Birds migrate over vast distances at substantial costs. The highly dynamic nature of the air makes the selection of the best travel route difficult. We investigated to what extent migratory birds may optimise migratory route choice with respect to wind, and if route choice can be subject to natural selection. Following the optimal route, calculated using 21 years of empirical global wind data, ...

It is increasingly acknowledged that migratory birds, notably waterfowl, play a critical role in the maintenance and spread of influenza A viruses. In order to elucidate the epidemiology of influenza A viruses in their natural hosts, a better understanding of the pathological effects in these hosts is required. Here we report on the feeding and migratory performance of wild migratory Bewick's s...

T initial outbreak of West Nile virus (WNV; family Flaviviridae, genus Flavivirus) in the Western Hemisphere took place in New York in 1999, with deaths observed in humans, horses, and numerous species of wild birds (1). Since then, this virus has spread rapidly across North America (2,3). Migratory birds are suspected of being responsible for the rapid spread of WNV through North America (4), ...

Blood parasites (Haemosporidia) are thought to impair the flight performance of infected animals, and therefore, infected birds are expected to differ from their non-infected counterparts in migratory capacity. Since haemosporidians invade host erythrocytes, it is commonly assumed that infected individuals will have compromised aerobic capacity, but this has not been examined in free-living bir...

Migratory species are in rapid decline globally. Although most mortality in long-distance migrant birds is thought to occur during migration, evidence of conditions on migration affecting breeding population sizes has been completely lacking. We addressed this by tracking 42 male Common Cuckoos from the rapidly declining UK population during 56 autumn migrations in 2011-14. Uniquely, the birds ...

BACKGROUND Highly pathogenic avian influenza A (HPAI) H5N1 viruses have infected poultry and wild birds on three continents with more than 600 reported human cases (59% mortality) since 2003. Wild aquatic birds are the natural reservoir for avian influenza A viruses, and migratory birds have been documented with HPAI H5N1 virus infection. Since 2005, clade 2.2 HPAI H5N1 viruses have spread from...

NH 03755-3576, USA. Migration – the regular seasonal movement of individuals, often from a breeding location to a nonbreeding location and back – is a common and taxonomically widespread phenomenon in nature, and is particularly common among birds. An important, but unresolved issue in the study of migratory birds is the extent to which individuals from the same breeding area migrate to the sam...