Effects of water quality on habitat use by lesser scaup (Aythya affinis) broods in the boreal Northwest Territories, Canada

Issue Title: Theme: Limnology and Aquatic Birds: Proceedings of the Fourth Conference Working Group on Aquatic Birds of Societas Internationalis Limnologiae (SIL), Sackville, New Brunswick, Canada, August 3-7, 2003 Populations of lesser scaup (Aythya affinis), an abundant duck in the northwestern boreal forest of Canada, have declined markedly over the past few decades. The limnological characteristics of northern wetlands used by lesser scaup and other waterfowl are inadequately documented and the possible effects of habitat quality or other factors on the use of water bodies by scaup are poorly understood. Waterfowl and limnological data, collected on a 38 km^sup 2^ area roadside study area near Yellowknife, Northwest Territories, were used to describe the characteristics of ponds and evaluate potential variables influencing use of water bodies by lesser scaup (and might therefore limit the growth of the lesser scaup population). The specific objectives of this study were to (1) describe and compare the water quality of natural ponds and roadside borrow pits created during highway construction; and (2) evaluate habitat preferences of lesser scaup broods by comparing water quality, physical features and invertebrate abundance in natural ponds and borrow pits that were used or avoided by brood-rearing lesser scaup. Twenty eight water quality, physical and biotic characteristics of ponds were measured in the field or from water samples collected at 48 water bodies. Waters are weakly alkaline, hard, non-saline, and meso-eutrophic. Natural ponds and artificial borrow pits created during highway construction had statistically significant differences (p