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1
Bozó, László, Yury Anisimov i Tibor Csörgő. "Association of weather variables with the migration phenology and body conditions of Siberian warblers". Ornis Fennica 98, nr 4 (14.01.2022): 162–74. http://dx.doi.org/10.51812/of.113447.
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Different elements of weather, such as wind speed, wind direction, precipitation and temperature are very important regulators of bird migration. Weather conditions also play role on the body condition such as body mass and the deposited fat. In this study we selected four warbler species to examine the impact of different weather variables on their spring and autumn migration timing and their body condition in one of the most extreme weather areas of the Earth, at Lake Baikal in Siberia. We also studied the changes in body mass and fat reserves during the spring and autumn migration periods of these species. For the analyses, we used ringing data of 2471 birds from five spring and five autumn seasons during 2015–2019. According to our results, it can be stated that the weather did not have a significant association with the migration timing of the studied warblers, perhaps due to the geographical location of the study site. However, the body mass and the fat reserves of the birds increased during unsuitable weather conditions because of the increased energy requirements. Birds generally migrate with low fat reserves, which is due to the fact that this area is not an important stopover site for these species.
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Beal, Martin, Patrik Byholm, Ulrik Lötberg, Tom J. Evans, Kozue Shiomi i Susanne Åkesson. "Habitat selection and foraging site fidelity in Caspian Terns (Hydroprogne caspia) breeding in the Baltic Sea". Ornis Fennica 98, nr 4 (14.01.2022): 182–41. http://dx.doi.org/10.51812/of.113445.
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Habitat preferences and foraging strategies affect population-level space use and are therefore crucial to understanding population change and implementing spatial conservation and management actions. We investigated the breeding season habitat preference and foraging site fidelity of the under-studied and threatened, Baltic Sea population of Caspian Terns (Hydroprogne caspia). Using GPS devices, we tracked 20 adult individuals at two breeding colonies, in Sweden and Finland, from late incubation through chick-rearing. Analyzing foraging movements during this period, we describe trip characteristics for each colony, daily metrics of effort, habitat use, and foraging site fidelity. We found that daily time spent away from the colony increased throughout the season, with colony-level differences in terms of distance travelled per day. In general, terns selected shallow waters between 0–5 meters in depth with certain individuals using inland lakes for foraging. We show, for the first time, that individual Caspian Terns are faithful to foraging sites throughout the breeding season, and that individuals are highly repeatable in their strategies regarding foraging site fidelity. These results fill important knowledge gaps for this at-risk population, and extend our general knowledge of the breeding season foraging ecology of this widespread species.
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Ludwig, Tobias, Ralf Siano i Alexander V. Andreev. "Habitat selection of sympatric Siberian Grouse and Hazel Grouse in natural and exploited forests of the lower Amur region". Ornis Fennica 98, nr 4 (14.01.2022): 142–61. http://dx.doi.org/10.51812/of.113446.
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The Siberian Grouse (Falcipennis falcipennis), which is endemic to the “dark-needle” taiga of the Russian Far East, is one of the least studied grouse species in the world. We examined post-breeding habitat selection of Siberian Grouse and contrasted it with that of the better examined Hazel Grouse (Tetrastes bonasia) in two areas near Komsomolsk na Amure, Russia. To infer species-specific preferences, we used field sampling, logistic regression, and AIC model selection, and compared late summer habitats of Siberian Grouse and Hazel Grouse in a mountain- and hilly area in the dark needle taiga. Our study is the first to explain Siberian Grouse habitat relationships with an empirical modelling approach. Results indicate proportions of coniferous/ pioneer trees forest and rejuvenation to be the most important covariates separating Siberian and Hazel Grouse observation sites in forests from both areas. Siberian Grouse tended to select sites with low proportions of pioneer trees and rejuvenation but availability of dwarf shrubs. Bunchberry (Cornus canadensis) appeared to be of high importance for the presence of Siberian Grouse in both regions. Hazel Grouse were common in places dominated by pioneer trees with high canopy cover, and high proportions of grass/herb cover. Hazel Grouse also occurred more often in forest sites with dense vertical layering and rejuvenation. Modern forestry, which results in increasing amounts of forests at younger successional stages, is likely to favour the Hazel Grouse at the expense of the Siberian Grouse.
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Mokhberolsafa, D. "Instructiebevoegdheid en de aansprakelijkheid van de moedervennootschap als medebeleidsbepaler van haar dochter-bv op grond van art. 2:248 lid 7 BW: een kwestie van balans". Onderneming en Financiering 22, nr 2 (czerwiec 2014): 5–23. http://dx.doi.org/10.5553/of/157012472014022002002.
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Pleiter, H. R. "Het enquêterecht en het toetsen van besluiten in arbitrage". Onderneming en Financiering 22, nr 2 (czerwiec 2014): 24–37. http://dx.doi.org/10.5553/of/157012472014022002003.
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Caria, V. Y. E. "De (bijzondere) zorgplicht van banken jegens ondernemers bij renteswaptransacties". Onderneming en Financiering 22, nr 2 (czerwiec 2014): 38–54. http://dx.doi.org/10.5553/of/157012472014022002004.
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van Borssum Waalkes, J., i E. van der Schans. "Prijs- en waardebepaling van aandelen in besloten vennootschappen in ondernemingsrechtelijke procedures". Onderneming en Financiering 22, nr 2 (czerwiec 2014): 55–73. http://dx.doi.org/10.5553/of/157012472014022002005.
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Ruuskanen, Suvi. "New Editor-in-Chief". Ornis Fennica 94, nr 1 (31.03.2017): 1. http://dx.doi.org/10.51812/of.133906.
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Manikowska-Ślepowrońska, Brygida, i Włodzimierz Meissner. "Factors affecting apparent survival and resighting probability of wintering mallards Anas platyrhynchos". Ornis Fennica, 22.09.2022, 00. http://dx.doi.org/10.51812/of.121697.
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Survival of adults is a key demographic parameter affecting avian population dynamics. In urban areas, e.g., city parks, birds stay in winter in large numbers where they have access to a multitude of food sources due to human activities, which is one of the key factors that attract birds into the cities. Our study estimates apparent survival of mallard ducks Anas platyrhynchos between non-breeding seasons in a small town in the coldest region in north-eastern Poland between 2005 and 2017. We found lower survival estimates for females (juveniles: 0.54; adults: 0.59) than males (juveniles: 0.76; adults: 0.72) and probabilities of resighting individuals in the next non-breeding season were higher if the bird was resighted in the study area during the prior breeding period. Thus, we conclude that sedentary mallards from the local urban population have relatively high survival, which may be explained by lower pressure from raptors, lack of hunting and higher winter temperatures in the urban site. Additionally, winter temperature was negatively related to resighting probability in the next non-breeding season. Resighting probability was time-dependent with a bimodal pattern with maximal estimates of 0.48 in 2007/2008 and 0.98 in 2013/2014, 0.98 in 2014/2015, 1.00 in 2015/2016. These results are most likely related to volunteers’ activity that increased due to organized official competition with special awards during those seasons. Considering the fact that the type of ring (metal or plastic coloured) significantly influenced the probabilities of resighting of individuals, it is recommended that apparent survival studies on birds be conducted using colour rings. Moreover, we encourage to collect more capture-mark-recapture data to enable accurate estimations of duck survival, which not the least is a prerequisite for successful management and conservation efforts.
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Zyśk-Gorczyńska, Ewa, i Michał Żmihorski. "Ultraviolet film reduces bird–glass collision risk". Ornis Fennica, 24.09.2022, 00. http://dx.doi.org/10.51812/of.115995.
