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1
Galloway, Terry D., et Robert J. Lamb. « Population Dynamics of Chewing Lice (Phthiraptera) Infesting Birds (Aves) ». Annual Review of Entomology 66, no 1 (7 janvier 2021) : 209–24. http://dx.doi.org/10.1146/annurev-ento-041420-075608.
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In the past 25 years, studies on interactions between chewing lice and their bird hosts have increased notably. This body of work reveals that sampling of live avian hosts, collection of the lice, and the aggregated distributions of louse infestations pose challenges for assessing louse populations. The number of lice on a bird varies among host taxa, often with host size and social system. Host preening behavior limits louse abundance, depending on bill shape. The small communities of lice (typically one–four species) that live on individual birds show species-specific patterns of abundance, with consistently common and rare species, and lower year-to-year population variability than other groups of insects. Most species of lice appear to breed continuously on their hosts, with seasonal patterns of abundance sometimes related to host reproduction and molting. Competition may have led to spatial partitioning of the host by louse species, but seldom contributes to current patterns of abundance.
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Galloway, Terry D., et Robert J. Lamb. « Population Dynamics of Chewing Lice (Phthiraptera) Infesting Birds (Aves) ». Annual Review of Entomology 66, no 1 (7 janvier 2021) : 209–24. http://dx.doi.org/10.1146/annurev-ento-041420-075608.
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In the past 25 years, studies on interactions between chewing lice and their bird hosts have increased notably. This body of work reveals that sampling of live avian hosts, collection of the lice, and the aggregated distributions of louse infestations pose challenges for assessing louse populations. The number of lice on a bird varies among host taxa, often with host size and social system. Host preening behavior limits louse abundance, depending on bill shape. The small communities of lice (typically one–four species) that live on individual birds show species-specific patterns of abundance, with consistently common and rare species, and lower year-to-year population variability than other groups of insects. Most species of lice appear to breed continuously on their hosts, with seasonal patterns of abundance sometimes related to host reproduction and molting. Competition may have led to spatial partitioning of the host by louse species, but seldom contributes to current patterns of abundance.
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Virkkala, Raimo, et Ari Rajasärkkä. « Climate change affects populations of northern birds in boreal protected areas ». Biology Letters 7, no 3 (8 décembre 2010) : 395–98. http://dx.doi.org/10.1098/rsbl.2010.1052.
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Human land-use effects on species populations are minimized in protected areas and population changes can thus be more directly linked with changes in climate. In this study, bird population changes in 96 protected areas in Finland were compared using quantitative bird census data, between two time slices, 1981–1999 and 2000–2009, with the mean time span being 14 years. Bird species were categorized by distribution pattern and migratory strategy. Our results showed that northern bird species had declined by 21 per cent and southern species increased by 29 per cent in boreal protected areas during the study period, alongside a clear rise (0.7–0.8°C) in mean temperatures. Distribution pattern was the main factor, with migratory strategy interacting in explaining population changes in boreal birds. Migration strategy interacted with distribution pattern so that, among northern birds, densities of both migratory and resident species declined, whereas among southern birds they both increased. The observed decline of northern species and increase in southern species are in line with the predictions of range shifts of these species groups under a warming climate, and suggest that the population dynamics of birds are already changing in natural boreal habitats in association with changing climate.
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Matsyura, О. V. « КОМПЛЕКСНА ОЦІНКА ДИНАМІКИ ЧИСЕЛЬНОСТІ УГРУПОВАНЬ КОЛОНІАЛЬНИХ НАВКОЛОВОДНИХ ПТАХІВ (НА ПРИКЛАДІ ДЕЯКИХ ОСТРОВІВ СИВАШУ) ». Biological Bulletin of Bogdan Chmelnitskiy Melitopol State Pedagogical University 1, no 3 (25 décembre 2011) : 85. http://dx.doi.org/10.15421/20111_38.
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<p>The problem of the mathematical analysis of the number dynamics of the nesting waterbirds for the islands of the south of Ukraine is examined. The algorithm of the evaluation of changes in the number of island birds is proposed. Data of the long-term monitoring of the number of birds were analyzed according to this algorithm. The necessity of the implementation of the statistical indices together with the graphic representation of island birds’ turnover is proved. The trends of population dynamics are determined for the key species. The discussed procedure of the complex evaluation is proposed for the management planning of the island bird species and their habitats.</p> <p>The performed analysis of the number dynamics of the key-stone breeding island birds showed that, with the exception of little tern, the population status and the prognosis of number are sufficiently favorable. From the data of long-term monitoring we came up with the conclusion about the existence of island habitats with carrying capacity to maintain the additional number of breeding birds. In the case of unfavorable conditions like strengthening of anthropogenic press, concurrent interrelations, deficiency of feed resources or drastic reduction of breeding biotopes, the birds due to turnover are capable to successfully react even without reducing their number and breeding success. The extinction rate of the breeding bird species from the island sites directly correlates with the number of breeding species. For the species with equal abundance, the extinction probability is higher for birds, whose numbers are unstable and characterized by significant fluctuations. This testifies the urgency of the constant monitoring and analysis of the number dynamics of breeding bird species in region.</p> <p>The suggested procedure of analysis is recommended for drawing up of management plans and performing of prognoses of number of breeding island bird species. More detail analysis with use of quantitative data on breeding birds will be the next step of the study of the island birds’ turnover. The results of the analysis of population dynamics assist to count the minimal population size for the colonization of new islands and stable existence of bird communities. Detailed analysis will allow to estimate the effect of competition on population and to determine the competitive variability inside and between the species breeding on islands.</p> <p><em>Key words: Ukraine, colonial waterbirds, islands, dynamics of number, analysis</em></p> <p> </p>
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JHA, Kaushalendra Kumar, et Craig R. MCKINLEY. « Composition and Dynamics of Migratory and Resident Avian Population in Wintering Wetlands from Northern India ». Notulae Scientia Biologicae 7, no 1 (20 mars 2015) : 1–15. http://dx.doi.org/10.15835/nsb719484.
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Twelve wetlands occurring in four different ecozones in Uttar Pradesh (UP), India, were selected for studying the winter composition and dynamics of avian populations. Wetland information was collected from office records of the UP Forest department. Bird populations were estimated by transect method and block-in-flock-in-sector method for woodland and aquatic birds, respectively. Across the twelve selected wetlands a total of 486,182 individuals belonging to 161 species of birds on 15,592 ha were recorded during the winter of 2010-11. The data were analyzed to assess the relationship between wetland characteristics and avian populations. Aquatic vegetation, surrounding vegetation, water availability and climate were found as important factors related to avian populations. January was found to be the peak of bird assemblage, while winter times before and after January were the waxing and waning period, respectively. Species richness and species diversity of aquatic birds varied between 18-58 and 1.90-3.20, respectively, and of all bird species between 23-109, and 1.73-3.81, respectively. The density of aquatic birds ranged between 17-384 ha-1. The most common migratory birds in wetlands were Northern Pintail, Common Teal and Greylag Goose. Common resident birds included Asian Openbill, Darter, Little Egret, Common Coot, Little Cormorant, Grey Heron, Purple Heron, Indian Pond Heron, Common Moorhen, Purple Swamphen, Cattle Egret, Indian Sarus Crane and White-throated Kingfisher. For improved conservation of aquatic avian fauna, management prescriptions are suggested for wetlands under current management which could also be extended to other wetlands, whereas conservation of avian fauna to be the emphasis.
