Patterns of distribution and abundance of Greater Snow Geese on Bylot Island, Nunavut, Canada 1983-1998

Abstract

To m onitor the num bers and distribution of Greater Snow Geese at the largest breeding colony in the eastern Canadian High Arctic, surveys were conducted on Bylot Island at five year intervals from 1983 to 1998.The surveys were conducted during the brood-rearing period using a stratified sam pling procedure and aerial photog raphy.The total num ber of adult geese increased from 25,500 (SE 2582) in 1983 to 69,500 [SE 8645) in 1993 (a year of exceptionally high breeding effort and breeding success) before dropping slightly in 1998.The num ber of goslings also increased from 26,500 (SE 2320) in 1983 to 86,500 (SE 8147) in 1993, and also dropped slightly in 1998.In years of high breeding success (1983 and 1993) the adult popu lation on Bylot Island represented 14% of the entire world population of Greater Snow Geese.The adult population on Bylot Island between 1983 and 1998 showed an aver age annual rate of increase of 7%, sim ila r to the 9% increase recorded for the entire population.Brood densi ties varied from a low of 0.8 broods km 2 in the poorest quality habitats in 1983 to 29.9 broods k rrf2 in the best habitats in 1993, but an increasing trend was evident in all habitat strata over the course of the study.A large proportion (63%) of the surface area of the colony accommodated only very low brood densities in 1983, but by 1993 the proportion occu * .