نتایج جستجو برای: wintering

تعداد نتایج: 2246  

Journal: :Vector borne and zoonotic diseases 2012
Nichola J Hill John Y Takekawa Carol J Cardona Brandt W Meixell Joshua T Ackerman Jonathan A Runstadler Walter M Boyce

The spread of avian influenza viruses (AIV) in nature is intrinsically linked with the movements of wild birds. Wild birds are the reservoirs for the virus and their migration may facilitate the circulation of AIV between breeding and wintering areas. This cycle of dispersal has become widely accepted; however, there are few AIV studies that present cross-seasonal information. A flyway perspect...

2016
Rien E. van Wijk Silke Bauer Michael Schaub

Migratory birds are often faithful to wintering (nonbreeding) sites, and also migration timing is usually remarkably consistent, that is, highly repeatable. Spatiotemporal repeatability can be of advantage for multiple reasons, including familiarity with local resources and predators as well as avoiding the costs of finding a new place, for example, nesting grounds. However, when the environmen...

2003
Kristin L. Laidre Mads Peter Heide-Jørgensen Rune Dietz Roderick C. Hobbs Ole A. Jørgensen

Variation in resource selection among sub-populations may elucidate differences in fitness and life history strategies. Specifically for top marine predators, differences in movements and behavior may result from responses to variation in a patchy, dynamic environment. Satellite-linked time-depth recorders (SLTDRs) were used to examine differences in narwhal Monodon monoceros diving behavior an...

Journal: :Ecotoxicology 2010
Michael A Yates Mark R Fuller Charles J Henny William S Seegar Jaqueline Garcia

Locations of contaminant exposure for nesting migratory species are difficult to fully understand because of possible additional sources encountered during migration or on the wintering grounds. A portion of the migratory white-faced ibis (Plegadis chihi) nesting at Carson Lake, Nevada continues to be exposed to dichloro-diphenyldichloro-ethylene (DDE) with no change, which is unusual, observed...

2016
Pedro M. Lourenço José A. Alves Jeroen Reneerkens AH Jelle Loonstra Peter M. Potts José P. Granadeiro Teresa Catry

Many migratory bird species show high levels of site fidelity to their wintering sites, which confers advantages due to prior knowledge, but may also limit the ability of the individual to move away from degrading sites or to detect alternative foraging opportunities. Winter site fidelity often varies among age groups, but sexual differences have seldom been recorded in birds. We studied a popu...

2018
Diann J. Prosser Changqing Ding R. Michael Erwin Taej Mundkur Jeffery D. Sullivan Erle C. Ellis

Background: A number of conservation and societal issues require understanding how species are distributed on the landscape, yet ecologists are often faced with a lack of data to develop models at the resolution and extent desired, resulting in inefficient use of conservation resources. Such a situation presented itself in our attempt to develop waterfowl distribution models as part of a multi-...

2012
Keith A. Hobson Steven L. Van Wilgenburg Theunis Piersma Leonard I. Wassenaar

BACKGROUND The ability to connect breeding, stopover and wintering locations of populations of migratory birds greatly enhances our understanding of the phenomenon of migration and improves our chances of effectively conserving these species. Among Palearctic-Afrotropical migratory species, aerial insectivores like the house martin (Delichon urbicum) are sensitive to factors influencing the ava...

2000
D. A. CLARK W. CARTER B. WALSH C. D. WAUGH

Concern at the effect of winter pasture residuals on pasture productivity led to the comparison of different wintering systems at the DRC No. 3 Dairy from May-December 1993. Three farmlets were designed to have 2000 kg DM/ha average farm cover at calving, but with pastures grazed to either 900, 1400 or 1800 kg DM/ha at least once during the winter. A fourth farmlet was spelled from grazing from...

Journal: :Proceedings. Biological sciences 2014
Christiane Trierweiler Raymond H G Klaassen Rudi H Drent Klaus-Michael Exo Jan Komdeur Franz Bairlein Ben J Koks

Knowledge about migratory connectivity, the degree to which individuals from the same breeding site migrate to the same wintering site, is essential to understand processes affecting populations of migrants throughout the annual cycle. Here, we study the migration system of a long-distance migratory bird, the Montagu's harrier Circus pygargus, by tracking individuals from different breeding pop...

2013
Gabriel J. Colorado Paul B. Hamel Amanda D. Rodewald David Mehlman

– Recent population declines have prompted the International Union for the Conservation of Nature to list Cerulean Warbler (Setophaga cerulea: Parulidae) as a Vulnerable species. It is believed that this decline may be related to habitat loss through its entire range, mainly due to deforestation and degradation of its habitats. In response, members of El Grupo Cerúleo, a subcommittee of the Cer...

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