormous mortality of adult birds, which occurs mainly outside of the ASER, it is necessary to understand its causes. Since we assume the leading role of poisoning in Steppe Eagle mortality, further studies of chemical contamination of birds and clarification of their immune status regarding botulism is urgently needed.
42
Dravecký, Miroslav, Urmas Sellis, Ugis Bergmanis, Valery Dombrovski, Jan Lontkowski, Grzegorz Maciorowski, Boris Maderič, et al. "Colour ringing of the Spotted Eagles (Aquila pomarina, Aquila clanga and their hybrids) in Europe - a review." Slovak Raptor Journal 2, no. 1 (January 1, 2008): 37–52. http://dx.doi.org/10.2478/v10262-012-0017-3.
Full textAbstract:
Colour ringing of the Spotted Eagles (Aquila pomarina, Aquila clanga and their hybrids) in Europe - a review During the years 2000-2008 1377 Spotted Eagles (SE) (Aquila pomarina, Aquila clanga and their hybrids) have been colour ringed in Europe. Out of these, 1303 (94.6 %) were young birds and 74 (5.4 %) were adults. Out of the total, 1290 (93.7 %) were the Aquila pomarina Lesser Spotted Eagles (LSE) - 1229 (95.3 %) young and 61 (4.7 %) adults, 50 (3.6 %) were the Aquila clanga Greater Spotted Eagles (GSE) - 44 (88.0 %) young and 6 (12.0 %) adults and 37 (2.7 %) were the Aquila pomarina x Aquila clanga hybrids (LSE x GSE) - 30 (81.1 %) young and 7 (18.9 %) adults. With respect to the individual European countries the following SE species and numbers were ringed: Slovakia 636 (46.2 %), Poland 333 (24.2 %), Estonia 153 (11.1 %), Germany 116 (8.4 %), Lithuania 68 (4.9 %), Latvia 45 (3.3 %) and Belarus 26 (1.9 %). In the article authors presents a review on Spotted Eagle colour ringing programmes running in individual European countries.
43
Jung, Thomas S. "Coyote (<i>Canis latrans</i>) predation of colonial rodents facilitated by Golden Eagles (<i>Aquila chrysaetos</i>)." Canadian Field-Naturalist 135, no. 2 (October 3, 2021): 120–23. http://dx.doi.org/10.22621/cfn.v135i2.2561.
Full textAbstract:
Interactions between Coyote (Canis latrans) and Golden Eagle (Aquila chrysaetos) are complex and likely not yet fully documented or understood. I observed a Coyote prey on a Black-tailed Prairie Dog (Cynomys ludovicianus) at the edge of a large colony in Grasslands National Park, Saskatchewan. The prairie dogs were vigilant toward three Golden Eagles circling above, and the Coyote apparently used this to its advantage. As such, the eagles appeared to facilitate the ability of the Coyote to rush in virtually undetected and prey on a prairie dog that was distracted by the avian predators. This observation is of scientific interest because it is another example of the varied interactions between Coyotes and Golden Eagles, which is competitive and includes kleptoparasitism.
44
Demerdzhiev, Dimitar Atanasov, Dobromir Damyanov Dobrev, and Zlatozar Nikolaev Boev. "Grassland Alterations Do Not Affect Breeding Success, but Can Explain Dietary Shifts of a Generalist Raptor Species." Diversity 15, no. 3 (March 13, 2023): 422. http://dx.doi.org/10.3390/d15030422.