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Sakhvon, V. V., et M. E. Nikiforov. « Features of formation bird population structure in Minsk in the time aspect ». Proceedings of the National Academy of Sciences of Belarus, Biological Series 66, no 4 (10 novembre 2021) : 412–25. http://dx.doi.org/10.29235/1029-8940-2021-66-4-412-425.
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The structure of bird population of urbanized areas is determined by the diversity of habitats within the city, the diversity of bird species in suburban biotopes, and regional processes of dispersal of birds closely associated with human settlements. The analysis of the dynamics of the breeding bird species richness in Minsk showed that its formation progressed in different ways. All in all, since 1946, 141 bird species have been recorded nesting (including allegedly) in the territory of Minsk.The breeding bird assemblages is dominated by dendrophilous (45.0 % of all species) as well as wetland and semi-aquatic (29,3 %) bird species, with more than half of all the breeding bird species (50.3 %) associated with trees and shrubs. In different periods, the breeding bird species richness varied, by now, it has noticeably increased (from 77 to 132 species). This happened due to the expansion of the administrative boundaries of the city with the inclusion of bird species of suburban habitats, an increase in the diversity of habitats suitable for bird nesting (for example, the formation of large water bodies) as well as due to active colonization of urban ecosystems by various bird species. At the same time, after 2000, 9 bird species stopped nesting and 17 bird species started nesting. Active processes of synurbization of some bird species on the European continent observed in recent decades have become the reason for the addition of new species to the avifauna in Minsk, although the basis of the current structure of bird population was formed back in 1986–1999. At the same time, the synurbized groups of various bird species may be of autochthonous, allochthonous, or mixed origin.
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Odintseva, A. A., et O. A. Odintsev. « Seasonal Dynamics of the Bird Population of Omsk City ». Biology Bulletin 48, no 7 (décembre 2021) : 1030–40. http://dx.doi.org/10.1134/s1062359021070220.
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Sæther, Bernt-Erik, Russell Lande, Steinar Engen, Henri Weimerskirch, Magnar Lillegård, Res Altwegg, Peter H. Becker et al. « Generation time and temporal scaling of bird population dynamics ». Nature 436, no 7047 (juillet 2005) : 99–102. http://dx.doi.org/10.1038/nature03666.
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Ruffino, Lise, Diane Zarzoso-Lacoste et Eric Vidal. « Assessment of invasive rodent impacts on island avifauna : methods, limitations and the way forward ». Wildlife Research 42, no 2 (2015) : 185. http://dx.doi.org/10.1071/wr15047.
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Bird conservation is nowadays a strong driving force for prioritising rodent eradications, but robust quantitative estimates of impacts are needed to ensure cost-effectiveness of management operations. Here, we review the published literature to investigate on what methodological basis rodent effects on island bird communities have been evaluated for the past six decades. We then discuss the advantages and limitations of each category of methods for the detection and quantification of impacts, and end with some recommendations on how to strengthen current approaches and extend our knowledge on the mechanisms of impacts. Impact studies (152 studies considered) emphasised seabirds (67%), black rats (63%) and the Pacific Ocean (57%). Among the most commonly used methods to study rodent impacts on birds were the observation of dead eggs or empty nests while monitoring bird breeding success, and the analyses of rodent diets, which can both lead to misleading conclusions if the data are not supported by direct field evidence of rodent predation. Direct observations of rodent–bird interactions (19% of studies) are still poorly considered despite their potential to reveal cryptic behaviours and shed light on the mechanisms of impacts. Rodent effects on birds were most often measured as a change or difference in bird breeding parameters (74% of studies), while estimates of bird population growth rates (4%) are lacking. Based on the outcomes of this literature review, we highlight the need for collecting unbiased population-level estimates of rodent impacts, which are essential prerequisites for predicting bird population growth scenarios and prioritising their conservation needs. This could be achieved by a more systematic integration of long-term monitoring of bird populations into rodent management operations and modelling bird population dynamics. We also strongly recommend including various complementary methods in impact assessment strategies to unravel complex interactions between rodents and birds and avoid faulty evidence. Finally, more research should be devoted to a better understanding of the cases of non-impacts (i.e. long-term coexistence) and those impacts mediated by mechanisms other than predation and ecosystem-level processes.
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Layton-Matthews, Kate, Michael Griesser, Christophe F. D. Coste et Arpat Ozgul. « Forest management affects seasonal source-sink dynamics in a territorial, group-living bird ». Oecologia 196, no 2 (juin 2021) : 399–412. http://dx.doi.org/10.1007/s00442-021-04935-6.
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AbstractThe persistence of wildlife populations is under threat as a consequence of human activities, which are degrading natural ecosystems. Commercial forestry is the greatest threat to biodiversity in boreal forests. Forestry practices have degraded most available habitat, threatening the persistence of natural populations. Understanding population responses is, therefore, critical for their conservation. Population viability analyses are effective tools to predict population persistence under forestry management. However, quantifying the mechanisms driving population responses is complex as population dynamics vary temporally and spatially. Metapopulation dynamics are governed by local dynamics and spatial factors, potentially mediating the impacts of forestry e.g., through dispersal. Here, we performed a seasonal, spatially explicit population viability analysis, using long-term data from a group-living territorial bird (Siberian jay, Perisoreus infaustus). We quantified the effects of forest management on metapopulation dynamics, via forest type-specific demography and spatially explicit dispersal, and how forestry impacted the stability of metapopulation dynamics. Forestry reduced metapopulation growth and stability, through negative effects on reproduction and survival. Territories in higher quality natural forest contributed more to metapopulation dynamics than managed forests, largely through demographic processes rather than dispersal. Metapopulation dynamics in managed forest were also less resilient to disturbances and consequently, may be more vulnerable to environmental change. Seasonal differences in source-sink dynamics observed in managed forest, but not natural forests, were caused by associated seasonal differences in dispersal. As shown here, capturing seasonal source-sink dynamics allows us to predict population persistence under human disturbance and to provide targeted conservation recommendations.
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Robb, Gillian N., Robbie A. McDonald, Dan E. Chamberlain, S. James Reynolds, Timothy J. E. Harrison et Stuart Bearhop. « Winter feeding of birds increases productivity in the subsequent breeding season ». Biology Letters 4, no 2 (5 février 2008) : 220–23. http://dx.doi.org/10.1098/rsbl.2007.0622.
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Supplementary food given to birds can have contemporary effects by reducing the risk of starvation, increasing survival and altering movements and reproductive performance. There is, however, a widely held perception that birds benefit from extra food over winter, but that it is better that they ‘look after themselves’ during breeding. Here we describe a landscape-scale experiment showing for the first time that the effects of increasing food availability only during the winter can be carried over to the subsequent breeding season. Even though food supplementation stopped six weeks prior to breeding, birds living on sites provisioned over winter had advanced laying dates and increased fledging success compared with birds living on unprovisioned sites. Thus, supplemental feeding of wild birds during winter, in a manner mimicking householders provisioning in gardens and backyards, has the potential to alter bird population dynamics by altering future reproductive performance. With levels of bird feeding by the public continuing to increase, the impacts of this additional food supply on wild bird populations may be considerable.