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It is estimated that millions of birds globally die due to collisions with glass surfaces. In order to reduce this mortality, it is essential to provide an objective assessment of the effectiveness of bird-friendly preventive methods. Several types of opaque films and stickers are available nowadays and can be highly effective in protecting birds from fatal collisions. However, by being visible to the human eye, they can affect the users’ quality of view from within protected spaces. Products that take advantage of the birds' ability to see ultraviolet light seem to offset these impediments. This study determines if UV-reflective BirdShades film prevents birds from collisions with glass in natural environmental conditions. We monitored eight glass bus stops, where we had previously recorded high numbers of birds collisions. On four of them, we applied UV film, and the other four bus stops were used as control. A generalized additive mixed model showed a significant interaction between time (before vs. after) and film UV treatment (control vs. treated). Before the treatment, the number of collisions tended to be higher at treated bus shelters than control. However, this significantly changed after the treatment, suggesting that UV film reduces bird glass collision rate over 5-fold. Our study is the first worldwide that tested UV film on glass shelters and supports a conclusion that the UV film efficiently reduces the risk of bird collision.
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Schally, Gergely, Sándor Csányi i Péter Palatitz. "Spring migration phenology of Eurasian Woodcocks tagged with GPS-Argos transmitters in Central Europe". Ornis Fennica, 5.10.2022, 00. http://dx.doi.org/10.51812/of.121933.
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Eurasian Woodcock (Scolopax rusticola) plays a special role in the cultural heritage of most nations in Europe. In the last decade, ringing revealed the main migratory patterns of some well studied and intensively harvested Woodcock populations wintering in Western and Southern Europe. The same study sites and populations were in focus when the recently revolutionized satellite tracking technologies allowed the study of individual migrations. In contribution to these efforts, we present here the pre-nuptial migration data of Woodcocks captured and tagged with GPS-Argos transmitters in Central Europe, in 2020. Woodcocks migrated from the tagging site in Hungary to Ukraine, European Russia and Central Siberia by an average of 2,678 km (range 677–5,002 km). The duration of the migration ranged between 1–52 days, the overall migration speed was 382 km/day, the absolute maximum distance covered in a day was 866 km. The individual number of stopovers varied during the migration from 0 to 5. The average time spent at each stopover site was 5.6 days. Within the stopover sites, the daily displacements ranged between 11–3,329 m. The Carpathian Basin may be more important in the wintering of Woodcocks than previously assumed, as tagged birds stayed significantly longer compared to any later en route migratory stopover. In accordance with the results of previous DNA analysis, identified breeding grounds of tagged individuals represented a large part of the distribution area.
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Milchev, Boyan. "Diet shifting of tortoise-eating Golden Eagles (Aquila chrysaetos) in southeastern Bulgaria". Ornis Fennica, 2.09.2022, 00. http://dx.doi.org/10.51812/of.121253.
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Top predators may adapt their diets to changes in prey availability where human-induced environmental changes are intense. This long-term study of the breeding-season diet of Golden Eagle (Aquila chrysaetos) in the Strandzha Mountains analyzed shifts in diet caused by the population decline in principal prey species, the tortoises (Testudo hermanni and T. graeca). Tortoises comprised 50.0% of the eagle diet by prey number in the 1990s, but that share collapsed to 5.8% in 2014–2021. During this later interval, Golden Eagles preyed more intensively on lighter-weight prey such as Northern White-breasted Hedgehog (Erinaceus roumanicus, an increrase of 28.2% by number) and Edible Dormouse (Glis glis, an increase of 14.9% by number). Hedgehogs predominated in the diet of an individual eagle nest site for the first time in 1998 and became the principal prey in 2014–2021. Differences in food niche breadth and proportions of mesopredators between tortoise- and hedgehog-dominated individual annual diets were not significant, corresponding to a low level of food stress. The only eagle with an annual diet dominated by Squamata (snakes and lizards) was an exception, having the widest food niche. Young domestic ungulates have almost completely disappeared from eagle diets at the same as the reduction of tortoises, corresponding to a concurrent decline of livestock farming. The results obtained here have relevance to conservation management of both predator and prey populations.
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Vaskuti, Éva, Sándor Zsebők i László Garamszegi. "Tutoring new song elements to male birds in the wild". Ornis Fennica, 2.08.2022, 00. http://dx.doi.org/10.51812/of.120666.
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Many vocalisations of songbirds are sexually selected and socially learnt behavioural traits that are subject to cultural evolution. For cultural inheritance, it is required that individuals imitate the song elements and build them into their repertoire, but little is known about how such learning mechanisms take place in natural populations of birds with large repertoire size. Using a Hungarian population of the collared flycatcher (Ficedula albicollis) as a model, we tested how often adult males can build new song elements (artificially modified or originated from distant populations) into their repertoire during mating season by using a playback approach. We predicted that when individuals incorporate new elements into their repertoire, the formerly unfamiliar elements from the playback songs would be recovered in the recorded songs of the focal males. We performed a teaching procedure with 26 males, in which we played back song sequences containing three artificially modified and three foreign syllables for each male. We recorded the song of the focal males twice a day for 2–6 days long. Then, we applied a thorough search based on a combined automatic and manual identification method to detect the tutorial syllables in the recorded songs. We found one foreign syllable type in the recordings from one male which indicates that male collared flycatchers may learn new syllable types in the courtship season. As our study has some limits, we highlight some general challenges concerning the use of playback approaches in the field for demonstrating the incidences of learning of particular song elements.
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Bregnballe, Thomas, Peter Sunde i Kevin Kuhlmann Clausen. "Occurrence of rats and their impacts on colonial waterbirds in a Danish fjord". Ornis Fennica, 6.07.2022, 00. http://dx.doi.org/10.51812/of.120259.
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Human development around the globe has led to great expansion of the Brown Rat (Rattus norvegicus), which has implications for local wildlife and especially ground-breeding birds. In this study, we analyse the colonisation and persistence of rats on small islets important to breeding waterbirds in a Danish fjord, and investigate the effect of rat presence on the number of breeding pairs of eight waterbird species. The islets had an annual rat colonisation probability of 6% and an annual rat population persistence rate of 65% (equalling an annual population survival rate of 62% when adjusting for re-colonisations upon extinctions). Contrary to our hypotheses, rat colonisation and persistence was uncorrelated with islet size, distance from the mainland and the presence of shrub cover. Rat presence had a significant negative effect on the number of breeding pairs of four waterbird species, including Avocet (Recurvirostra avosetta, reduced to 30% compared to years without rats), Black-headed Gull (Chroicocephalus ridibundus, reduced to 45%) and Common Tern (Sterna hirundo, reduced to 52%). The smaller bird species in particular seemed to be affected by the presence of rats, and control efforts aimed at reducing rat presence on important breeding bird islets may consequently have a positive effect on the occurrence and breeding success of these species. We found no evidence of birds acting on a memory of where rats had been present in the previous year, and further research is needed to investigate the precise mechanisms behind the recorded negative effects in the contemporary year, i.e. how do prospecting as well as settled breeders detect and behaviourally respond to the presence of rats.
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Lehtonen, Pekka, i Jyrki Lappalainen. "Individual variation in song of Black-throated Divers (Gavia arctica)". Ornis Fennica, 17.05.2022, 00. http://dx.doi.org/10.51812/of.117869.
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The intention of the study was to determine whether male Black-throated Divers (Gavia arctica) can be distinguished individually by their vocalization. The songs of 19 male Black-throated Divers (BTDs) were recorded in their territories in the same lake area in 2018–2021 in Finland. The songs were recorded in one year in nine territories and in 2–4 consecutive years in ten territories. The song consists of one introductory phrase and one or more repeat phrases. Seventeen variables were measured from the spectrograms of the introductory phrase and the first repeat phrase. These variables included the frequencies and duration of different parts of the spectrogram. The discriminant analyses were used to examine the recognition of individual BTDs based on the spectral analysis of the male yodels (n = 297) in different territories (n = 19). The discriminant analysis showed that when using 14 of the variables of the yodels, the discriminant analysis classified the yodels to correct territories at a rate of almost 98% based on the cross-validation of all data. This suggests that the same individuals defend their territory from year to year.