Full textAbstract:
Habitat alteration is a widespread threat severely affecting large raptors because of their low density and the huge area they inhabit. In this study, we assessed whether human-driven habitat alterations mediated dietary shifts of apex predators, focusing on the Eastern imperial eagle (Aquila heliaca). Following a bottom-up conception (before–after), we evaluated the effect of grassland change on the eagle’s dietary shift and breeding success. Land use patterns underwent a significant transformation over the study period, creating a large decrease in grasslands. The territories lost an average of 25.79% of their grasslands. Habitat alteration mediated dietary shifts, but had no reproductive consequences for eagles. Eagles became 1.90 times more likely to predate on northern white-breasted hedgehog and 1.62 times more likely to forage on white stork in the period after grassland alteration. The frequency of tortoises also increased, and they were 4.04 times more likely to be predated on in the years after transformation. Conversely, brown hare was 0.51 times less likely to be consumed in the grassland loss period, while this likelihood was 0.54 times lower for rodents and 0.64 times lower for the European souslik. Doves, meanwhile, were 2.73 times more likely to be predated on in the years following grassland destruction. We found that the presence and biomass of songbirds correlated negatively with the breeding success of eagles, and biomass supply from European souslik was negatively associated with breeding success, while the white stork’s presence and biomass resulted positively in more progeny. Diet diversity did not have an effect on the eagle’s reproduction. The responses of these eagles may vary across territories, depending on how they rank their prey, as the territory effect was a powerful factor shaping dietary shifts for this top predator. Our results offer new evidence of the link between habitat alteration, dietary shifts, and reproductive success, contributing to our understanding of the enigmatic mechanism through which an apex predator successfully adapts to large-scale land use pattern transformation by increasing dietary specialization. We recommend restoration of habitat complexity, including preservation of field margins, grassland patches with scattered small shrub formations, and grassland margins between medium-sized arable lands, promotion of measures for traditional grassland management through gradual grazing, and a ban on the use of shredders.
45
Kaptyonkina, A. G., G. I. Pulikova, N. A. Sagaliev, and I. V. Karyakin. "The Imperial Eagle in the south-east of Kazakhstan 2022–2023: distribution, population numbers, threats." Raptors Conservation, no. 2 (2023): 329–34. http://dx.doi.org/10.19074/1814-8654-2023-2-329-334.
Full textAbstract:
The Imperial Eagle (Aquila heliaca) is one of the rare species of eagles breeding in Kazakhstan and inhabiting almost the entire territory of the country. The south and south-east of Kazakhstan is the southeastern border of the breeding range of the species (Karyakin, 2020). It is this part of the range that will be considered in this paper. The Imperial Eagle is classified as a Vulnerable species by the IUCN (BirdLife International, 2019), and in Kazakhstan it is listed in the Red Data Book as a Rare and Declining Species (Category III) (Pfeffer, 2010). The global population of imperial eagles as of 2016 was estimated at 2.5–9,900 adults (BirdLife International, 2019), but the current estimate of the global population is 8099–9981 breeding pairs, whereof Kazakhstan has 3420–4260 breeding pairs or 42.2–42.7% of the global population (Karyakin, 2020). In the beginning of the 21st century, the Imperial Eagle was not so rare on nesting in Western Betpak-Dala, with at least 20 pairs recorded here (Karyakin, Barabashin, 2006; Karyakin et al., 2008; Gubin, 2018). B.M. Gubin (2018), summarizing his data on Western Betpak-Dala, reports 60 known inhabited nests of Imperial Eagles, 39 of which were located on the poles of high-voltage power lines and 21 on saxaul; the birds nested most densely between Taikonur and the water station that supplies water to Stepnoi settlement. By 2018, a minimum of 18 breeding territories of the Imperial Eagle were recorded in the Chu Valley and the area from Shu to Taikonyr (Karyakin, Barabashin, 2006a; Karyakin et al., 2008; Gubin, 2018; Abdullin et al., 2020; Andreenkov et al., 2020). A large group of the species is still present in southern Kazakhstan. In the last two years, research has been conducted and the population size of the Imperial Eagle has been revised along the edge of the Moiynkum sands in forest belts, where eagles of this species have not been monitored before. A large breeding group of more than 100 pairs is concentrated in the Moiynkum sands, which forms the southeastern edge of the desert population of this species (Karyakin, 