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Rąkowski, Grzegorz, Krzysztof Czarnocki et Joanna Ukalska. « Breeding avifauna of mature forest stands in the Borki Forest and its dynamics at the turn of the 21st century ». Forest Research Papers 77, no 3 (1 septembre 2016) : 239–55. http://dx.doi.org/10.1515/frp-2016-0026.
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Abstract The composition and structure of the breeding bird community in the Borki Forest in north-eastern Poland were investigated during two separate periods: 1994–1996 and 2012–2014. Bird censuses were carried out in three plots located in mature oak-hornbeam, ash-alder and mixed coniferous forest stands. A standard combined mapping technique for estimating the number of breeding birds was applied. A total of 74 bird species bred at least once within any plot during 1994–1996 or 2012–2014. The structure of the bird assemblages on particular plots displayed a high degree of similarity, exceeding 75%, which means that they represent essentially the same bird community. However, the investigated assemblages have changed substantially over the 20 years. Both, the number of breeding bird species and the population densities on all plots, were much higher in 2012–2014 than in 1994–1996. The mean number of breeding species on all plots was over 50% higher in 2012–2014 than in 1994–1996, whereas the mean total density of breeding pairs increased by more than 60%. Total population densities on the plots increased as a result of an increase in population densities of individual bird species combined with an increase in the number of breeding species. Due to different rates of population growth for certain species, also the composition of dominating species group have changed. The observed changes in the avifauna of the Borki Forest were most probably due to an enrichment of the forest habitats structure, which was caused by natural factors, such as ageing of forest stands, forest succession and a change in water regime by beaver dams, as well as by forest management, including group felling within or in the vicinity of plots and uncovering of the forest edge.
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Ananin, A. A., et I. A. Aiurzanaeva. « Dependence of floodplain birds’ dynamics on the spring flood height and duration in the middle Ob River ». IOP Conference Series : Earth and Environmental Science 908, no 1 (1 novembre 2021) : 012012. http://dx.doi.org/10.1088/1755-1315/908/1/012012.
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Abstract Inter-annual variations in the total number of birds in floodplains of rivers are mainly associated with their flooding. The minimum population density during the nesting period was in a year with high and prolonged spring floods. The restoration and maximum development of shrubs took place with a significant simultaneous increase in the abundance of birds in subsequent years. Drying and simplification of vegetation cover were noted in all floodplain bird habitats during low-water periods. This process was accompanied by a decline in the number of birds. We identified four groups of bird species according to the criterion of the relationship “abundance – level and duration of the flood”. In the first group of bird species, abundance increased during high floods (3 species). In the second group, the abundance decreased sharply during high and prolonged floods (7 species). In the third group, the level and duration of the spring flood did not affect the abundance (9 species). In the fourth group, a very weak tendency of the negative flood level impact on the abundance of birds was noted (6 species).
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Sorokina, Julia Alexandrovna, et Elena Evgenievna Boryakova. « Recovery of the bird population within pine forests after the catastrophic fires in 2010 ». Samara Journal of Science 6, no 4 (1 décembre 2017) : 66–71. http://dx.doi.org/10.17816/snv201764113.
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Process of bird population restoration after fires was investigated in two protected areas in the Volga river basin in central Russia. Anthropogenic pressure in Kerzhensky and Mordovsky nature reserves is very low, it made possible to discover some characteristics of the process of bird population restoration in reference environment. The counts were carried out both in the affected areas of the reserves, and in unaffected parts. The studied area was in its five year after the fire. Dynamics of post fire bird population restoration and its dependence on both the age and history of the original ecosystems were investigated. The authors present the results of dominant species analysis and information about their distribution in the investigated natural reserves. The authors show peculiarities and proportions of ecological groups of birds in the studied territories as well as their proportion. The influence of hydrological parameters on bird communities composition was investigated, it turned out that post fire partial inundation leads to increase of waders of Gallinago and Tringa genera. Species diversity of bird communities in affected areas was considered. Using Pielous index it was found that species evenness remained relatively high, i.e. no significant increase of dominance was observed after the fires. The authors analyzed the composition of ornitocomplexes in terms of different faunistic groups.
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Mel’nikov, Yu I. « Modern climate warming, dynamics and development of new plots of bird areas as population adaptation to anthropogenic landscapes of Eastern Siberia ». IOP Conference Series : Earth and Environmental Science 1010, no 1 (1 avril 2022) : 012136. http://dx.doi.org/10.1088/1755-1315/1010/1/012136.
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Abstract The article discusses the features of the formation of new plots of the areas for birds in the anthropogenic landscapes of Eastern Siberia under the conditions of modern climate warming. It is emphasized that at the initial stages of this process, the warming was not intense and hardly noticeable (the beginning of the 19th - the first half of the 20th centuries). However, already at that time there was a clear trend towards the expansion of bird areas to the north and east. This process has progressed as the trend towards climate warming intensifies. In the second half of the 20th century, some typically western bird species reached Eastern Siberia. At the same time, extensive and prolonged droughts in the east of Central Asia caused a strong counter flow of dispersing birds to the west and north. In a number of bird species, mixing of the streams of dispersing birds was observed, and often these were closely related species. This indicates the formation of gaps in their once common areas that arose during periods of sharp cooling in previous climatic epoch. In the middle of the 20th century, the anthropogenic development of Eastern Siberia was very high. This facilitated the movement of birds of open landscapes far north. This fact is also emphasized by the oncoming flows of birds settling to the east and west as a result of severe and prolonged droughts in Central Asia. The birds of these streams crossed the Baikal rift zone (the northeastern zoogeographic boundary) and went far to the north - to the Central Yakut lowland and the tundra zone. The data obtained show that the development of new territories by birds and the expansion of their areas is associated with intense climate warming. The development of the territory by man only contributed to the movement of birds to new regions, due to the formation of more suitable habitats for birds (open and mosaic landscapes). Consequently, the intensification of climate warming, coinciding with the expansion of bird areas to the north, indicates that it was warming, and not intensive development of the territory by humans, that played the leading role in this process. The entire process currently observed is the adaptation of birds to the dynamic conditions of the new climatic period.
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Vögeli, Matthias, Paola Laiolo, David Serrano et José L. Tella. « Predation of experimental nests is linked to local population dynamics in a fragmented bird population ». Biology Letters 7, no 6 (14 avril 2011) : 954–57. http://dx.doi.org/10.1098/rsbl.2011.0241.
