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GAP Analysis Predicted Distribution Map

Lesser Scaup (Aythya affinis)

Species Code: AYAF

Click to enlarge Range map

= Core Habitat
= Marginal Habitat

Breeding Range Map
The green area shows the predicted habitats for breeding only. The habitats were identified using 1991 satellite imagery, Breeding Bird Atlas (BBA), other datasets and experts throughout the state, as part of the Washington Gap Analysis Project. Habitats used during non-breeding months and migratory rest-stops were not mapped.

Metadata (Data about data or how the map was made)

Click to enlarge distribution map

Map with Breeding Bird Atlas records

Other maps & Information:
  • Breeding Bird Atlas
  • NatureMapping observations
    during breeding season
  • NatureMapping observations
    throughout the year

This species is an uncommon breeder in eastern Washington in freshwater wetlands, possibly nesting in the central Columbia Basin, north to the Okanogan valley and east to Turnbull National Wildlife Refuge. They are a rare and local breeder in lowland ponds of the Puget Trough, with confirmed breeding records from Kent sewage ponds south of Seattle, Everett, and Whidbey Island.

Primarily a breeder in the far north, the Lesser Scaup prefers sedge-dominated marshes in boreal climates such as those found in Alaska and Canada's northern provinces. In fact, it is most abundant on Alaska's Yukon-Kuskokwim Delta. The Washington populations are comparatively small and poorly known. Most of the BBA records are probably based on migrants; those that had formed pairs would be reported as probable breeders. There are two confirmed east side and three confirmed west side breeding records from the BBA period, and there is also earlier evidence of breeding on the east side. The Conner Museum has specimens of three downy young collected in 1949 from Medical Lake, and eight eggs collected in 1950 from West Medical Lake. Thirty definite breeding sites have been listed in eastern Washington occurring in the north from Leahy and Delrio, east through the center of Lincoln County to Medical Lake, Spokane County, and south to northwestern Whitman County, Benge, and Lake Lenore. This list was based on an unreferenced survey so the evidence for breeding is unknown. We limited our model distribution to a few lakes in the vicinity of areas of confirmed BBA records in southwestern Spokane County and northeastern Okanogan County. Like the Ring-necked Duck, the Lesser Scaup is a largely boreal species. It appears to inhabit marginal habitat in scattered lakes and ponds in Washington.

Translated from the Washington Gap Analysis Bird Volume by Uchenna Bright
Text edited by Gussie Litwer
Webpage designed by Dave Lester