2020). During two research seasons (2022 and 2023), it was possible to collect characteristics of 49 nests of the Imperial Eagle. Most nests (85.71%) were found on the Chinese Elm (Ulmus parvifolia), 6.12% on Turanga (Populus sp.), 4.08% on saxaul (Halóxylon sp.) and one nest each or 2.04% were recorded on Elaeagnus (Elaeagnus sp.) and electric poles (n=49). In 2022, clutch sizes ranged from 1 to 3 eggs, averaging 2±0.63 eggs per successful nest. The obtained data correlate with generalized data from literature sources. The research in 2022 (in 2023, research was conducted only in spring) showed satisfactory breeding success of the Imperial Eagle in the area under examination – 40% of successful nests, by the end of the season brood size ranged from 1 to 2 fledglings, averaging 1.75±0.5 fledglings per successful nest (n=4) and 0.78±0.97 fledglings per active nest (n=9). The overall breeding success for all nests examined was 44.44% and breeding efficiency was 58.33% (Karyakin et al., 2023). Despite the depression of the rodent population, imperial eagles are quite efficient in reorganizing to feed on different bird species and use other food items among mammals (hares Lepus sp., hedgehogs Erinaceus sp., etc.). The Imperial Eagle does not breed in the Talas Alatau (Kovshar, 1966, 2019), but is observed on migration (Chalikova, 2004; 2009; Kolbintsev, 2007; Karyakin et al., 2021). Moving eastward, to the Pribalkhashie, we can notice that the density of the species decreases. Modern finds of Imperial Eagle nests in the Southern Pribalkhashie indicate that the Imperial Eagle remains a characteristic breeding species here, but does not form dense breeding groups (Karyakin, 2020). In the east of Balkhash and on the plain to the west and south-west of Lake Alakol, the Imperial Eagle becomes rarer on breeding grounds. The results of the 2023 research in the south-east of the country indicate the absence of imperial eagles in the northern foothills of the Dzungarian Alatau and in the southern foothills of Tarbagatai. Only one case of breeding of a “mixed pair”, a female Imperial Eagle and a male Steppe Eagle (Aquila nipalensis), was recorded. Unfortunately, breeding was not successful. On the foothills plain, only single pairs of imperial eagles penetrating from the sands of the Southern Pribalkhashie nest in trees in artificial forest plantations and on power towers, distancing themselves usually more than 7 km from the other pair. In the 21st century, adult Imperial Eagles have not been observed anywhere else in the foothills of the Ketmen, Kungey Alatau and Zailiyskiy Alatu Mountains during the breeding season and their nests have not been found. As of 2018, the number of Imperial Eagles in Almaty Region was estimated at 20–40 pairs, and in Zhambyl and Turkestan Regions at 90–140 pairs (Karyakin, 2018). Given the number of known breeding territories, taking into account the literature and data from the datasets, it can be assumed that the population estimate is grossly understated for the Almaty Region, and the lower limit of the population estimate is understated for the Zhambyl and Turkestan Regions (Karyakin, 2020). There are a number of threats that affect the viability of imperial eagles in Kazakhstan. The main threat to the southeastern population of this species is the lack of food base. For several years now, there has been a depression in rodent population in southern and southeastern Kazakhstan, affecting all species from the Great Gerbil (Rhombomys opimus) and the Yellow Ground Squirrel (Spermophilus fulvus) to voles (Microtus socialis and Alticola argentatus) (Karyakin et al., 2022). Zoologists and locals have observed rodent depression since 2017. Another threat may be the degradation of imperial eagle habitats associated with both climatic and anthropogenic changes. For many years and even decades, the threat of dying of birds on power lines has persisted. This threat is particularly immediate because a significant proportion of imperial eagles nests on electric poles, where tree plantations are scarce, mainly along roads. In addition to the fact that birds die from collision with electric poles, from electrocution, there is a problem of nests being thrown off electric poles by employees of power companies during repair works or scheduled maintenance of power lines. Despite the many negatives affecting the Imperial Eagle, the situation with the Imperial Eagle is much better than with the Steppe Eagle, which has almost completely disappeared in the mountainous and foothill areas of Southeast Kazakhstan and has significantly reduced its numbers in the plains. The solution of the problem of bird deaths on power lines and the dropping of eagle nests from power lines would contribute to a greater survival rate of the Imperial Eagle and help it to survive the global depression of rodent numbers in Southeast Kazakhstan with fewer losses.