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Artificial nest experiments (ANEs) are widely used to obtain proxies of natural nest predation for testing a variety of hypotheses, from those dealing with variation in life-history strategies to those assessing the effects of habitat fragmentation on the persistence of bird populations. However, their applicability to real-world scenarios has been criticized owing to the many potential biases in comparing predation rates of artificial and natural nests. Here, we aimed to test the validity of estimates of ANEs using a novel approach. We related predation rates on artificial nests to population viability analyses in a songbird metapopulation as a way of predicting the real impact of predation events on the local populations studied. Predation intensity on artificial nests was negatively related to the species' annual population growth rate in small local populations, whereas the viability of large local populations did not seem to be influenced, even by high nest predation rates. The potential of extrapolation from ANEs to real-world scenarios is discussed, as these results suggest that artificial nest predation estimates may predict demographic processes in small structured populations.
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Sebaio, Fabiane, Érika Martins Braga, Felipe Branquinho, Alan Fecchio et Miguel Ângelo Marini. « Blood parasites in passerine birds from the Brazilian Atlantic Forest ». Revista Brasileira de Parasitologia Veterinária 21, no 1 (mars 2012) : 7–15. http://dx.doi.org/10.1590/s1984-29612012000100003.
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Parasites may lead bird species to extinction, affect host temporal and spatial population dynamics, alter community structure and alter individuals’ social status. We evaluated blood parasite prevalence and intensity according to bird families and species, among 925 birds that were caught in 2000 and 2001, in the Atlantic Forest in the State of Minas Gerais, Brazil. We applied Giemsa staining to thin blood smears, to detect blood parasites. The birds (n = 15.8%) in 11 families, were infected by at least one parasite genus, especially Muscicapidae (28.3%) and Conopophagidae (25%). Among the 146 infected birds, Plasmodium was detected in all bird families and had the highest prevalence (54.8%). Trypanosoma, Haemoproteus and microfilaria had lower prevalence rates (23.3, 23.3 and 2.1%, respectively). Birds caught during the rainy season were more infected than birds caught during the dry season. The overall low prevalence of blood parasites in birds is similar to the patterns found elsewhere in the Neotropical region.
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Rushing, Clark S., Thomas B. Ryder et Peter P. Marra. « Quantifying drivers of population dynamics for a migratory bird throughout the annual cycle ». Proceedings of the Royal Society B : Biological Sciences 283, no 1823 (27 janvier 2016) : 20152846. http://dx.doi.org/10.1098/rspb.2015.2846.
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Worldwide, migratory species are undergoing rapid declines but understanding the factors driving these declines is hindered by missing information about migratory connectivity and the lack of data to quantify environmental processes across the annual cycle. Here, we combined range-wide information about migratory connectivity with global remote-sensing data to quantify the relative importance of breeding and non-breeding environmental processes to persistent long-term population declines of a migratory songbird, the wood thrush ( Hylocichla mustelina ). Consistent with theoretical predictions about population limitation of migratory birds, our results suggest that habitat loss and climate have contributed to the observed declines in wood thrush breeding abundance, yet the relative importance of breeding versus non-breeding factors is population-specific. For example, high-abundance core breeding populations appear to be more limited by habitat loss, whereas low-abundance, peripheral populations appear to be limited by climate-driven seasonal interactions. Further, our analysis indicates that the relative impact of breeding habitat loss is at least three to six times greater than the impact of equivalent non-breeding habitat loss and therefore the steepest regional declines have likely been driven by the loss of breeding habitat. These results underscore the need for population-specific conservation strategies implemented throughout the annual cycle to reverse long-term declines.
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Pârâu, Liviu G., Diederik Strubbe, Emiliano Mori, Mattia Menchetti, Leonardo Ancillotto, André van Kleunen, Rachel L. White et al. « Rose-ringed Parakeet Psittacula krameri Populations and Numbers in Europe : A Complete Overview ». Open Ornithology Journal 9, no 1 (27 avril 2016) : 1–13. http://dx.doi.org/10.2174/1874453201609010001.
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Background: Alien species are one of the major causes contributing to biodiversity loss. In Europe, over 340 alien bird species have been recorded in the wild, of which 74 are established. Among 12 established alien parrot species in Europe, the Rose-ringed Parakeet (RRP) Psittacula krameri is the most abundant and widespread. Objective: Although one of the best documented alien vertebrates in Europe, historical and current datasets on RRP invasion success and demography have not been systematically collated and analysed. This paper therefore aims to bring together, verify and make available this information. Method: Existing distribution and demographic data for the RRP in Europe were collated from the following sources: (a) literature search; (b) bird sighting databases; (c) regional bird experts; (d) RRP roost counts. With this data, we evaluated population size and growth per population, country and the whole of Europe in the period 1965-2015. Results: The RRP is well established in Europe with at least 90 breeding populations in 10 countries, and a total population size of at least 85,000 birds as of 2015. For Western Europe, long-term demographic data indicate the species has grown considerably in number, although some populations have failed to persist. Data is scarce for countries in Central, Eastern and Northern Europe. Conclusion: Our synthesis reveals a positive demographic trend across Europe, although locally, some populations appear to have reached carrying capacity. Further research is needed to understand the mechanisms underlying RRP population growth in Europe, and methods amenable to citizen-scientists are urgently required to monitor population and range dynamics.
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Athrey, Giridhar, Nikolas Faust, Anne-Sophie Charlotte Hieke et I. Lehr Brisbin. « Effective population sizes and adaptive genetic variation in a captive bird population ». PeerJ 6 (18 octobre 2018) : e5803. http://dx.doi.org/10.7717/peerj.5803.
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Captive populations are considered a key component of ex situ conservation programs. Research on multiple taxa has shown the differential success of maintaining demographic versus genetic stability and viability in captive populations. In typical captive populations, usually founded by few or related individuals, genetic diversity can be lost and inbreeding can accumulate rapidly, calling into question their ultimate utility for release into the wild. Furthermore, domestication selection for survival in captive conditions is another concern. Therefore, it is crucial to understand the dynamics of population sizes, particularly the effective population size, and genetic diversity at non-neutral and adaptive loci in captive populations. In this study, we assessed effective population sizes and genetic variation at both neutral microsatellite markers, as well as SNP variants from the MHC-B locus of a captive Red Junglefowl population. This population represents a rare instance of a population with a well-documented history in captivity, following a realistic scenario of chain-of-custody, unlike many captive lab populations. Our analyses, which included 27 individuals comprising the entirety of one captive population show very low neutral and adaptive genetic variation, as well as low effective sizes, which correspond with the known demographic history. Finally, our study also shows the divergent impacts of small effective size and inbreeding in captive populations on microsatellite versus adaptive genetic variation in the MHC-B locus. Our study provides insights into the difficulties of maintaining adaptive genetic variation in small captive populations.
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Wheeler, Michael E., Jeb A. Barzen, Shawn M. Crimmins et Timothy R. Van Deelen. « Effects of territorial status and life history on Sandhill Crane (Antigone canadensis) population dynamics in south-central Wisconsin, USA ». Canadian Journal of Zoology 97, no 2 (février 2019) : 112–20. http://dx.doi.org/10.1139/cjz-2018-0135.
