USFWS
Migratory Bird Management
Alaska Region

Waterfowl

Reports

North Slope Eider Breeding Pair Aerial Survey

A comprehensive aerial waterfowl breeding population survey was initiated in the Arctic Coastal Plain of Alaska in 1986, and has continued annually to the present time. That survey, however, conducted from late June through early July, is phenologically too late for an accurate assessment of eiders, the males of which typically begin to depart the breeding grounds for the post-nuptial molt by about 20 June. Accordingly, in anticipation of the listing of spectacled and Steller’s eiders under the Endangered Species Act, a second, earlier survey was initiated in 1992 primarily to obtain an accurate annual population index and distributional data for these two species. The latter survey has consistently provided useful data for spectacled eiders, king eiders, and several other species of waterfowl, but has proven inadequate in sampling intensity for Steller’s eiders, which are present on the arctic coastal plain in very low densities. Survey transects were 400 meter wide strips, oriented east-west, and systematically placed every 9 kilometers over the wetland habitat. The survey procedures are similar to the North American Waterfowl Breeding Pair Survey. All waterbirds and raptors within 200 meters of each side of the aircraft were recorded by the pilot/observer on the left side and the observer on the right side. Different sets of transects were flown in different years to collect waterfowl locations over a larger portion of the survey area. Population estimates were made by expanding the density of each species observed in the sampled area by the total survey area. Annual population estimates allowed us to calculate trends for each species. The survey has been conducted annually using essentially the same design since it’s inception, though improvements in data collection technology have been added along the way.

Eider Breeding Population Survey Arctic Coastal Plain, Alaska 2006 (pdf)

Click on the links below to see maps of the flightlines and survey area or species distribution.

1998-2001 North Slope Eider Survey Flightlines
Arctic Tern
Brant
Canada Goose
Glaucous Gull
Jaeger species
King Eider
Long-tailed Duck
Northern Pintail
Pacific Loon
Red-throated Loon
Sabine's Gull
Scaup
Spectacled Eider
Tundra Swan
Large Shorebirds
Small Shorebirds
White-fronted Goose
Yellow-billed Loon

Last Updated: September 15, 2008