46
Arkhipov, Y., and J. Becker. "Eagles in the Burabay State National Natural Park." Raptors Conservation, no. 2 (2023): 153–56. http://dx.doi.org/10.19074/1814-8654-2023-2-153-156.
Full textAbstract:
From August 20 to September 17, 2022 and in the spring of 2023, the authors conducted ornithological research in the State National Natural Park “Burabay”. In the course of the research, information was obtained on encounters with eagles in the territory of the park. Imperial Eagles (Aquila heliaca) were observed throughout the area on a daily basis. A total of 44 observations were recorded during the research period, some of which were definitely migrants rather than local breeding birds. Only four out of 44 individuals observed were this year's birds. To the northeast of Big Chebachee Lake on 14/09/2022, adult birds were feeding a nestling, indicating the presence of a breeding territory of eagles here. In April 2023, a nest with two eggs was found. A large eagle nest, presumably of the Golden Eagle (Aquila chrysaetos), was found in the forest north of Zhukey Lake in the 40th district on September 6, 2022. The nest was located on an old pine tree and was approximately 1.5 m in diameter. Bone remains of prey and feathers of various birds of prey (e.g. Buzzards Buteo buteo) were found under the nest. Shortly afterwards, an eagle, identified by us as this year's Golden Eagle, wasseen in the vicinity of the nest, and on 13/09/2022 an adult bird was observed between the lakes Maloye Chebacheeand Bolshoye Chebachee, north of Lake Maibalyk. An adult Greater Spotted Eagle (Aquila [Clanga] clanga) was observed near the Kairaktin Forest District on 26/08/2022. The bird was carrying food in its beak to a juvenile bird calling from the forest (Becker/ebird.org; Wassink, 2023). This is the first case of breeding of the Greater Spotted Eagle in the State National Natural Park «Burabay». Another juvenile bird, uncertainly identified as the Great Spotted Eagle, was seen a few hours later about 12 km south of the previous encounter site. The Steppe Eagle (Aquila nipalensis) was observed twice, once on 25/08/2022 in Saule aul and once on 05/09/2022 over Ulkensor Lake. Steppe eagles are likely to be migrants or nomads within the Park after the breeding season, but do not breed in the Park. The Booted Eagle (Hieraaetus pennatus) was observed four times, on August 22 and 23 in the territory of Barmashinskoye Forestry, and on September 8 and 15, 2022 in the vicinity of Borovskoye Forestry, with birds of both light and dark morphs (Becker/ebird.org). In addition, on 21/07/2021, the Booted Eagle was recorded by a trap camera set up in the forest between Burabay and Sarybulak (Wassink, 2023). The nearest known breeding territory is located approximately 430 km to the southeast in Bayanaul National Park (Reznichenko, 2012; 2020). Proposed measures for the conservation of the considered bird species on the territory of the State National Natural Park «Burabay»: – introduce a ban on any logging within a radius of 1.5 km from eagle breeding territories; – sanitation cutting, with mandatory reforestation of native tree species, only after nestlings have learned to fly; – limit the presence of livestock and people within 500 m of eagle nests during the breeding season; – during the incubation period and before fledglings take wing, inspectors should conduct daily rounds of the breeding areas (within 500 meters of the nests) to prevent possible violations by park visitors; – restrict watering of livestock on the banks of water bodies near eagles' nests.