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Population growth rate in long-lived bird species is often most sensitive to changes in adult survival. Sandhill Cranes (Antigone canadensis (Linnaeus, 1758)) have long life spans, small broods, and delayed first reproduction. Only territorial adult Sandhill Cranes participate in breeding, and territory acquisition reflects the interplay between the availability of suitable territories and the variation in mortality of adult birds occupying those territories. We estimated vital rates of a population at equilibrium using long-term resightings data (2000–2014; n = 451 marked individuals) in a multistate mark–resight model and used a stage-structured projection matrix to assess how strongly territorial adult survival affects population growth rate. Elasticity analysis indicated territorial birds surviving and retaining territories had a 2.58 times greater impact on population growth compared with the next most important transition rate (survival of nonterritorial adults remaining nonterritorial). Knowing how changes in vital rates of various stage classes will differentially impact population growth rate allows for targeted management actions including encouraging growth in recovering populations, assessing opportunity for recreational harvest, or maintaining populations at a desired level. This study also highlights the value of collecting demographic data for all population segments, from which one can derive reproductive output or growth rate.
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GAO, SHUJING, YUMIN DING et JIANPING XIE. « ROLE OF DISEASE PROPAGATION IN MIGRATORY BIRD POPULATION ». International Journal of Biomathematics 05, no 03 (mai 2012) : 1260002. http://dx.doi.org/10.1142/s1793524512600029.
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Chatterjee considered a predator–prey model with avian migration in the migration prey population [S. Chatterjee, Alternative prey source coupled with prey recovery enhance stability between migratory prey and their predator in the presence of disease, Nonlinear Anal. Real World Appl. 11 (2010) 4415–4430]. In this paper, we modify and analyze the model by taking time dependent parameters and the general functional response into consideration. The conditions for the persistence of the system and the extinction of the disease are obtained. The global attractivity of the system is also studied. By numerical simulations, we find that the qualitative behavior of the system independent on the choice of the functional response. Moreover, it is observed that the infection rate, recruitment rate and the predation rate play a vital role in predicting the behavior of the dynamics.
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Thompson, D. B. A., D. J. Curtis et J. C. Smyth. « Patterns of association between birds and invertebrates in the Clyde Estuary ». Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 90 (1986) : 185–201. http://dx.doi.org/10.1017/s026972700000498x.
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SynopsisRelationships between feeding ecology, population dynamics and conservation of estuarine shorebirds are becoming better understood mainly as a result of detailed long-term studies of birds in the northwest European estuaries most vulnerable to industrial and agricultural developments. Until five years ago the tidal flats of the Clyde Estuary held internationally and nationally important populations of ducks (Anatinae) and waders (Charadrii). To understand the reasons for changes in bird distribution it is necessary to know more about the factors which determine distribution. In this paper we examine the pattern of association between the Clyde's birds and their prey by evaluating the extent to which the distribution of birds is related to that of benthic invertebrates, heterospecific birds, season and tidal state.Stepwise multiple regression analysis indicated that heterospecifics had effects on bird distributions over-riding those of prey. In summer, the significant independent variables explained 41–61% variation in bird density (number km−2) and 33% variation in bird feeding hours (bird-hours km−2); in winter they explained 17–35% and 29–32% respectively. The amount of variation explained was greater during flow than ebb tides, and the number of species for which some of the variation was explained was greater in winter than in summer. Three associations, each consisting of two bird species, are suggested: redshank with lapwing, dunlin with mallard, and shelduck with gulls. We provide explanations for some of the mechanisms underlying the above patterns and indicate areas for more detailed observational and experimental work. The integrity of the avian component of the estuarine ecosystem appears to be dependent on associations and interactions between birds as well as between birds and their prey. The associations are labile, and in many species stem from the effect of tidal movement on prey availability.
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Lawson, Becki, Robert A. Robinson, Mike P. Toms, Kate Risely, Susan MacDonald et Andrew A. Cunningham. « Health hazards to wild birds and risk factors associated with anthropogenic food provisioning ». Philosophical Transactions of the Royal Society B : Biological Sciences 373, no 1745 (12 mars 2018) : 20170091. http://dx.doi.org/10.1098/rstb.2017.0091.
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Provision of supplementary food for wild birds at garden feeding stations is a common, large-scale and year-round practice in multiple countries including Great Britain (GB). While these additional dietary resources can benefit wildlife, there is a concomitant risk of disease transmission, particularly when birds repeatedly congregate in the same place at high densities and through interactions of species that would not normally associate in close proximity. Citizen science schemes recording garden birds are popular and can integrate disease surveillance with population monitoring, offering a unique opportunity to explore inter-relationships between supplementary feeding, disease epidemiology and population dynamics. Here, we present findings from a national surveillance programme in GB and note the dynamism of endemic and emerging diseases over a 25-year period, focusing on protozoal (finch trichomonosis), viral (Paridae pox) and bacterial (passerine salmonellosis) diseases with contrasting modes of transmission. We also examine the occurrence of mycotoxin contamination of food residues in bird feeders, which present both a direct and indirect (though immunosuppression) risk to wild bird health. Our results inform evidence-based mitigation strategies to minimize anthropogenically mediated health hazards, while maintaining the benefits of providing supplementary food for wild birds. This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife’.
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Knape, Jonas, et Perry de Valpine. « Effects of weather and climate on the dynamics of animal population time series ». Proceedings of the Royal Society B : Biological Sciences 278, no 1708 (29 septembre 2010) : 985–92. http://dx.doi.org/10.1098/rspb.2010.1333.
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Weather is one of the most basic factors impacting animal populations, but the typical strength of such impacts on population dynamics is unknown. We incorporate weather and climate index data into analysis of 492 time series of mammals, birds and insects from the global population dynamics database. A conundrum is that a multitude of weather data may a priori be considered potentially important and hence present a risk of statistical over-fitting. We find that model selection or averaging alone could spuriously indicate that weather provides strong improvements to short-term population prediction accuracy. However, a block randomization test reveals that most improvements result from over-fitting. Weather and climate variables do, in general, improve predictions, but improvements were barely detectable despite the large number of datasets considered. Climate indices such as North Atlantic Oscillation are not better predictors of population change than local weather variables. Insect time series are typically less predictable than bird or mammal time series, although all taxonomic classes display low predictability. Our results are in line with the view that population dynamics is often too complex to allow resolving mechanisms from time series, but we argue that time series analysis can still be useful for estimating net environmental effects.
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Hemmings, Nicola, et Simon Evans. « Unhatched eggs represent the invisible fraction in two wild bird populations ». Biology Letters 16, no 1 (janvier 2020) : 20190763. http://dx.doi.org/10.1098/rsbl.2019.0763.
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Prenatal mortality is typically overlooked in population studies, which biases evolutionary inference by confounding selection and inheritance. Birds represent an opportunity to include this ‘invisible fraction’ if each egg contains a zygote, but whether hatching failure is caused by fertilization failure versus prenatal mortality is largely unknown. We quantified fertilization failure rates in two bird species that are popular systems for studying evolutionary dynamics and found that overwhelming majorities (99.9%) of laid eggs were fertilized. These systems thus present opportunities to eliminate the invisible fraction from life-history data.
