FALL FOOD-HABITS OF AMERICAN WIGEON AT LONG POINT, LAKE ERIE, ONTARIO

We studied food habits of an abundant migrant, the American wigeon (An as americana), staging during the 1998 fall migration at Long Point, a World Biosphere Reserve and a Ramsar site on the north shore of Lake Erie. Food samples from 149 wigeons were analyzed; stems and leaves of aquatic plants (predominantly submerged macrophytes) comprised over 9 2% aggregate dry mass of the diet, seeds made up 7.8%, and animal matt er 0.6%. A diverse array of plant species was identified; however, res ults indicate that wigeons were showing selectivity in plant species c onsumed. Stems and leaves of muskgrass (Chara spp.), elodea (Elodea ca nadensis) and bushy pondweeds (Najas flexilus and N. guadalupensis) (a ggregate percent dry mass 37%, 22%, and 18% for proventriculi, and 15% , 12%, and 38% for gizzards, respectively) comprised the bulk of the d iet, although neither bushy pondweed nor elodea wholly dominated subme rged macrophyte communities. Several submerged macrophytes, such as co ontail (Ceratophyllum demersum) and pondweeds (Potamogeton spp.) which are common and widespread at Long Point and reported frequently as im portant in the diet of American wigeons elsewhere, were not found at a ll or only in trace amounts. Some sex, age, and seasonal differences i n diet were detected, Chara spp. and tubers were eaten more frequently by adults than by immatures, Elodea canadensis was eaten in late fall by females but not by males, immatures ate Myriophyllum spicatum seed s more frequently than did adults, and Najas spp. was consumed more in late fall than in early fall.