SPACE AND HABITAT USE BY GREATER SNOW GOOSE BROODS ON BYLOT ISLAND, NORTHWEST-TERRITORIES

The brood-rearing season is a critical time for arctic-breeding geese because plant production is low and the growing season short. Thus, pa rental geese must efficiently exploit resources if young are to acquir e adequate size and condition in preparation for fall migration. Curre nt knowledge of habitat and space use by arctic-breeding geese is limi ted to some observations of unmarked birds. Thus, we studied habitat a nd space use of individual radio-marked greater snow geese (Chen caeru lescens atlantica) in a high arctic environment. We radiotracked 20 go ose families throughout the brood-rearing period in July and August 19 89 and 1990, in a 70-km2 area of wet tundra and upland habitats on Byl ot Island, Northwest Territories. Average use of habitat by radio-mark ed families was similar to that of unmarked geese, but individual spac e and habitat use patterns varied considerably. We identified 3 space use groups: sedentary (use of a single concentrated area of activity) families, shifters (use of >1 concentrated area), and wanderers (no co ncentrated area of activity). Home-range sizes for the 3 groups averag ed 680, 1,660, and 1,820 ha, respectively. Initial movements between t he nest and brood-rearing site ranged from <1 to 5 km for individual f amilies in all 3 groups, but subsequent movements were greater for shi fters (P < 0.001) and wanderers (P < 0.001) than for sedentary familie s. Sedentary families used a greater proportion of habitats with abund ant ponds and lakes, compared with families in the other 2 groups, whi ch used more upland habitat. Young of sedentary families tended to hat ch earlier than those of shifters or wanderers, suggesting that sedent ary females were more experienced individuals. Differences in use of h abitat among families may account for some variation observed in body mass of goslings captured prior to fledging.