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Migrating birds face many perils as they travel between breeding and wintering grounds each year. Migration is a dangerous part of a bird's life cycle, with many trade-offs; birds receive benefits from wintering and breeding in better quality habitats, at the price of higher predation risks and greater energy expenditure. Hazards during migration include storms, hunting, collisions with manmade objects such as wind turbines, and starvation. The risk of starvation is increased when stopover sites are lost through climate change or loss of habitat to development or agriculture. Mortality on both breeding and wintering grounds may be increased for similar reasons. ==Context== Migrants tend to travel away from polar and temperate zones in the winter because of low temperatures and shortage of food in their breeding areas.〔Newton, I. (2007). (Weather related mass-mortality events in migrants ). British Ornithologists Union, 149, 453-467.〕〔Buskirk, J. V., Mulvihill, R. S., & Leberman, R. C. (2012). (Phenotypic plasticity alone cannot explain climate-induced change in avian migration timing ). ''Ecology and Evolution'', 2(10), 2430-2437.〕 During spring migration, birds return to their breeding sites to exploit the temporary superabundance of food, allowing them to raise more young.〔Newton, I. (2006). (Can conditions experienced during migration limit the population levels of birds? ). ''Journal of Ornithology'', 147(2), 146-166.〕 Many populations of migratory birds are in serious decline. Anthropogenic reasons for this include deforestation and habitat loss, hunting, pesticide uses, urbanization and climate change.〔Hutto, R. L. (1988). (Is tropical deforestation responsible for the reported declines in neotropical migrant populations ). ''American Birds'', 42, 375-379.〕 Identifying and understanding the processes and perils can allow us to implement effective management and conservation strategies for these species.〔Faaborg, J., Levey, D. J., Johnson, D. H., Holmes, R. T., Anders, A. D., Bildstein, K. L., et al. (2010). (Conserving Migratory Land Birds In The New World: Do We Know Enough? ). ''Ecological Applications'', 20(2), 398-418.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bird migration perils」の詳細全文を読む スポンサード リンク
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