47
Pribadi, Dharmawan Pandu. "Studi Populasi Elang Jawa (Spizaetus bartelsi Stresemann, 1924) di Gunung Salak, Taman Nasional Gunung Halimun – Salak." BIOMA 10, no. 1 (March 30, 2014): 17. http://dx.doi.org/10.21009/bioma10(1).3.
Full textAbstract:
Abstract
Javan Hawk – Eagles is an endemic raptor species in Java Island which is protected by the state and listed as endangered by IUCN and CITES Appendix II. The population of Javan Hawk - Eagles has been greatly reduced due to large-scale of illegal logging and forest destruction. The initial step that could be taken to preserve this species is to study the population in its natural habitat. Thus, studying the population of Javan Hawk - Eagles was the aim of this research. The research was conducted at Gunung Salak, Gunung Halimun – Salak National Park in February to March 2011. Method used was explorative descriptive with look-down method on particular. Data were analyzed descriptively by describing the species’ distribution map by using ArcGIS and ArcView GIS 3.3 softwares. The results showed that the eagle population consisted of 13 individuals with density and abundance values of 0.183 individuals/km2 (1 individual/6 km2) and 2. The values fell into “few category” and the distribution pattern was categorized as “uniform”. The eagles’ habitats were forest and hills at 797-1.383 meters above sea level although they are seen more often in forest.
Key words: Gunung Salak, Javan Hawk – Eagles, population
48
Warner, Sarah E., Edward E. Britton, Drew N. Becker, and Michael J. Coffey. "Bald Eagle Lead Exposure in the Upper Midwest." Journal of Fish and Wildlife Management 5, no. 2 (May 1, 2014): 208–16. http://dx.doi.org/10.3996/032013-jfwm-029.
Full textAbstract:
Abstract In 2012, we examined lead exposure in 58 bald eagles Haliaeetus leucocephalus found dead in Iowa, Minnesota, and Wisconsin. We determined lead concentrations in livers, examined differences in exposure among ages and between sexes, and recorded clinical signs consistent with lead poisoning. Most (60%) of the bald eagles had detectable lead concentrations, and 38% of the 58 had concentrations within the lethal range for lead poisoning. We found no differences in exposure based on sex or age, but we did find an inverse relationship between body and liver mass and liver lead concentration. The high percentage of lead-exposed bald eagles encouraged us to further examine potential sources of lead in our local environment. We initiated a study on the Fish and Wildlife Service's Upper Mississippi River National Wildlife and Fish Refuge to investigate if discarded offal piles from hunter-killed deer were a potential source of lead exposure to scavenging wildlife such as the bald eagle. Radiographs showed that 36% of offal piles in our sample area contained lead fragments ranging from 1 to 107 particles per pile. Our study indicated that 1) lead exposure rates for bald eagles found dead in our Upper Midwest study area were high, 2) more than one-third of the bald eagles found dead in Iowa, Minnesota, and Wisconsin had liver lead concentrations consistent with lead poisoning, and 3) discarded offal piles from deer shot with lead ammunition can be a potential source of lead exposure for bald eagles.
49
Mayrose, A., E. Haviv, O. Hatzofe, W. Neser, D. Troupin, M. Elroy, and N. Sapir. "Pulling the Plug on Eagle Electrocution in Israel: High-resolution Modelling of Bonelli’s Eagle Electrocution Risk." Raptors Conservation, no. 2 (2023): 370–73. http://dx.doi.org/10.19074/1814-8654-2023-2-370-373.
