Satellite tracking on the flyways of brown-headed gulls and their potential role in the spread of highly pathogenic avian influenza H5N1 virus.

Brown-headed gulls (Larus brunnicephalus), winter visitors of Thailand, were tracked by satellite telemetry during 2008-2011 for investigating their roles in the highly pathogenic avian influenza (HPAI) H5N1 virus spread. Eight gulls negative for influenza virus infection were marked with solar-powered satellite platform transmitters at Bang Poo study site in Samut Prakarn province, Thailand; their movements were monitored by the Argos satellite tracking system, and locations were mapped. Five gulls completed their migratory cycles, which spanned 7 countries (China, Bangladesh, India, Myanmar, Thailand, Cambodia, and Vietnam) affected by the HPAI H5N1 virus.

Fundamental limits to the accuracy of deuterium isotopes for identifying the spatial origin of migratory animals.

Deuterium isotope analyses have revolutionized the study of migratory connectivity because global gradients of deuterium in precipitation (deltaD(P)) are expressed on a continental scale. Several authors have constructed continental scale base maps of deltaD(P) to provide a spatial reference for studying the movement patterns of migratory species and, although they are very useful, these maps present a static, 40-year average view of the landscape that ignores much underlying inter-annual variation. To more fully understand the consequences of this underlying variation, we analyzed the GNIP deuterium data, the source for all current deltaD(P) maps, to estimate the minimum separation in deltaD(P) (and latitude) necessary to conclude with a given level of confidence that distinct deltaD(P) values represent different geographic sites.