Waterbird production in an urban center in Alaska

Abstract

I conducted waterbird brood surveys near Anchorage, Alaska in 1991. I found 519 waterfowl, grebe, and loon broods containing 2840 young representing 17 species in the Anchorage Bowl. Brood density in Anchorage exceeds that of major waterbird rearing areas in the wildlands of Alaska. Forty-six of 51 (90%) waterbodies, including all man-made waterbodies, supported broods. Man-made waterbodies (n = 22) supported 82% of all broods and 85% of all young. All species used man-made waterbodies to a greater extent than natural waterbodies except Pacific Loons (Gavia pacifica) and Bonaparte’s Gulls (Larus Philadelphia). Man-made waterbodies and urbanization were particularly important for Red-necked Grebes (Podiceps grisgena), Canada Geese (Branta canadensis), Mallards (Anas platyrhynchos), American Wigeon (Anas americana), Northern Pintails (Anas acuta), and Greater Scaup (Aythya marila). Man-made waterbodies may have allowed Gadwalls (Anas strepara), Canvasbacks (Aythya valisineria), and Lesser Scaup (Aythya afflnis) to expand their range into Cook Inlet. The primary waterbird species that appear to be adversely affected by urbanization are Common Loons (Gavia immer), Pacific Loons, Horned Grebes (Podiceps auritus), Ring-necked Ducks (Aythya collaris), goldeneyes (Bucephala spp.), and Sandhill Cranes (Grus canadensis). Wetland habitats in Anchorage need to be protected by strict adherence to the Section 404(b)(1) guidelines and standard mitigation sequencing principles of the Clean Water Act, including mandatory compensatory replacement.