Scoter populations across North American have undergone dramatic declines during the past 30 years. Declining trends for these species have continued in the Puget Sound since our surveys began in 1993 (see Washington Sea Duck Management Strategies - Draft Report to the Washington Fish and Wildlife Commission).
In order to better understand some of the factors that may be causing these declines, the locations of spring staging, summer nesting, and fall molting grounds were documented, as well as the migratory paths to and from the wintering grounds. During the winters of 2003-2006, WDFW, with funding from the Sea Duck Joint Venture initiated a research project to capture and track the migratory movements of white-winged scoters (Melanitta fusca) and surf scoters (M. perspicillata) wintering on Puget Sound.
Captures were conducted in areas representative of Puget Sound (Southern Puget Sound - Henderson Inlet, Eld Inlet, and Peale Passage; Central Puget Sound - Greater Port Orchard area; and Northern Puget Sound - Penn Cove, Oak Harbor, Kilisut Harbor, and Birch Bay). Mist nets were set up during the pre-dawn hours of each capture day. Each mist net was made up of two 3m by 18m nets, fastened between three poles and supported by floating supports. The floating supports were made buoyant by 4 floats per support, painted to resemble scoters. Each end of the set was anchored to the sea floor. To attract scoters to the set, decoys were placed running roughly parallel to the net, in a way to look like a natural scoter flock. When scoters flew into the net they were immediately and carefully extracted and placed into small animal kennels and transported to a nearby larger boat where all pre-surgical processing took place. All captured birds were aged, sexed, measured, banded with stainless steel bands, and documented. Tissue samples and blood were collected. Suitable scoters were transmitted with satellite platform terminal transmitters. This study utilized the latest procedures used in North American sea duck research for implantation of transmitters.
Utilize satellite platform terminal transmitters (PTTs) to to delineate breeding and molting areas, spring and fall migratory pathways, staging locations, and assess intra and inter-annual site fidelity of surf and white-winged scoters.
Data were obtained from 20 white-winged scoters (13 females, 7 males) and 34 surf scoters (25 females, 9 males) – see table with map links below. The project provided us with a wealth of new information about these high priority sea duck species using the Pacific Flyway.
- Currently working on analysis of surf and white-winged scoter winter inter/intra-year site fidelity, home range, and temporal use from Pacific Flyway wintering populations, and;
- Currently assessing surf scoter and white-winged scoter molt ecology (migration, timing, locations, and home range) from Pacific Flyway wintering populations.
- De La Cruz, S.E.W., J.Y. Takekawa, M.T. Wilson, D.R. Nysewander, J.R. Evenson, D. Esler, W.S. Boyd, and D.H. Ward. 2009. Surf Scoter Spring Migration Routes and Chronology: A Synthesis of Pacific Coast Studies. Canadian Journal of Zoology 87: 1069-1086.
- Lok, E.K., D. Esler, J.Y. Takekawa, S.W. De La Cruz, W.S. Boyd, D.R. Nysewander, J.R. Evenson, D.H. Ward. In Press. Stopover habitats of spring migrating surf scoters in southeast Alaska. Condor.
- Lok, E.K., D. Esler, J.Y. Takekawa, S.W. De La Cruz, W.S. Boyd, D.R. Nysewander, J.R. Evenson, D.H. Ward. Submitted. Spatio-temporal associations between Pacific herring spawn and surf scoter spring migration: evaluating a “silver wave” hypothesis. Marine Ecology Progress Series.
- Takekawa, J. Y., S. W. De La Cruz, M. T. Wilson, E. C. Palm, J. L. Yee, D. R. Nysewander, J. R. Evenson, J. M. Eadie, D. Esler, W. S. Boyd, and D. H. Ward. In Press. Breeding synchrony, sympatry, and nesting areas of Pacific coast surf scoters (Melanitta perspicillata) in the northern boreal forest. Studies in Avian Biology.
- Others in progress
- Joe Evenson
- Dave Nysewander (retired)
- Don Kraege
- Bryan Murphie
- Tom Cyra
- Other WDFW Biologists who participated in Captures: Jennifer Bohanan , Jeff Davis, Greg Falxa, Julie Henning, Kye Iris, Kelly McAllister, Pat Miller, Ruth Milner, Brad Otto, Greg Schirato, Tammy Schmidt, Shannon Sewalt, Julie Stofel, and Robin Woodin