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Heldbjerg, Henning, Anthony D. Fox, Thorsten J. S. Balsby i Peder V. Thellesen. "Night-brooding behaviour in provisioning cavity-nesting birds is a trade-off between adult predation risk and nestling thermoregulation needs". Ornis Fennica, 20.05.2022, 00. http://dx.doi.org/10.51812/of.117871.
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Night-brooding of nestlings in cavity-nesting avian species carries predation risks to parents. Anecdotally, several species are known to shift from constant adult night-brooding behaviour to leaving nestlings unattended at night during offspring development but the timing, speed of change and sex-specific differences between parents, and the factors shaping this behaviour have rarely been described. Moreover, the location and nature of night roosts used by adults whilst provisioning nestlings has received little research attention. We studied breeding Common Starlings Sturnus vulgaris and hypothesised that, in such a cavity-nesting species, 1) nestlings would only be night-brooded until they achieved thermal independence, 2) since the species is frequently polygynous, female parents would most likely exclusively night-brood offspring despite provisioning by both sexes and 3) night-brooding would be more likely during nights with lowest temperatures. Nightly video recordings throughout the nestling phase at eight Starling nests together with data from 18 Starlings fitted with GPS-loggers during 26 nights provided support for hypotheses 1) and 2), while we found no support for hypothesis 3). All tagged male Starlings always roosted far from the nesting site (up to 8 km) independent of nestling age; all females brooded nestlings, usually up to the first seven-nine days after hatching (when the nestlings achieve thermoregulation), but roosted with males after day 10, when all tagged Starlings from the same nesting ‘colony’ roosted together. These results confirm differential sex-related parental effort in provisioning Starlings, suggesting females only night-brood until young achieve homeothermy.
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Bustnes, Jan Ove, Morten Helberg i Bård-Jørgen Bårdsen. "Reproductive success of threatened northern Lesser Black Backed Gulls (Larus fuscus fuscus) in relation to nest predation by Ravens (Corvus corax)". Ornis Fennica, 4.03.2022, 00. http://dx.doi.org/10.51812/of.115081.
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Many seabird populations suffer heavily from the destruction of nests by generalist predators. In this study, we analyzed 16 years of data (2005–2020) on the reproductive output of the northern Lesser Black-backed Gull (Larus fuscus fuscus) at Horsvær, the largest assemblage of this subspecies in Norway (up to ca. 400 pairs), in relation to the occurrence of breeding Ravens (Corvus corax). A pair of Ravens were firstly discovered at Horsvær in 2010, and between 2011 and 2016 they were observed with broods (2–5 fledglings) in most years. Between 2017 and 2020, human intervention prevented the Ravens from breeding in the colony. However, in 2020 a pair of Ravens brought their fledglings over from a neighboring island in the middle of the incubation period for the gulls. On average, the nest predation rate was 43% when Ravens had fledglings within the study area. In contrast, only 10% of nests were depredated in years when Ravens did not reproduce successfully or were absent. Moreover, only 0.07 fledglings were on average produced per nest in years when Ravens bred successfully, compared to 0.71 fledglings per nest in years with no Raven reproduction. A high level of nest predation led to a decline in the number of nesting gulls, which was not observed in a neighboring Raven-free colony. Finally, in years with high Raven predation at Horsvær, production of fledglings was still high in yet another nearby Lesser Black-backed Gull colony. The Ravens were established at Horsvær in the absence of people in the spring, and the only option to save these threatened gulls may be to prevent the Ravens from nesting successfully in or near their colonies.
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Teräväinen, Malin, Johan Elmberg, Carina Tennfors, Olivier Devineau, Karen-Marie Mathisen i Johan Månsson. "Field selection of greylag geese (Anser anser)". Ornis Fennica, 20.09.2022, 00. http://dx.doi.org/10.51812/of.115136.
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Greylag geese (Anser anser) have been increasing in numbers in Europe during the last decades. They forage and roost in agricultural landscapes and may cause damage to sensitive crops. We studied field selection of greylag geese around lake Sörfjärden in south central Sweden where geese aggregate during the growing season. In this area a set-aside field was established in 2010, i.e., a field where geese can graze undisturbed, with the aim to reduce damage in surrounding conventional fields. The goal of our study was to investigate the general selection of the different field types as well as the specific set-aside field. We used a point survey count to estimate goose numbers and regression analyses to evaluate the relationship between presence or absence of greylag geese and field characteristics such as crop type, distance to roost site and field size. According to the top-ranked model, the probability of presence of foraging greylag geese was higher in spring and in grass fields, while the probability decreased with distance to roost site. Our results also show that the set-aside field in general was used more than other fields in the area during spring and summer but not during autumn. We conclude that it is important to consider variables affecting the probability of field selection by geese, such as season, crop type and distance to roosts to understand the behaviour of geese when establishing set-aside fields.
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"Voorwoord". Onderneming en Financiering 22, nr 2 (czerwiec 2014): 3–4. http://dx.doi.org/10.5553/of/157012472014022002001.
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Engler, Marc, i Oliver Krone. "Estimating the onset of natal dispersal for a large diurnal raptor: A methodological comparison". Ornis Fennica, 2.02.2023, 00. http://dx.doi.org/10.51812/of.115528.
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We estimated the onset of natal dispersal for a large diurnal raptor with high propensity towards large-scaled exploratory movements during the post-fledging period, the White-tailed Sea Eagle (Haliaeetus albicilla). We analysed GPS tracking data of 21 juveniles with respect to the onset of natal dispersal comparing six methods available from the recent literature. While none of the methods significantly differed from the visual method, the Distance Threshold method underestimated the dispersal onset for some individuals. Likewise, coefficient of variation methods overestimated the dispersal onset in few cases, presumably because the temporal scale of available GPS fixes did not correspond to the scale of discrete dispersal movements. We conclude that all tested methods are generally suitable to estimate the dispersal onset, specifically if the research question does not depend on an exact but rather a rough estimate. A visual determination might increase flexibility to account for individual behavior and yields consistent results across individuals, but highly reduces the comparability across observers and studies. For research questions relying on exact estimates, we propose using a combination of an automated method and a visual determination as a back-up method for single individuals with clear under- or overestimation. An exploratory comparison showed that the temporal resolution of the GPS may further affect the accuracy of natal dispersal estimates. For individuals with clear movement patterns, high-resolution movement data could increase the accuracy of Coefficient of Variation methods. We underline the necessity for further investigation on the effects of temporal resolution on dispersal onset estimates.
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Leprince, Raphaël, Etienne Debenest, Christophe Lartigau, Victor Turpaud-Fizzala, Cyrille Poirel, Nicolas Lachaussée, Marie Donnez i Pierrick Bocher. "Influence of habitat quality and diversity on two populations of Eurasian curlew (Numenius arquata) with contrasting dynamics in Western France". Ornis Fennica, 1.12.2022, 00. http://dx.doi.org/10.51812/of.124713.