Full textAbstract:
The Bonelli’s Eagle (Aquila fasciata) is a critically endangered species in Israel, with electrocution on power lines posing a serious threat on its population. Since insulation of electricity pylons is a slow and costly process, it is important to prioritize the insulation of the pylons in the network for quick and efficient mitigation of eagle mortality. To determine which pylons need to be retrofitted, we applied a three-stage Maximum Entropy Modeling process for identifying the risk factors among different environmental variables. The results show that the environmental feature with the highest correlation to electrocution events is the distance to water reservoirs, which are foraging hotspots of the eagles in Israel’s arid environment. Unfortunately, the only tall perch available for eagles in the vicinity of many of the reservoirs are the electricity pylons that power the reservoirs’ pumping facilities. This combination of anthropogenic alterations has apparently created a detrimental ecological trap. The strong attractiveness of water reservoirs for the eagles may explain the high level of selectivity that was calculated by the model, suggesting that retrofitting only 3.6% of the pylons in the network would achieve 77% reduction in eagles’ electrocution probability. Moreover, insulating pylons according to the model is expected to achieve a significant remedy for other avian species, among them the Eastern Imperial Eagles (Aquila heliaca) and White-Tailed Eagles (Haliaeetus albicilla). Synthesis and applications: The modeling process presented here yielded two electrocution risk maps, one of which is expected to facilitate properly prioritized mitigation of eagle electrocution in the existing power network of Israel, while the second map is designed to support an informed planning of new infrastructures. Applying this approach is expected to substantially aid the conservation of the population and allow it to recover to its initial size, which was three times its current size, about 70 years ago. The work presented here aims to prioritize the mitigation of raptor electrocution in arid and semi-arid areas, geographic zones that are largely under-studied in relation to this mortality factor. Electrocution in arid areas is of a particular concern in many developing countries, where networks of distribution lines are rapidly growing and raptor electrocution rate is high. The modeling approach presented in this study can be applied in these arid developing countries to mitigate raptor electrocution, aiding their conservation.
50
Shaffer, J. A. "Golden Eagles in the United States of America: Threats and the Federal Response to Potential Impacts from Renewable-Energy Development." Raptors Conservation, no. 2 (2023): 425–27. http://dx.doi.org/10.19074/1814-8654-2023-2-425-427.
Full textAbstract:
Golden Eagles (Aquila chrysaetos) have a Holarctic distribution. The subspecies A. ch. сanadensis inhabits North America, where it encounters the same anthropogenic threats as other eagle species worldwide, including electrocution on powerlines, shooting, collisions with vehicles, and poisoning by lead and rodenticides. A more recent threat is mortality from collisions with wind turbine blades. For the 11 States that are west of the 100th meridian and that represent most of the species’ year-round range within the coterminous United States of America (USA), over 600 individuals per year die from collisions with vehicles, wind-turbine blades, electrical power lines, and trains. Federal laws, policies, and guidelines aim to protect the Golden Eagle from the increasing threat of turbine mortality. Two Federal laws–the Migratory Bird Treaty Act and the Bald and Golden Eagle Protection Act–will be reviewed. The term “take”, which is defined as “pursue, shoot, shoot at, poison, wound, kill, capture, trap, collect, molest, or disturb” individual eagles, their parts, nests, or eggs will be further discussed. Within the U.S. Department of the Interior, the U.S. Fish and Wildlife Agency issues guidelines and regulations aimed to protect Golden Eagles from “take” and to set thresholds for that “take.” Guidelines and policies particularly relevant to wind-energy development include the Land-Based Wind Energy Guidelines, the Eagle Conservation Plan, and the Mitigation Policy. Each of these guidelines and policies will be explained. Federal mitigation policy has a 3-tiered strategy summarized as “Avoid–Minimize–Mitigate.” Practices that exemplify each tier of the “Avoid–Minimize–Mitigate” strategy will be examined, including such practices as avoiding sites deemed of highest risk to cause harm, minimizing harm by such activities as turbine curtailment, and mitigating unavoidable “take” by engaging in mitigation banking. Currently, the only compensatory mitigation practice authorized by the U.S. Fish and Wildlife Service is the retrofitting of power poles. Thus, the Bald Eagle and Golden Eagle Electrocution Prevention In-lieu Fee Program, which retrofits power poles deemed of high-risk in causing electrocution of eagles, will be discussed. Other mitigation options worthy of consideration for future authorization also will be described.