Current status and recent dynamics of the Black Brant Branta bernicla breeding population

Abstract

We summarize current knowledge about the distribution o f Pacific Black Brant and recent dynamics o f colonies, particularly on the Yukon-Kuskokwim (Y-K) Delta, Alaska.About 20,000 nests are required to produce the number o f young in the autumn flight using estimates o f clutch size, hatching success and gosling survival based on colonies on the Y-K Delta.More than 80% of the nests in the population can be accounted for currently on the Y-K Delta.Most moulting individuals that did not breed, or were unsuccessful, are unaccounted for in late summer.Numbers o f Black Brant nesting in major colonies on the Y-K Delta declined >60% in the early 1980s, most likely as a result o f local subsistence harvest combined with predation by arctic foxes.Effective management of this population requires a better understanding o f the distribution o f breeding and moulting birds, the importance of breeding habitat to colony dynamics and the role o f both sport and subsistence harvest in population dynamics.