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Like most shorebirds in Europe, breeding populations of Eurasian curlew (Numenius arquata) are suffering from habitat loss and degradation mainly caused by changes in agricultural practices. In Deux-Sèvres (France), the number of pairs has gradually declined since the early 2000s in the main, historical breeding site, while a new breeding site has appeared recently 80 kilometres further north with increasing number of pairs through the survey period. Many wheat fields and rare dry grasslands are found in the north, whereas the landscape in the south is mainly composed of tillage plots, hay meadows, and pastures. This study aims to highlight differences in food availability and quality between the two areas. Sample series of ground-dwelling and vegetation-dwelling invertebrates were carried out during three key stages of the species breeding cycle with pitfall traps and sweep nets. Dry grasslands in the north were found to be the most favourable habitat in terms of prey availability for adults and for chicks during the brood-rearing period. Moreover, hay meadows and pastures in the south seemed to be resource-abundant feeding habitats. Therefore, the habitats of the northern site seem to offer a greater abundance of invertebrates and thus a potentially larger food resource than the southern one. It follows that the northern site likely offers better breeding conditions, especially for the growth of chicks. An increase in the area of dry grasslands in the north and the establishment of adapted agricultural management in the south would be favourable for the conservation of local curlew populations.
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Pilacka, Lucyna, Grzegorz Neubauer, Natali Karlionova, Pavel Pinchuk i Włodzimierz Meissner. "Chick survival in a high-density Northern Lapwing (Vanellus vanellus) population on the river islets of the middle Pripyat River, Belarus". Ornis Fennica, 27.12.2022, 00. http://dx.doi.org/10.51812/of.124843.
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The field studies were conducted in three ephemeral river islets of the middle Pripyat River, southern Belarus in 2006–2007. Nestlings of the Northern Lapwing (Vanellus vanellus) were ringed soon after hatching, and reencountered during subsequent visits. Post-hatching survival was estimated by capture-mark-recapture models. Daily survival rates of the Northern Lapwing chicks were very high, varying between 0.90 and 0.99, and the cumulative survival rates over 35 days between hatching and fledging were 0.54 and 0.70 in 2006 and 2007, respectively. Survival rate was lower in the first ten days of life, which is similar to that reported in other precocial species. The key factor supporting this high breeding success is low predation due to nesting of lapwings on periodic river islets that naturally restrict access by mammalian predators and apparent scarcity of terrestrial and avian predators. River islet habitats with co-occurrence of dry and wet fertile microhabitats provide optimum feeding conditions for the Lapwing chicks with a wide range of aquatic, ground and surface invertebrates. Moreover, semicolonial breeding of the Northern Lapwing (about 30 nests/ha) with other waders, terns and gulls increases the effectiveness of anti-predator behaviour. Consequently as a result of low predation pressure and good foraging conditions, in 2006 and 2007, productivity was 2.1 and 2.8 fledged young per single nest with four chicks respectively, a value hardly reported in Europe, except in managed sites.
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Thibault, Jean-Claude, Fabrice Torre, Ludovic Lepori, Christophe Panaïotis, Jean-Marc Pons, Jean-François Seguin i Alice Cibois. "Distribution and habitat of the Eurasian Treecreeper (Certhia familiaris) in Corsica". Ornis Fennica, 27.12.2022, 00. http://dx.doi.org/10.51812/of.114609.
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The Eurasian Treecreeper is a forest bird distributed from South-Western Europe up to Northern Asia. Two phylogenetic groups have been recently identified within this species, one restricted to Corsica Island (Mediterranean) and the Caucasus region, the other distributed over most of Eurasia and in Northern Asia. Little is known on the natural history of the Corsican population. We present here new comprehensive data on its distribution and habitat. The Eurasian Treecreeper is found from sea level to the upper limit of the forest but absent from the treeless macchia, a dominant vegetation in Corsica. Breeding occurs in a variety of tree species with a strong preference for mature stands and large trees. Its preferred habitat consists of old stands of Corsican Pines and of Sweet Chestnuts, although they are not the commonest tree species in Corsica. The current decline of Sweet Chestnut orchards confers a particular importance to the future preservation of mature stands of Corsican Pine, a patrimonial habitat of great value hosting several endemic bird taxa.
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García-Macía, Jorge, Javier Vidal-Mateo, Javier De la Puente, Ana Bermejo i Vicente Urios. "Spatial ecology of the Red Kite (Milvus milvus) during the breeding period in Spain". Ornis Fennica, 5.12.2022, 00. http://dx.doi.org/10.51812/of.124714.
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Studies focusing on the spatial ecology of the Red Kite (Milvus milvus) during the breeding season are scarce, despite this season having major importance in its conservation. Spain has one of the largest breeding populations of this species, but it is very threatened in this country. Here, 28 Red Kites were tagged in Spain with GPS satellite transmitters to study the movements of breeding adults during the breeding season (March-June), evaluating the differences according to sex, and investigating the habitat selection. The area used by females was smaller than the used by males (95% KDE = 4.48 vs. 3.30 km2). Females also traveled less distance per hour and remained closer to the nest. Thus, females had a higher frequency of locations at distances <250 m from the nest, while males had a higher frequency at distances >1 km. Distances recorded at >5 km were scarce for both sexes, and maximum distances reached were usually (61% of seasons) less than 15 km. Both sexes increased the frequency of movements between 1–3 km during the central hours of the day. Red Kites mainly used areas occupied by non-irrigated arable land, forests, scrubs, and herbaceous vegetation. The selection of certain types of crops highlights the importance of the agroforestry landscape for the conservation of the species. On the other hand, we documented for the first time how part of the Spanish breeding population is a short-distance migrant within the Iberian Peninsula while other part of the population makes post-breeding movements during summer.
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Hernández, Ángel. "Diet and grit characteristics in young Eurasian Bullfinches (Pyrrhula pyrrhula) inhabiting Iberian hedgerows". Ornis Fennica, 5.12.2022, 00. http://dx.doi.org/10.51812/of.124715.
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For the first time, the diet of young Iberian Bullfinches (Pyrrhula pyrrhula iberiae) is studied, specifically in a hedgerow habitat in northwestern Spain, through stomach (younger nestlings up to 8 d of age, which died without researcher intervention) and faecal sac (older nestlings) analysis, and secondarily direct observation (nestlings and dependent juveniles). Also, for the first time, grit use by bullfinch nestlings is described in some detail. Bullfinches fed their young with a mixture of seeds and invertebrates, with greater quantitative importance of the former. The identity of the seeds varied considerably between spring and summer, and animal fraction gradually decreased from May to July for older nestlings, in both cases presumably because of the seasonal changes in food availability. Caterpillars and spiders were the most important arthropod prey in the diet. Apparently, the young were not fed non-arthropod invertebrates. The relative importance of invertebrates, which are very rich in proteins, was greater for younger nestlings than for older ones. Difficult to digest hard-bodied prey, such as beetles, were not present in the stomachs of the youngest nestlings. The frequency of occurrence and amount of grit in stomachs increased with nestling age, along with the need to grind food. There were no remarkable differences in number of units, size, or number of colour types of gastroliths between months. The high floristic diversity in the study area, which has great overall conservation value, provides a wide range of resources for bullfinches, including plenty of food for their young.
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Stański, Tomasz, Marzena Stańska i Dorota Czeszczewik. "Foraging behaviour of the Great Spotted Woodpecker (Dendrocopos major) in the Białowieża National Park". Ornis Fennica, 3.02.2023, 00. http://dx.doi.org/10.51812/of.126163.
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Although the Great Spotted Woodpecker (Dendrocopos major) is the most common of the European woodpecker species, there are no studies detailing its foraging behaviour in the breeding and non-breeding seasons. Our research, conducted in the primeval oak-lime-hornbeam forest of the Białowieża National Park in 1999–2011, compared foraging sites and foraging techniques used by this species in these two seasons. Great Spotted Woodpecker predominantly foraged on standing trees, while lying trees and the ground were occasionally used as foraging sites, but almost exclusively in the breeding season. European hornbeam (Carpinus betulus) and small-leaved lime (Tilia cordata) were the most frequently used for foraging in the breeding season, whereas Norway spruce (Picea abies) and pedunculate oak (Quercus robur) were used in the non-breeding season. Great Spotted Woodpecker foraged more frequently on dead and large trees in the non-breeding season. In the breeding season, Great Spotted Woodpecker collected food mainly from living substrates, predominantly sites on large diameter trunks and at low height, while in the non-breeding season it collected food from thin, dead and upper branches. Searching for food and gleaning it from the tree surface was the most common foraging technique used in the breeding season, whereas seed extraction from cones dominated in the non-breeding season. The percentage of foraging time spent on this type of food was positively correlated with the index of Norway spruce seed production. Our study showed that the foraging behaviour of the Great Spotted Woodpecker in the two seasons differs significantly due to changes in food resources.
