Habitat Conditions, Grizzly Bear Predation of Nests, and Spring Use of the Anderson River Delta by Lesser Snow Geese and Brant, 2005–2006

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Numbers of Lesser Snow Goose (Chen caerulescens caerulescens) and Black Brant (Branta bernicla nigricans) nesting at the Anderson River Delta Migratory Bird Sanctuary (ARDMBS), Northwest Territories, have declined substantially over the past decade or longer. Hypothesized causes of the declines include loss of nesting habitat, nest predation by grizzly bears (Ursus arctos horribilis) or other predators, and human disturbance. The present investigation was carried out in the springs of 2005 and 2006 to examine possible causes of the population decline, evaluate current use of the sanctuary by geese, and describe current habitat conditions within a 44 km2 study area at ARDMBS.

Based on our findings, earlier investigations at ARDMBS, and research carried out elsewhere along the Beaufort Sea coast, it is apparent that salt-water flooding is a primary cause of the vegetation loss. Vegetation loss may have been further exacerbated by the feeding activities of large numbers of migrant Snow Geese. The disappearance of plant cover now limits the capacity of the outer delta to support nesting geese. As a result, Snow Goose nests are now concentrated in the remaining well-vegetated areas further inland, where they are accessible to foraging grizzly bears.

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  • Author: Environment Canada
  • Language of Document: Separate English/French
  • Document Type: Report
  • Cat. No.: CW69-5/523E
  • ISBN: 978-1-100-21415-3
  • Size: 21.6 X 28
  • Year: 2013
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