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Ims, Rolf A., John-André Henden, Anders V. Thingnes et Siw T. Killengreen. « Indirect food web interactions mediated by predator–rodent dynamics : relative roles of lemmings and voles ». Biology Letters 9, no 6 (23 décembre 2013) : 20130802. http://dx.doi.org/10.1098/rsbl.2013.0802.
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Production cycles in birds are proposed as prime cases of indirect interactions in food webs. They are thought to be driven by predators switching from rodents to bird nests in the crash phase of rodent population cycles. Although rodent cycles are geographically widespread and found in different rodent taxa, bird production cycles appear to be most profound in the high Arctic where lemmings dominate. We hypothesized that this may be due to arctic lemmings inducing stronger predator responses than boreal voles. We tested this hypothesis by estimating predation rates in dummy bird nests during a rodent cycle in low-Arctic tundra. Here, the rodent community consists of a spatially variable mix of one lemming ( Lemmus lemmus ) and two vole species ( Myodes rufocanus and Microtus oeconomus ) with similar abundances. In consistence with our hypothesis, lemming peak abundances predicted well crash-phase nest predation rates, whereas the vole abundances had no predictive ability. Corvids were found to be the most important nest predators. Lemmings appear to be accessible to the whole predator community which makes them particularly powerful drivers of food web dynamics.
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Barrantes, Gilbert, et Luis Sandoval. « Effect of El Niño and La Niña on abundance of frugivorous and nectarivorous terrestrial birds in three tropical forests ». Revista de Biología Tropical 67, no 2SUPL (14 mai 2019) : S282—S297. http://dx.doi.org/10.15517/rbt.v67i2supl.37252.
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El Niño and La Niña climatic oscillations have dramatic effects on population dynamics and community structure of different animals. For marine birds, El Niño phenomenon drastically increases their mortality and reduces their reproductive success. In terrestrial ecosystems, the lack of long-term longitudinal data limits our understanding of the impact of El Niño and La Niña on bird populations and communities. We analyzed changes in abundance of frugivorous (large, medium, and small) and nectarivorous birds on three tropical forest types (lowland, premontane and montane) during El Niño, La Niña and neutral years using data from 16 Christmas’ Bird Counts in Costa Rica. Abundance of large and medium size frugivores increased during La Niña events, and the abundance of nectarivores during El Niño in the lowland forest, but neither of these events affected the abundance of small frugivores. In the montane forest, abundance of all four bird groups increased during El Niño, but decreased during La Niña events. Abundance of large, and small frugivores increased in the premontane forest during La Niña events, but other bird groups were not affected by La Niña. The abundance of small frugivores also increased during El Niño. We hypothesize that changes in abundance of frugivores and nectarivores during La Niña and El Niño events is probably correlated with fluctuations in food resources as it has been reported for other terrestrial tropical ecosystems.
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Tripet, Frédéric, et Heinz Richner. « DENSITY-DEPENDENT PROCESSES IN THE POPULATION DYNAMICS OF A BIRD ECTOPARASITECERATOPHYLLUS GALLINAE ». Ecology 80, no 4 (juin 1999) : 1267–77. http://dx.doi.org/10.1890/0012-9658(1999)080[1267:ddpitp]2.0.co;2.
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Camacho, Carlos, Jesús Martínez-Padilla, David Canal et Jaime Potti. « Long-term dynamics of phenotype-dependent dispersal within a wild bird population ». Behavioral Ecology 30, no 2 (8 janvier 2019) : 548–56. http://dx.doi.org/10.1093/beheco/ary195.
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Mougeot, F., S. M. Redpath, F. Leckie et P. J. Hudson. « The effect of aggressiveness on the population dynamics of a territorial bird ». Nature 421, no 6924 (février 2003) : 737–39. http://dx.doi.org/10.1038/nature01395.
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Grainger Hunt, W. « C. B. Moffat's anticipation of twenty-first century bird population dynamics theory ». Ibis 157, no 4 (8 septembre 2015) : 888–91. http://dx.doi.org/10.1111/ibi.12283.
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Dadam, Daria, Robert A. Robinson, Anabel Clements, Will J. Peach, Malcolm Bennett, J. Marcus Rowcliffe et Andrew A. Cunningham. « Avian malaria-mediated population decline of a widespread iconic bird species ». Royal Society Open Science 6, no 7 (juillet 2019) : 182197. http://dx.doi.org/10.1098/rsos.182197.
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Parasites have the capacity to affect animal populations by modifying host survival, and it is increasingly recognized that infectious disease can negatively impact biodiversity. Populations of the house sparrow ( Passer domesticus ) have declined in many European towns and cities, but the causes of these declines remain unclear. We investigated associations between parasite infection and house sparrow demography across suburban London where sparrow abundance has declined by 71% since 1995. Plasmodium relictum infection was found at higher prevalences (averaging 74%) in suburban London house sparrows than previously recorded in any wild bird population in Northern Europe. Survival rates of juvenile and adult sparrows and population growth rate were negatively related to Plasmodium relictum infection intensity. Other parasites were much less prevalent and exhibited no relationship with sparrow survival and no negative relationship with population growth. Low rates of co-infection suggested sparrows were not immunocompromised. Our findings indicate that P. relictum infection may be influencing house sparrow population dynamics in suburban areas. The demographic sensitivity of the house sparrow to P. relictum infection in London might reflect a recent increase in exposure to this parasite.
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Belder, Donna J., Jennifer C. Pierson, Karen Ikin et David B. Lindenmayer. « Beyond pattern to process : current themes and future directions for the conservation of woodland birds through restoration plantings ». Wildlife Research 45, no 6 (2018) : 473. http://dx.doi.org/10.1071/wr17156.
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Habitat loss as a result of land conversion for agriculture is a leading cause of global biodiversity loss and altered ecosystem processes. Restoration plantings are an increasingly common strategy to address habitat loss in fragmented agricultural landscapes. However, the capacity of restoration plantings to support reproducing populations of native plants and animals is rarely measured or monitored. This review focuses on avifaunal response to revegetation in Australian temperate woodlands, one of the world’s most heavily altered biomes. Woodland birds are a species assemblage of conservation concern, but only limited research to date has gone beyond pattern data and occupancy trends to examine whether they persist and breed in restoration plantings. Moreover, habitat quality and resource availability, including food, nesting sites and adequate protection from predation, remain largely unquantified. Several studies have found that some bird species, including species of conservation concern, will preferentially occupy restoration plantings relative to remnant woodland patches. However, detailed empirical research to verify long-term population growth, colonisation and extinction dynamics is lacking. If restoration plantings are preferentially occupied but fail to provide sufficient quality habitat for woodland birds to form breeding populations, they may act as ecological traps, exacerbating population declines. Monitoring breeding success and site fidelity are under-utilised pathways to understanding which, if any, bird species are being supported by restoration plantings in the long term. There has been limited research on these topics internationally, and almost none in Australian temperate woodland systems. Key knowledge gaps centre on provision of food resources, formation of optimal foraging patterns, nest-predation levels and the prevalence of primary predators, the role of brood parasitism, and the effects of patch size and isolation on resource availability and population dynamics in a restoration context. To ensure that restoration plantings benefit woodland birds and are cost-effective as conservation strategies, the knowledge gaps identified by this review should be investigated as priorities in future research.