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Larsson, Kjell. "Age and sex ratios in the declining West Siberian/North European population of Long-tailed Duck wintering in the Baltic Sea". Ornis Fennica, 21.10.2022, 00. http://dx.doi.org/10.51812/of.113681.
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The West Siberian/North European population of Long-tailed Duck (Clangula hyemalis), which breeds in the Russian Arctic and northern Fennoscandia and winters in the Baltic Sea, has declined rapidly since the 1990s. To identify the causes of the decline and initiate effective conservation measures information on basic demographic parameters is needed. A photo survey method was used to estimate female age ratios and the proportion of males among adults in wintering Long-tailed Ducks at coastal and off-shore areas in the Baltic Sea. Female age ratios were defined as the number of first winter males, assumed equal to the number of first winter females, per adult female. Several thousand individuals were sampled each winter from 2008 to 2021. Female age ratios fluctuated between years and were consistently lower in the southern than in the central Baltic Sea. The proportion of males among wintering adults birds was male-biased, more so in the southern Baltic Sea than in other regions. A population model was used to analyse if low female age ratios between 2008 and 2021 has constrained population growth. Given that the estimated weighted mean female age ratio of 0.153 was representative at the population scale, an extremely high adult female mean annual survival rate of 0.872 would have been needed to maintain a stable population. Considering known sources of anthropogenic mortality in the Baltic Sea, and instead assuming a more realistic survival rate of ca. 0.80, a population decline of ca. 7.7% per year should have occurred during the study period.
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Bloche, Daniel A. F., Kasper Thorup, Kent Olsen, Per Ekberg, Peter Ellegaard Larsen, Knud-Erik Strange i Anders P. Tøttrup. "Breeding biology of Red-backed Shrikes (Lanius collurio): distribution, performance and post-fledging survival in Denmark". Ornis Fennica, 7.06.2023, 00. http://dx.doi.org/10.51812/of.124729.
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Agricultural intensification and habitat degradation across Europe have caused declines since the 20th century in populations of birds adapted to open landscapes, such as the Red-backed Shrike (Lanius collurio). Effective conservation strategies require knowledge on species’ breeding biology. To understand the status of the Danish breeding population better, we investigate which factors affect their breeding parameter (i.e. distribution, performance, post-fledging survival and behaviour). Our focus on the post-fledging period addresses present knowledge gaps due to the importance of this, yet under-studied, phase of passerines’ breeding cycle. We studied breeding pairs on different habitat types with Denmark-wide Citizen Science data, complemented by data of local projects in Northern Zealand and Northern Jutland (Denmark). Significantly fewer pairs were found in agricultural habitats and more in forests, semi-natural open habitats and synanthropic habitats. Pairs in forests had a significantly higher breeding productivity compared to agricultural or semi-natural open habitats for data from the years 2000 to 2021. Some project sites showed significantly higher number of fledglings compared to others, indicating that these sites are potential core areas for breeding productivity. Over the last two decades, the mean breeding productivity across Denmark was stable with 2.3 fledglings per successful pair. The survival rate of ringed fledglings increased during the post-fledging period, likely due to their increase in more active and independent behaviour. The relatively low breeding productivity found in this study calls for further studies including detailed data from potentially secondary habitats like agricultural areas to understand the effects of habitat on population fluctuations.
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Bordjan, Dejan, Alaaeldin Soultan i Klemen Jerina. "Temporal occurrence and species composition of birds on artificial feeding sites maintained for game mammals in the Dinaric Mountains, Slovenia". Ornis Fennica, 21.06.2023, 00. http://dx.doi.org/10.51812/of.121820.
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Artificial feeding is a widely used management tool, but it often attracts nontarget species, including birds, to permanent feeding sites. This study used camera traps to monitor the presence of birds at selected sites used for bear management in Dinaric forest. A large number of bird species (35) were recorded, representing roughly half of all species breeding in the surrounding area. These species were grouped based on monthly and hourly presence, and corresponded to food groups, with most belonging to granivores or scavengers. Some species, such as Pigeons (Columba sp.), Raven (Corvus corax) and Buzzard (Buteo buteo), adapted their presence to the availability of food at the feeding sites, while others were not affected by this. Both Chaffinches (Fringilla coelebs) and Jays (Garrulus glandarius) frequented the feeding sites, but their temporal presence was influenced by their biology rather than by food availability. The Sparrowhawk (Accipiter nisus) also adapted its presence to food availability, and its presence was closely associated with that of the Jay. This study confirms the temporal differences in the use of feeding sites by birds and mammals, which is likely due to their different biology and past management. This can be used to make wildlife management more efficient and reduce the undesirable effects of artificial feeding.
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Nygård, Torgeir, Karl-Otto Jacobsen i Jan Ove Gjershaug. "Home-range, movements and use of powerline poles of Eagle-Owls (Bubo bubo) at an island population in northern Norway". Ornis Fennica, 10.07.2023, 00. http://dx.doi.org/10.51812/of.116340.
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A dense island population of Eagle-Owls (Bubo bubo) close to the Arctic circle had suffered considerable mortality due to powerlines (electrocution and collision) throughout many decades. A study using GPS transmitter technology was carried out between 2009 and 2014. We studied home-range sizes, dispersal distances, mortality, and proposed mitigation techniques to prevent accidents. We found as expected that juvenile Eagle-Owls had larger home-ranges and moved farther than adults, but both age-groups moved much less than shown elsewhere in Europe. The probable reason for this was thought to be that this population was isolated by the surrounding sea, which might act as a barrier. The GPS data indicated that the poles of the grid were used as perching posts more than expected from a random distribution. This was explained by the lack of high trees and other elevated landscape features on these low islands. As a mitigation effort, we contributed to designing a perching-device for fitting on the poles that would prevent electrocution of the owls. This is now used by several grid-owners in coastal areas with high electrocution risk and is followed up by the National action plan for Eagle-Owl in Norway.
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Kortesalmi, Pihla, Salli Pääkkönen, Janne Valkonen i Ossi Nokelainen. "Bean goose migration shows a long-term temporal shift to earlier spring, but not to later autumn migration in Finland". Ornis Fennica, 12.04.2023, 00. http://dx.doi.org/10.51812/of.119806.
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Climate change can challenge the inherited or learned behavioural patterns that were useful in the past. In particular, it may change the spatio-temporal dynamics of migratory behaviour in birds. Here, we explored a 40-year-long time series of Bean Goose (Anser fabalis) observations using a citizen science database (tiira.fi – BirdLife Finland) to link the timing of the migration across last forty years and with the large-scale temporal weather fluctuation described by an index of North Atlantic Oscillation (NAO). During 1978–2018, the peak of spring migration of the Bean Goose has advanced approximately a month, whereas the timing of autumn migration has remained more similar across the years. The NAO index was associated only with spring migration. Strong temporal changes of the Bean Goose migration are evident as they adjust their migratory behaviour to changing spring conditions.
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Lõhmus, Asko. "The Mistle Thrush (Turdus viscivorus) in a production forestry context: A territory mapping study". Ornis Fennica, 20.02.2023, 00. http://dx.doi.org/10.51812/of.120604.
