Summer foods of lesser scaup in subarctic taiga

Reports on the food of 25 adult and 38 juvenile Aythya affinis, collected in June-Sept 1967 along the Yellowknife Highway north of Great Slave Lake. The vegetation, physiography and ponds of the area, the collecting and statistical methods are briefly described. Approx 99% of the scaup diet was animal material; juveniles in mid-summer fed on freeswimming organisms such as Chaoborinae (phantom midges) and Conchostraca (clam shrimps); in late summer they, as did adults in June, fed on bottom organisms such as amphipods, odonates and corixids. Seeds, copepods and cladocerans were seldom or never eaten.