Biological Projects

Each September, an average of 23,000 Steller's eiders arrive from their breeding areas on the arctic coasts of Russia and Alaska to molt in Izembek Lagoon. Since 1961, Refuge staff have been capturing and banding Steller’s eiders while they are flightless. After the Alaska breeding segment of the population was listed as "threatened" under the Endangered Species Act in 1997, the banding effort became standardized and a goal was established to capture and band 2,500 eiders each year. Data from this project are used to obtain estimates of survival rates that are considered representative of most of the Pacific population.

	Izembek Lagoon in September. The Steller's eider catch pen.
	Steller's eiders being herded into the catch pen. Note some are re-captured from previous years' efforts.
	A successful round-up of flightless Steller's eiders on Izembek Lagoon.
	Izembek Refuge staff and volunteers banding captured Steller's eiders at Izembek Lagoon

Thousands of geese and other waterfowl stage in Izembek Lagoon and adjacent coastal waters from late August until mid-November. Black brant, Canada geese, and emperor geese feast on the abundant eelgrass, while northern pintails, mallards, and other ducks dine on eelgrass seeds. Additionally, Steller’s eiders, common goldeneyes, and other sea ducks search for the marine invertebrates that live in the eelgrass meadows. Refuge staff conduct age ratio counts on flocks of brant and emperor geese to help gauge the productivity of these populations. Aerial surveys are flown periodically to determine distribution and abundance of migrating and overwintering waterfowl.

The Alaska Peninsula and Unimak Island include some of the highest density brown bear populations in the State of Alaska. Aerial brown bear stream surveys have been conducted along salmon streams in the Joshua Green River watershed and on Unimak Island annually since 1968. These surveys provide a minimum population count and information on productivity in each area. In 2002, an aerial line transect survey was conducted, in cooperation with the Alaska Department of Fish and Game, on Unimak Island and the southern Alaska Peninsula to estimate population size and density. Approximately 169 bears per 1000 km2 are estimated to occur on the southern Alaska Peninsula and 102 bears per 1000 km² on Unimak Island.

There are two distinct groups of tundra swans breeding on the lower Alaska Peninsula. Those nesting in the Pavlof Unit are part of the western North America population and migrate to wintering areas in Washington, Oregon, California, Nevada, and Utah. Swans breeding on Izembek Refuge and Unimak Island, however, form a unique, essentially non-migratory population. During winters with heavy ice cover, these overwintering swans congregate at spring-fed lagoons on Unimak Island. Aerial population surveys are conducted each spring to assess population trends and productivity of the swans.

Overwintering "non-migratory" tundra swans congregate at the ice-free waters of Peterson Lagoon on Unimak Island.

The Southern Alaska Peninsula Caribou Herd occurs on the Alaska Peninsula between Port Moller and Isanotski Strait. Caribou are also present on Unimak Island, the only island in the Aleutian chain to have native caribou. The Refuge attempts to conduct an aerial population survey every winter to ensure that the population size of the herd meets cooperative management objectives. Completing these surveys is always challenging because of highly variable snow cover and harsh winter weather conditions. In cooperation with the Alaska Department of Fish and Game, the Refuge also monitors cow/calf and bull/cow ratios for assessment of herd condition.

Aerial surveys of the Southern Alaska Peninsula Caribou Herd are conducted throughout the year.

Refuge staff conduct one road-based and several off-road breeding bird surveys each June. Habitats encountered during these surveys include crowberry heath tundra, wet sedge meadows, gravel ridges, alder thickets, coastal marshes, mudflats, gravel beaches, and small streams and ponds. More than 40 species of birds have been recorded during the surveys, including rock sandpipers, Lapland longspurs, savannah sparrows, golden-crowned sparrows, and willow ptarmigan.

A golden-crowned sparrow sings in the alders.

Izembek Lagoon includes the largest eelgrass beds in North America. Eelgrass habitats are among the most productive and biologically diverse ecosystems on the planet, providing food, breeding areas, and protective nurseries for waterfowl, fish, shellfish, crabs, and many other animals. During 1963-1983, Dr. Peter McRoy of the University of Alaska-Fairbanks and his graduate students collected data about the eelgrass population, its associated organisms, and the environmental conditions of the eelgrass community at Izembek Lagoon. Recently, Dr. McRoy has transferred the historical data that was collected from field notebooks to an electronic database in preparation for conducting a retrospective analysis of this data. He is also examining the effects of changes in climate and ocean conditions on eelgrass and its associated organisms.

Last updated: July 18, 2008