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In Northern Europe, the Mistle Thrush (Turdus viscivorus) is a relatively poorly studied species inhabiting forested landscapes where it has historically experienced population declines. Those declines have been attributed to the spread of intensive forest management; yet, the populations have stabilized or increased in recent decades. To distinguish the main forestry impacts on its breeding numbers and distribution, a multiple-visit territory-mapping study was carried out over 15 km2 of production forest landscape in Estonia. At the landscape scale, the breeding distribution was concentrated to conifer forests on bog peat where the densities were five times higher than in other conifer forests and (at least) ten times higher than in non-conifer forests. This reveals a broad distribution pattern where high-density (core) habitats only host a small fraction of the total population; their relative contribution to the recruitment remains unknown. At the breeding territory scale (within 150 m from a nest), Mistle Thrushes avoided recent clear-cuts and preferred larger areas of old stands more than expected from the distribution of suitable stands for nesting. This indicated that, in a short term, clear-cutting reduces nesting habitats of this species disproportionately more than expected from the cut area alone; this is in accordance with the documented 20th century declines of the species in Fennoscandia. The relationship with forestry drainage is more complicated, however, due to delayed effects and covariation with the main breeding habitat. The basic ecology of the species in conifer forest-wetland landscapes, which are subjected to management pressures, warrants future studies and might provide general insights into the dynamics and functioning of these ecosystems.
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Vassileva, Liliana V. "Are Grey Plovers true Jelly Bon lovers? First record of Grey Plovers (Pluvialis squatarola) deliberately feeding on barrel jellyfish (Rhizostoma pulmo) in the Western Palearctic". Ornis Fennica, 16.12.2023, 00. http://dx.doi.org/10.51812/of.121247.
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Coelenterates are not considered important food items for waders such as Grey Plovers (Pluvialis squatarola), although this has rarely been investigated in detail. During three days of fieldwork on the Bulgarian Black Sea coast in October 2020 Grey Plovers were documented deliberately choosing and swallowing barrel jellyfish Rhizostoma pulmo (Scyphozoa: Rhizostomatidae) while foraging on sand seashore where Scyphozoan jellyfish are often stranded. According to peer-reviewed literature, there is to-date no evidence of Grey Plovers consuming scyphozoan medusae, particularly as a specific choice for their food components. As a result of the present study, it is concluded that barrel jellyfish is part of the diet of Grey Plovers on the Black Sea coast and is purposely chosen by them. So far, this is the first video-recorded observation and published record of such an event in Europe and Western Palearctic. It suggests that coelenterates may be more important food items for waders than previousely believed and shows the potential of medusae to become an important food alternative for them.
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Zbyryt, Adam, Cezary Mitrus i Grzegorz Neubauer. "Productivity of the Great Egret (Ardea alba) and Grey Heron (A. cinerea) in mixed heronries in Poland and behavioral response of fledglings to a drone". Ornis Fennica, 22.01.2024, 00. http://dx.doi.org/10.51812/of.119429.
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Productivity of avian populations provides important demographic information helpful in understanding population dynamics and processes involved during species expansions. We tested the hypothesis that the productivity of the two species of ecologically similar herons that breed together in mixed heronries is related to their expansion status. We expected the expansive species, colonizing the new area and increasing in numbers, to outperform the native species, whose abundance is stable. We studied the breeding success of two herons in mixed colonies in eastern Poland in 2018: Great Egret (Ardea alba) (an expansive species, increasing breeding range and population size), and the Grey Heron (Ardea cinerea) (a native species, stable breeding population). Mean productivity (number of young per nest) was similar for Great Egret and Grey Heron and appeared correlated to each other in mixed heronries. Productivity of both species was unrelated to the colony size, but Grey Heron tended to have higher productivity as the proportion of Great Egret nests in the colony increased. Similar productivity of both species can be explained by the sufficient food resources coupled with the low level of competition. The two species differed significantly in their response of young to the approaching drone: the mean probability of a young Great Egret adopting an upright display was 0.47 compared to only 0.18 in a young Grey Heron (P=0.025). This was unlikely an age-related difference as the fledglings of both species were at a similar stage of development, but may represent some kind of a species-specific trait. Our research once again shows that UAVs allow a quick and non-invasive study of the size of the breeding populations and reproductive performance of herons, egrets and other wading birds.
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Boeyink, Clayton, i Simeon Koroma. "(De)coloniality of “Tethered Mobilities” in Freetown, Sierra Leone and Nyarugusu Refugee Camp, Tanzania". Migration and Society, 1.12.2023, 1–17. http://dx.doi.org/10.3167/arms7.010224.of.
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Drawing from historical case studies from Sierra Leone and Tanzania, this article fundamentally asks, what constitutes decoloniality? Before answering, we analyze the enduring coloniality of national borders, internal boundaries and identities, and manipulation and coercive imposition of (im)mobility. These colonial logics create “tethered mobilities” moving internal and external migrants in and out of approved spaces to facilitate extraction and racialized categorizations. We explore the impact of these aspects of coloniality on rural-urban migration and law in Sierra Leone and forced migration and containment of citizens and refugees in Tanzania. Conversing with critical migration and abolition literatures, we argue that despite no explicit revolutionary intent, migrants create their own tethered mobilities through everyday life-making in prohibited spaces as “rehearsal” for decolonial futures and mobility justice.
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Dubiec, Anna, i Tomasz Mazgajski. "Assessing timing of fledging in a cavity-nesting passerine using temperature data loggers". Ornis Fennica, 23.10.2023, 00. http://dx.doi.org/10.51812/of.126936.
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In altricial birds, the length of the nestling period, i.e. time from hatching until fledging (young leaving the nest) varies within and between species. In general, however, variation in the time of fledging and factors mediating such variation remain largely unexplored. To assess the time of nestlings leaving the nest, daily observer visits to the nest are usually done in the predicted fledging period. However, this might initiate premature fledging of young and/or increase the predation risk. The application of iButtons – coin-sized temperature data loggers, which are increasingly used in ornithological studies – may help to overcome these obstacles. We tested whether nest temperatures recorded with iButtons might be used to identify the date and hour of young fledging, i.e. when the last nestling in the brood left the nest, in a small cavity-nesting passerine – the Great Tit (Parus major). We installed iButtons in 38 nests when nestlings were 14–15 days old (hatching day = day 0) and verified the presence of nestlings during daily inspections starting on day 17 post-hatching or later. We found that the day of fledging could be accurately determined based on the difference between the temperature of the nest cup and the outside. The age of nestlings ranged between 17 and 22 days at fledging, with nearly 58% of broods fledging at the age of 20 and 21 days. The majority (81.6%) of broods fledged within 6 h after sunrise. We discuss the advantages and disadvantages of using iButtons to identify fledging time in altricial birds.
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Pakanen, Veli-Matti, i Reijo Kylmänen. "High adult survival in a northern Eurasian Curlew (Numenius arquata) population". Ornis Fennica, 23.10.2023, 00. http://dx.doi.org/10.51812/of.126810.
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Wetland birds such as waders are in decline across Europe. Information on demography is vital for assessing the causes of population declines, but estimates are needed from multiple populations and time periods. We used capture-recapture data from 2013–2022 including 134 individuals to estimate sex-specific apparent adult survival of Eurasian Curlews from a population breeding on agricultural fields in Finland, a stronghold region for this species in Europe. Using the Cormack–Jolly–Seber-model that considers the recapture probability of individuals, we estimated apparent survival of adults to be 0.89 (SE 0.03) for males and 0.92 (SE 0.03) for females. Our estimates of adult survival are slightly higher than those previously estimated from Fennoscandian breeding grounds in 1980s–1990s (0.82–0.88). Thus, our results suggest that adult survival of populations breeding in northern Europe has not declined during the last decades. Our study supports the view that changes in reproductive success is the main cause of decline in the Eurasian Curlew populations.
