Foraging characteristics of Canada geese on the Nisutlin River delta, Yukon

• Published in: Canadian Journal of Zoology
• Main Authors: Coleman, T. S., Boag, D. A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1987
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Yukon; Canada; Branta canadensis
• Online Access: http://dx.doi.org/10.1139/z87-356; http://www.nrcresearchpress.com/doi/pdf/10.1139/z87-356

Food selection by Canada geese (Branta canadensis), staging in the autumn on the Nisutlin River delta in the south central Yukon Territory, was investigated between August and October of 1981, 1982, and 1983. Three distinct plant associations were used by the foraging geese: an aquatic association in which rhizomes of Potamogeton richardsonii, the dominant species, were eaten; a terrestrial and more vegetatively complex association in which Equisetum palustre was the main plant taken; and an association of almost pure stands of Equisetum fluviatile in wet depressions behind old river levees. Availability of these feeding zones depended on water levels on the delta. When water levels were low (October 1982), all feeding zones were available, yet the geese fed almost entirely in the Potamogeton zone, indicating a preference for that zone. At intermediate water levels, Potamogeton richardsonii was no longer available and the geese grazed on the complex vegetative zone, taking Equisetum palustre, Ranunculus reptans, and Eleocharis palustris in the ratio of their relative availability (85:10:5). Only when water levels were high did the geese graze exclusively in the Equisetum fluviatile zone, the least preferred.