Sea Duck Joint Venture

Common Eider Satellite Tracking Study
Common Eider Maps

Recent studies indicate the Pacific race of the Common Eider has declined dramatically over the past three decades throughout most of its breeding range in North America. Counts during spring migration at Point Barrow, Alaska suggest that numbers of Common Eiders nesting in northern Alaska and the western Canadian arctic may have declined by >50% from 156,100 in 1976 to 72,600 in 1996. Waterfowl breeding surveys on the Yukon-Kuskokwim Delta indicate an even steeper decline of 90% from 51,000 during 1957-70 to 5,000 during 1996-99. The reasons for the decline are unknown partly due to a lack of information about the Pacific Common Eider including their distribution while they are at-sea during migration, molt and winter. Resource development activities in the arctic such as offshore oil and gas in the Beaufort Sea and mining in central arctic Canada have accelerated in recent years adding urgency to the need for information on key offshore areas for Common Eiders. Hence this study was initiated in 2001 by the US Fish and Wildlife Service and Canadian Wildlife Service as a Sea Duck Joint Venture project to locate the key staging, molting and wintering areas used by the Common Eiders that nest in central arctic Canada.

Satellite transmitters were implanted in 31 Common Eiders captured just prior to nest initiation in mid June, 2001 and 2002 at Nauyak Lake about 130 km southwest of Cambridge Bay, Nunavut. A large mist net 6 m tall and 90 m long was strung across a narrows where a creek from Nauyak Lake entered the ocean. This site was recommended by local residents who knew that in spring eider pairs travel back and forth through the narrows between a nesting colony on the lake and areas of early open water at sea. The eiders avoided the net during the day, but were relatively easy to catch between midnight and 4 am when the wind usually died and the sun dipped behind cliffs making the net less visible.

The transmitters were programmed to send signals to Argos satellites for 6 h every 2 to 5 days. The satellites are able to locate the transmitters using the Doppler shift in the transmitted signal as the satellite passes over the transmitter. The eider locations are then plotted on maps using ArcView software. These maps which are posted here are updated every two weeks to allow anyone interested to track the eiders as they move from their nesting grounds to their molting and wintering areas.

This study was funded by:
Sea Duck Joint Venture
Canadian Wildlife Service
US Fish and Wildlife Service
Polar Continental Shelf Project

For more information about the study please contact:
Lynne Dickson
Canadian Wildlife Service
Room 200, 4999-98 Avenue
Edmonton, Alberta
T6B 2X3