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Arizaga, J., i F. Bairlein. "The role of age, sex, subspecies, body size and fuel load in determining the social status of a migratory passerine during the non-breeding period". Ornis Fennica 88, nr 3 (30.09.2011). http://dx.doi.org/10.51812/of.133778.
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The social status is seen determined by sex and/or age, body size and body condition. However, knowing which of these factors play a more relevant role to determine social dominance is often difficult since studies of competition under field conditions are com-monly affected by several confounding factors that cannot be controlled or are even un-known. We studied experimentally which factors determine the dominance in captive Northern Wheatears, Oenanthe oenanthe during the non-breeding season, i.e., autumn and winter. We subjected two individuals at a time to experimental conditions with food provided at a feeder; these individuals differed in sex, age, body size, fuel load and sub-species. Social status appeared to be determined by age and sex during the autumn migra-tion period, but not in winter. In particular, adults and males displaced first-year birds and females from the feeding site. Other traits such as body size, fuel load and subspecies, did not have significant effects on the social status.
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Lu, X., Y. Guo, J. Liang, X. Markowski i L. Zhang. "Breeding ecology of the Twite Carduelis flavirostris in northern Tibet". Ornis Fennica 88, nr 3 (30.09.2011). http://dx.doi.org/10.51812/of.133780.
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The breeding ecology of the Twite was studied during 2004-2007 in a meadow environment at 4,300 m elevation, in northern Tibet. Twite laid eggs between late May and mid-August in response to ripeness of seed food. Nests were located in firewood stacks, trees and marshes, with average inter-nest distances less than 15 m. Pairs formed monogamously and males used both proximity and frequent copulations to guard their paternity. Clutch size averaged 4.2 (± 0.7 SD; 3-7), seasonally increasing or remaining unchanged according to year. Incubation by the female only lasted 12.2 days (± 1.2 SD; 10-15) and provisioning of chicks in the nest was continued by both parents for 14.7 days (±1.1 SD; 7 13-17). Males performed courtship feeding when their mates were engaged in egg-laying, incubating and brooding. Breeding success, measured as the percentage of nesting attempts from which at least one nestling fledged, was 64%. Compared to their lowland counterparts, Tibetan Twite produced smaller clutches and larger eggs, suggesting a life history strategy to cope with the harsh high-elevation environment.
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Østnes, Jan E., Rolf T. Kroglund, Oddmund Kleven i Torgeir Nygård. "Migratory patterns of Ospreys (Pandion haliaetus) from central Norway". Ornis Fennica 96, nr 3 (30.09.2019). http://dx.doi.org/10.51812/of.133952.
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Migratory behaviour is subject to intraspecific variation and may be determined by the age, sex and population origin of individuals. Here we equipped eight juvenile Ospreys (Pandion haliaetus) with GPS-based satellite-transmitters to investigate their migratory behaviour from a recently re-established breeding area in central Norway. Migration routes fanned out widely across Europe, and migratory behaviour differed between individuals. Five of the eight Ospreys completed their first southward migration to wintering areas in tropical Africa. They travelled a median distance of 7,482 km and spent from 21 to 92 days on their journeys. Median travel distance was 120% longer than a straight-line distance. Stopover sites were located just before or immediately after crossings of geographical barriers and the differences in the time spent on the migratory journeys was mainly a consequence of the number of stopover days.
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Lehikoinen, Aleksi, Jarkko Santaharju i Anders M. "Sex-specific timing of autumn migration in birds: the role of sexual size dimorphism, migration distance and differences in breeding investment". Ornis Fennica 94, nr 2 (1.07.2017). http://dx.doi.org/10.51812/of.133912.
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Multiple studies have investigated differential migration of sexes during spring migration, while such differences during autumn migration are poorly studied.We tested several functional hypotheses explaining differences in autumnmigration dates between sex and age classes and whether these patterns vary between short- and long-distance migrants (SDMs andLDMs, respectively).We used data of ringed birds from the Hanko and Lågskär Bird Observatory, Finland, North Europe. Altogether data for c. 200,000 ringed birds including 14 passerine species were used. Protogyny,with femalesmigrating earlier than males, was common among young birds, and this difference was clearer in LDMs than inSDMs.However, in adults protogyny was not found, whereas protandy,malesmigrating earlier than females,was found in two species. Furthermore, species-specific sexual size dimorphism, SSD, was significantly connected with the time differences in migration between the sexes in SDMs, but not in LDMs. These results suggest thatmultiple factors are likely affecting differential timing of autumnmigration in birds. It can be beneficial for males, especially young birds, to spend additional time at the breeding grounds to prospect for future nesting sites. The connection between SSD and autumn migration dates in SDM could be linked with the pattern where larger sized individuals can winter closer to the breeding grounds. In addition, later migration dates of adult females compared to adultmales could suggest that larger reproductive investment by adult females on breeding may delay their autumn migration.
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Zaniewicz, Grzegorz, Wlodzimierz Meissner i Agnieszka Ozarowska. "Estimation of fat reserves of Robins (Erithacus rubecula) migrating through the southern coast of the Baltic Sea in spring". Ornis Fennica 95, nr 1 (31.03.2018). http://dx.doi.org/10.51812/of.133928.
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Fat is the main source of energy during bird migration, and the visual fat scoring is widely used in the studies on, e.g., stopover ecology of migratory species. Yet, visual fat scoring can lead to wrong conclusion due to potentially different pattern of fat distribution in species that differ in size or even individuals being during active migration and those at stopovers. To overcome limitations of this method, we developed the predictive equation for estimating fat reserves in spring-migrating Robins – one of the most numerous migratory species in Europe. The equation allows estimating the amount of fat reserves based on body mass of birds, which was the best predictor of fat mass accumulated by Robins. The predictive value of the equation was reasonable with the coefficient of determination equal to 0.56 and the standard error of estimation SEE = 0.36. This equation was tested on the sample of adult and immature Robins captured during spring migration. The studied species is a typical short/medium distance migrant employing short step migration, which does not require large fat reserves.
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Konovalov, Annika, Rein Nellis, Renno Nellis, Ain Nurmla, Urmas Sellis i Ülo Väli. "Solitude at periphery: lack of partners limits reproduction of the Black Stork (Ciconia nigra) at the margin of the distribution range". Ornis Fennica 96, nr 1 (31.03.2019). http://dx.doi.org/10.51812/of.133943.
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Understanding the mechanisms forming species’ ranges is a central ecological question, which could be answered by analysing factors limiting peripheral populations. In threatened species, such studies are essential for establishing effective conservation measures across the range. We analysed factors potentially influencing breeding in a declining peripheral population of a long-lived bird, the Black Stork (Ciconia nigra). We assessed reproductive success and the effects of intra- and interspecific competition, as well as predation by recording events at nests by remote cameras (camera traps and a webcam). Productivity of storks was low (1.1 fledglings per occupied nest) compared to the other parts of the range and resulted mainly from the lower proportion of successful nests (37% of occupied nests). The main reason for low breeding success was the occupancy of many nests (35%) by single non-reproductive birds.
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Andersson, Noora, Markus Piha, Kalle Meller, Kaisa Välimäki i Aleksi Lehikoinen. "Variation in body condition of songbirds during breeding season in relation to sex, migration strategy and weather". Ornis Fennica 95, nr 2 (1.07.2018). http://dx.doi.org/10.51812/of.133931.