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Barrett, Kyle, Christina M. Romagosa et Matthew I. Williams. « Long-Term Bird Assemblage Trends in Areas of High and Low Human Population Density ». Research Letters in Ecology 2008 (2008) : 1–4. http://dx.doi.org/10.1155/2008/202606.
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Urban areas are expanding globally, and the impact of high human population density (HHPD) on bird species richness remains unresolved. Studies primarily focus on species richness along an urban-to-rural gradient; however, some studies have analyzed larger-scale patterns and found results that contrast with those obtained at smaller scales. To move the discussion beyond static species richness patterns, we analyzed the effect of HHPD on bird assemblage dynamics (year-to-year extinction probability, turnover, changes in species richness) across the United States over a 25-year period. We found that bird assemblages in both high and low human population density areas changed significantly over the period of record. Specifically, bird assemblages increased in species richness on average. Assemblage change in areas of HHPD was not significantly different from assemblage change in areas with LHPD. These results suggest that human population density alone does not alter the persistence of avian assemblage patterns.
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Bowler, Diana E., Mikkel A. J. Kvasnes, Hans C. Pedersen, Brett K. Sandercock et Erlend B. Nilsen. « Impacts of predator-mediated interactions along a climatic gradient on the population dynamics of an alpine bird ». Proceedings of the Royal Society B : Biological Sciences 287, no 1941 (23 décembre 2020) : 20202653. http://dx.doi.org/10.1098/rspb.2020.2653.
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According to classic theory, species' population dynamics and distributions are less influenced by species interactions under harsh climatic conditions compared to under more benign climatic conditions. In alpine and boreal ecosystems in Fennoscandia, the cyclic dynamics of rodents strongly affect many other species, including ground-nesting birds such as ptarmigan. According to the ‘alternative prey hypothesis’ (APH), the densities of ground-nesting birds and rodents are positively associated due to predator–prey dynamics and prey-switching. However, it remains unclear how the strength of these predator-mediated interactions change along a climatic harshness gradient in comparison with the effects of climatic variation. We built a hierarchical Bayesian model to estimate the sensitivity of ptarmigan populations to interannual variation in climate and rodent occurrence across Norway during 2007–2017. Ptarmigan abundance was positively linked with rodent occurrence, consistent with the APH. Moreover, we found that the link between ptarmigan abundance and rodent dynamics was strongest in colder regions. Our study highlights how species interactions play an important role in population dynamics of species at high latitudes and suggests that they can become even more important in the most climatically harsh regions.
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Tripet, Frederic, et Heinz Richner. « Density-Dependent Processes in the Population Dynamics of a Bird Ectoparasite Ceratophyllus gallinae ». Ecology 80, no 4 (juin 1999) : 1267. http://dx.doi.org/10.2307/177073.
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Bourouiba, L., Jianhong Wu, S. Newman, J. Takekawa, T. Natdorj, N. Batbayar, C. M. Bishop, L. A. Hawkes, P. J. Butler et M. Wikelski. « Spatial dynamics of bar-headed geese migration in the context of H5N1 ». Journal of The Royal Society Interface 7, no 52 (4 août 2010) : 1627–39. http://dx.doi.org/10.1098/rsif.2010.0126.
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Virulent outbreaks of highly pathogenic avian influenza (HPAI) since 2005 have raised the question about the roles of migratory and wild birds in the transmission of HPAI. Despite increased monitoring, the role of wild waterfowl as the primary source of the highly pathogenic H5N1 has not been clearly established. The impact of outbreaks of HPAI among species of wild birds which are already endangered can nevertheless have devastating consequences for the local and non-local ecology where migratory species are established. Understanding the entangled dynamics of migration and the disease dynamics will be key to prevention and control measures for humans, migratory birds and poultry. Here, we present a spatial dynamic model of seasonal migration derived from first principles and linking the local dynamics during migratory stopovers to the larger scale migratory routes. We discuss the effect of repeated epizootic at specific migratory stopovers for bar-headed geese ( Anser indicus ). We find that repeated deadly outbreaks of H5N1 on stopovers during the autumn migration of bar-headed geese could lead to a larger reduction in the size of the equilibrium bird population compared with that obtained after repeated outbreaks during the spring migration. However, the opposite is true during the first few years of transition to such an equilibrium. The age-maturation process of juvenile birds which are more susceptible to H5N1 reinforces this result.
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Sæther, Bernt–Erik, et Steinar Engen. « Pattern of variation in avian population growth rates ». Philosophical Transactions of the Royal Society of London. Series B : Biological Sciences 357, no 1425 (29 septembre 2002) : 1185–95. http://dx.doi.org/10.1098/rstb.2002.1119.
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A central question in population ecology is to understand why population growth rates differ over time. Here, we describe how the long–term growth of populations is not only influenced by parameters affecting the expected dynamics, for example form of density dependence and specific population growth rate, but is also affected by environmental and demographic stochasticity. Using long–term studies of fluctuations of bird populations, we show an interaction between the stochastic and the deterministic components of the population dynamics: high specific growth rates at small densities r 1 are typically positively correlated with the environmental variance σ e 2 . Furthermore, θ, a single parameter describing the form of the density regulation in the theta–logistic density–regulation model, is negatively correlated with r 1 . These patterns are in turn correlated with interspecific differences in life–history characteristics. Higher specific growth rates, larger stochastic effects on the population dynamics and stronger density regulation at small densities are found in species with large clutch sizes or high adult mortality rates than in long–lived species. Unfortunately, large uncertainties in parameter estimates, as well as strong stochastic effects on the population dynamics, will often make even short–term population projections unreliable. We illustrate that the concept of population prediction interval can be useful in evaluating the consequences of these uncertainties in the population projections for the choice of management actions.
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Gashek, Valeria A., et Valeriy D. Zakharov. « Long-term dynamics of avifauna and bird population of Chelyabinsk International Airport Balandino, Russia ». Ecosystem Transformation 5, no 1 (2022) : 27–49. http://dx.doi.org/10.23859/estr-211117.
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Over 30-year study period (1990–2021), 144 bird species, including 54 nesting species, were registered on the territory of the Chelyabinsk International Airport Balandino. Total bird population density varied from 147 ind./km² in 1990 to 215 ind./km² in 2020. In different years, dominant species in this area were Alauda arvensis, Motacilla flava, Saxicola rubetra, S. torquata, and Passer montana. In the first years of research, a significant decrease in the number of the most widespread species (Corvus frugilegus, C. monedula, Columba livia, Larus barabensis, L. canus, and L. ridibundus), crossing the airfield during seasonal and diurnal (forage) migrations, was revealed. This was caused both by decrease of population of some species (C. frugilegus) in the European and Ural-Siberian parts of their range, and by the deterioration of the state of forage lands on the airport territory after the elimination of solid waste landfills and a decrease of farmland areas nearby.
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Barry Baker, G., E. Belinda Dettmann et Stephen J. Wilson. « Fire and its impact on avian population dynamics ». Pacific Conservation Biology 3, no 3 (1997) : 206. http://dx.doi.org/10.1071/pc970206.
