Ardea
Official journal of the Netherlands Ornithologists' Union

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Fox A.D., Francis I.S. & Bergersen E. (2006) Diet and habitat use of Svalbard Pink-footed Geese Anser brachyrhynchus during arrival and pre-breeding periods in Adventdalen. ARDEA 94 (3): 691-699
The feeding behaviour of Pink-footed Geese Anser brachyrhynchus was studied in Adventdalen, Svalbard during 1528 May 2004 to determine habitat use of newly arrived birds based on their distribution in relation to the major vegetation types present. Goose numbers increased from initial arrival on 15 May to 380440 during 2328 May, with a brief arrival peak of 990 on 20 May. Geese fed initially on grass-rich communities associated with gravel out-wash fans, but shifted to wet meadow habitats as the thaw progressed, and increasingly used moss tundra and heath habitats after 22 May. Less than 20% of observed geese fed by grubbing the substrate prior to 21 May, but more than 85% did so from 24 May onwards as rising air temperatures exceeded freezing point and the substrate progressively thawed, permitting excavation of subterranean plant storage organs. This pattern was reflected in the diet based on examination of epidermal fragments in the droppings, which showed geese initially fed on above ground dead material from the previous growing season (most abundant in the productive out-wash fans). However, as the substrate thawed, from 22 May geese fed increasingly on the more nutritious Equisetum spp. and finally on below-ground storage organs of Bistorta viviparum as these became available with substrate thaw. The implications of these changes are discussed in the context of the energetic implications for arriving birds and their subsequent reproductive output.


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