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Animal body reserves are often linked with demographic parameters such as breeding success and survival. During breeding season individuals face a trade-off between maintaining body reserves and investing in reproduction. Factors influencing the body reserves of species during breeding season are poorly understood. In this study, we used long-term trapping data from Finnish Constant Effort Sites program to evaluate the impact of sex, migration behaviour, and weather on body reserve index (BRI) of old and young birds during breeding season in 20 species. Our main interest was to study how variation in weather conditions influences the BRI of breeding passerine birds. Weather variables did not explain BRI of adults. However, we found that BRI of young birds was weakly negatively connected with mean temperature, but this may have low biological importance. BRI of adult males increased towards the end of August, but female BRI showed a seasonal decline throughout June and July.
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Sevcík, Richard, Jan Riegert, Jirí Sindelár i Marketa Zarybnicka. "Vocal activity of the Central European Boreal Owl population in relation to varying environmental conditions". Ornis Fennica 96, nr 1 (31.03.2019). http://dx.doi.org/10.51812/of.133942.
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Vocal activity is one of the main attributes that enables assessment of the presence and abundance of animal populations. However, the factors affecting vocal activity are rarely studied, especially in owls. We studied the vocal activity of Boreal Owl (Aegolius funereus) using acoustic monitoring in relation to environmental factors in Central Europe (Czech Republic), over an area of 100 km2. We analysed a total of 1,310 hours of sound recordings collected over two years (2015 and 2016) at the turn of March/April and April/May. The frequency of sampling points in which we recorded Boreal Owl vocalizations varied from 0.17 to 0.59 and was higher in the year of increased prey abundance (2015) and earlier in the breeding season (March/April). The duration of Boreal Owl vocal activity varied from 1 to 60 minutes per hour and was related to temporal factors. In particular, the duration of Boreal Owl vocalization increased late in the breeding season (April/May) and in the year of higher prey abundance (2015), and it showed two peaks of vocal activity during the night.
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Tobolka, Marcin, Tim H. Sparks i Piotr Tryjanowski. "Does the White Stork Ciconia ciconia reflect farmland bird diversity?" Ornis Fennica 89, nr 3 (30.09.2012). http://dx.doi.org/10.51812/of.133809.
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The White Stork (Ciconia ciconia) is an icon of nature protection and one of the easiest birds to monitor, particularly in Central Europe. Here avian biodiversity was compared between sites (territories) occupied by nesting White Storks and sites that were formerly occupied but were unoccupied during the two study years, and often for several preceding years. The study was conducted in Western Poland during two breeding seasons, 2007 and 2008, involving 43 and 54 territories, respectively. Moreover, information on nest oc-cupancy and breeding success of White Storks since 2005 was used as a measure of habi-tat quality. Breeding bird diversity was significantly higher in occupied than in unoccu-pied White Stork territories. Bird diversity was also higher in territories with better White Stork chick productivity in the period 20052008. Even greater differentiation in bird di-versity might have been achieved between occupied White Stork territories and random sampling points in similar habitat.
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Peiró, Ignacio G., i Emilio Pagani-Núñez. "Plumage colouration variability of male Bluethroats (Luscinia svecica cyanecula) wintering in SE Iberia". Ornis Fennica 93, nr 2 (1.07.2016). http://dx.doi.org/10.51812/of.133893.
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Male colouration has a key role in signalling individual quality during the breeding season. Although winter plumage probably correlates with summer plumage, few studies have focused on the determinants of male colouration during the non-breeding period. If plumage colouration is related to an individual’s age or is strongly correlated with body condition during the non-breeding period, this trait could be used by conspecifics to assess quality, origin or status of a given individual.Here,we analysed plumage colouration and body size of male Bluethroats (Luscinia svecica cyanecula) wintering in SE Iberia. We found that young individuals had narrower black bands and wider white bands than adult individuals in their throat patch.Also, thewidth of the chestnut band increased with later capture date. Finally, blue throat colouration was positively correlated with tail length and negatively correlatedwith tarsus length.We could not find any significant relationship between throat patch colouration and bodymass.We concluded that individual’s age and capture date were significantly related to black and chestnut throat colouration, respectively. Therefore, these coloured bands could provide reliable cues on individual’s age and their geographical origins. The variability of plumage colouration of wintering Bluethroats provides an excellent study system in which to test further hypotheses on the role of the throat patch colouration outside the breeding season.
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Golawski, A., i Z. Kasprzykowski. "The influence of weather on birds wintering in the farmlands of eastern Poland". Ornis Fennica 87, nr 4 (31.12.2010). http://dx.doi.org/10.51812/of.133754.
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Counts of wintering birds were conducted in the extensively cultivated farmland of eastern Poland during three seasons. The number of wintering species of birds was negatively correlated with the depth of snow and positively related to the number of species recorded during the previous count. The total number of birds was negatively correlated with the depth of snow cover and positively correlated with the total number of birds recorded during the previous count. To a great extent it was the presence of snow cover that shaped the assemblages of birds wintering in farmland. During long-lasting snow, birds may leave this type of landscape. At wintering grounds influenced by conditions similar to those in eastern Poland the depth of snow may be of greater importance for birds than the presence of suitable feeding habitats because food is limited. As a consequence of the global climate change, changes in snow cover will occur and should increase the numbers and abundance of bird species wintering in eastern Poland.
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Rosenberger, Joanna, Ewa Lukaszewicz, Artur Kowalczyk, Denis Deeming i Zenon Rzonca. "Nesting behaviour of Capercaillie (Tetrao urogallus) females kept in aviaries". Ornis Fennica 93, nr 3 (30.09.2016). http://dx.doi.org/10.51812/of.133896.
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For many bird species in captivity the best practice for incubation procedures have not been yet developed. This is hampered by a lack of cooperation between bird breeders or by a reluctance to experiment on valuable eggs. The last two problems may be solved by observation of natural incubation, which technology has made a lot easier. Many studies document incubation behavior: daily time spend in the nest, preferred hours of making abscences, egg turning rate and incubation temperature. Such data is scientifically interesting but also allows for better protection of endangered species through development of captive breeding programmes. The Capercaillie (Tetrao urogallus) is a threatened species over much of its European range and various conservation actions are being taken to save populations from global or local extinction. Our study took place in Capercaillie Breeding Centre in Wisla Forestry District and describes nesting and incubation behaviour of Capercaillie females kept in captivity. Our aim was to better document the nesting behaviour by recording egg turning rate, and the time and length of incubation recesses. Time of and day of incubation had no significant influence on recess length, but the number of recesses was related with time of day with two peaks at 06:00h and 18:00h . Egg turning activity was the greates during the first and last two days of incubation but generally consistent throughout the rest of incubation. Captive hens spent less time outside of the nest than wild ones, their absences were shorter, rarer and took place mostly in the evening. However, differences in the preferred absence hours were not as clearly markes as in the case of wild birds. We hope that this information will help improve management practises to maximise the reproductive output of captive Capercaillie.
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Boström, Maria K., Sven-Gunnar Lunneryd, Hanna Ståhlberg, Lars Karlsson i Bjarne Ragnarsson. "Diet of the Great Cormorant (Phalacrocorax carbo sinensis) at two areas in the Bay L vstabukten, South Bothnian Sea, Sweden, based on otolith size-correction factors". Ornis Fennica 89, nr 3 (30.09.2012). http://dx.doi.org/10.51812/of.133803.
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The diet of cormorants roosting at Malause on the Garonne River (South- West France) was studied by analyzing pellets collected during the winter 2001- 2002. This roost held a mean of 550 cormorants between October 2001 and March 2002, making it one of the most important winter roosts in France. The diet contained 14 fish species, including 10 cyprinids. Cyprinids were the most abundant prey, representing 90 % of individual fish. Bream Abramis brama between 100 and 150 mm in length were the most abundant food items, while large bream ( >300mm total length) were also consumed. The proportion of pellets containing bream increased from 26 % in October- November to 69% in February- March. There was no significant change in the size of the bream over time. The next most abundant species was pikeperch Sander lucioperca present in 15.4% of the pellets from December- January but only 2.6% in February- March.