La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Status in Brent Goose in northwest Yakutia, East Siberia
Auteurs :	E. E. Syroechkovski, Auteur ; C. Zoeckler, Auteur ; E. Lappo, Auteur
Type de document :	Article
Dans :	British Birds (91(12) Dec., 1998)
Article en page(s) :	565-572
Résumé :	During June-July 1997, five colonies of Brent Geese Branta bernicla were visited in northwest Yakutia, East Siberia: three (total about 132 pairs) in the Olenyok delta and two (22 pairs) in the western Lena delta. Colonies varied in size from ten to 90 pairs. At all sites, both the nominate race bernicla and the race nigricans were found, the proportion of nominate varying from 15% in the east to over 95% in the west; eight mixed pairs were located, with five individuals showing intermediate characters. Ringing recoveries confirm the presence of two populations, one migrating to the Pacific coast of America and the other to northwest Europe. Populations of nominate bernicla and American nigricans are increasing, the latter also expanding westwards in Eastern Siberia, whereas the small Asian-Pacific population of nigricans remains in decline as a result of hunting pressure on passage and in winter. The discovery of mixed colonies of the two races counters suggestions that these forms should be treated as different species.

Lundi , mardi et jeudi de 9h à 12h et de 13h à 17h00 : ouverture au public ...