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Survival rate, population size, recruitment and probability of capture, derived from a long-term study of 20 passerine species in wet sclerophyll forest near Canberra, were used to measure the impact of a high intensity wildfire which burnt 70% of the study area. The wildfire significantly affected the population size of 13 species for a period of up to six years following the fire. Survival and recruitment were the least sensitive measures of impact and indicated a significant response to fire for only 2 of 10 species. We detected measurable effects of the fire for 17 of the 20 species studied. Many of these species had returned to prefire levels within three years, but for nine species the effects were still apparent six years later. Mark-recapture methodology provides an effective way of measuring the impact of fire regimes in forest environments. Long-term monitoring programmes should be established in fire-prone forest environments to contribute toward our understanding of fire, and its effect on avian populations. Such programmes have resource implications and researchers are urged to encourage the participation of the amateur bird banding community to contribute to such projects.
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Bonnet, Timothée, Michael B. Morrissey, Pierre de Villemereuil, Susan C. Alberts, Peter Arcese, Liam D. Bailey, Stan Boutin et al. « Genetic variance in fitness indicates rapid contemporary adaptive evolution in wild animals ». Science 376, no 6596 (27 mai 2022) : 1012–16. http://dx.doi.org/10.1126/science.abk0853.
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The rate of adaptive evolution, the contribution of selection to genetic changes that increase mean fitness, is determined by the additive genetic variance in individual relative fitness. To date, there are few robust estimates of this parameter for natural populations, and it is therefore unclear whether adaptive evolution can play a meaningful role in short-term population dynamics. We developed and applied quantitative genetic methods to long-term datasets from 19 wild bird and mammal populations and found that, while estimates vary between populations, additive genetic variance in relative fitness is often substantial and, on average, twice that of previous estimates. We show that these rates of contemporary adaptive evolution can affect population dynamics and hence that natural selection has the potential to partly mitigate effects of current environmental change.
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J. J. F. Davies, Stephen. « Boom & ; Bust : Bird Stories for a Dry Country ». Pacific Conservation Biology 16, no 1 (2010) : 70. http://dx.doi.org/10.1071/pc100070.
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As the subtitle says, this is a book of bird stories. The overall theme examines the population dynamics and evolution of some Australian inland birds in 12 separate essays, each by a different author or group of authors. It is apparent that the dates of preparation of these chapters cover an extended time period, one prepared by an author who died in 2001, and there is little attempt to integrate the stories. Each of the essays is well referenced and written by a respected authority on the bird, birds or topic that are the subject of the essay. In this way the book is authoritative, but it is also innovative, because it is clear that peer review has not been applied, or if applied then applied gently, because the authors have been allowed to speculate on the interpretations of the data they present. Modern journal editors and peer reviewers do their best to eliminate such speculation and yet it is from the presentation of such untested ideas that inquiry begins and science advances. The editors are to be applauded for taking this approach.
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Liu, Sanhong, Liuyong Pang, Shigui Ruan et Xinan Zhang. « Global Dynamics of Avian Influenza Epidemic Models with Psychological Effect ». Computational and Mathematical Methods in Medicine 2015 (2015) : 1–12. http://dx.doi.org/10.1155/2015/913726.
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Cross-sectional surveys conducted in Thailand and China after the outbreaks of the avian influenza A H5N1 and H7N9 viruses show a high degree of awareness of human avian influenza in both urban and rural populations, a higher level of proper hygienic practice among urban residents, and in particular a dramatically reduced number of visits to live markets in urban population after the influenza A H7N9 outbreak in China in 2013. In this paper, taking into account the psychological effect toward avian influenza in the human population, a bird-to-human transmission model in which the avian population exhibits saturation effect is constructed. The dynamical behavior of the model is studied by using the basic reproduction number. The results demonstrate that the saturation effect within avian population and the psychological effect in human population cannot change the stability of equilibria but can affect the number of infected humans if the disease is prevalent. Numerical simulations are given to support the theoretical results and sensitivity analyses of the basic reproduction number in terms of model parameters that are performed to seek for effective control measures for avian influenza.
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McCrimmon, Donald A., Slawomir T. Fryska, John C. Ogden et Gregory S. Butcher. « NONLINEAR POPULATION DYNAMICS OF SIX SPECIES OF FLORIDA CICONIIFORMES ASSESSED BY CHRISTMAS BIRD COUNTS ». Ecological Applications 7, no 2 (mai 1997) : 581–92. http://dx.doi.org/10.1890/1051-0761(1997)007[0581:npdoss]2.0.co;2.
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Vauk, Gottfried, Johannes Prüter et Eike Hartwig. « Long-term population dynamics of breeding bird species in the German Wadden Sea area ». Helgoländer Meeresuntersuchungen 43, no 3-4 (septembre 1989) : 357–65. http://dx.doi.org/10.1007/bf02365896.
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Fischer, Jason D., et James R. Miller. « Direct and indirect effects of anthropogenic bird food on population dynamics of a songbird ». Acta Oecologica 69 (novembre 2015) : 46–51. http://dx.doi.org/10.1016/j.actao.2015.08.006.
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Anderies, John M., Madhusudan Katti et Eyal Shochat. « Living in the city : Resource availability, predation, and bird population dynamics in urban areas ». Journal of Theoretical Biology 247, no 1 (juillet 2007) : 36–49. http://dx.doi.org/10.1016/j.jtbi.2007.01.030.
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Ethier, Danielle M., Nicola Koper et Thomas D. Nudds. « Spatiotemporal variation in mechanisms driving regional-scale population dynamics of a Threatened grassland bird ». Ecology and Evolution 7, no 12 (27 avril 2017) : 4152–62. http://dx.doi.org/10.1002/ece3.3004.
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Burgess, Malcolm D., Malcolm A. C. Nicoll, Carl G. Jones et Ken Norris. « Restricted dispersal reduces the strength of spatial density dependence in a tropical bird population ». Proceedings of the Royal Society B : Biological Sciences 275, no 1639 (19 février 2008) : 1209–16. http://dx.doi.org/10.1098/rspb.2007.1751.
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Spatial processes could play an important role in density-dependent population regulation because the disproportionate use of poor quality habitats as population size increases is widespread in animal populations—the so-called buffer effect. While the buffer effect patterns and their demographic consequences have been described in a number of wild populations, much less is known about how dispersal affects distribution patterns and ultimately density dependence. Here, we investigated the role of dispersal in spatial density dependence using an extraordinarily detailed dataset from a reintroduced Mauritius kestrel ( Falco punctatus ) population with a territorial (despotic) breeding system. We show that recruitment rates varied significantly between territories, and that territory occupancy was related to its recruitment rate, both of which are consistent with the buffer effect theory. However, we also show that restricted dispersal affects the patterns of territory occupancy with the territories close to release sites being occupied sooner and for longer as the population has grown than the territories further away. As a result of these dispersal patterns, the strength of spatial density dependence is significantly reduced. We conclude that restricted dispersal can modify spatial density dependence in the wild, which has implications for the way population dynamics are likely to be impacted by environmental change.