Second North American Sea Duck Conference - Patuxent Wildlife ...

SECOND NORTH AMERICAN SEA DUCK CONFERENCE
LATE SPRING STAGING HABITATS OF SURF SCOTERS
ALONG THE PACIFIC COAST
Erika Lok¹, Daniel Esler¹, John Takekawa², Sean Boyd³, Susan Wainwright De La Cruz 2 , Dave
Nysewander 4 , Joe Evenson 4 , David Ward 5 , and Kristina Rothley 6
¹Centre for Wildlife Ecology, Simon Fraser University; BC; eklok@sfu.ca
2 San Francisco Bay Estuary Field Station, U. S. Geological Survey; CA
3 Pacific Wildlife Research Centre, Canadian Wildlife Service; BC
4 Washington Department of Fish and Wildlife; WA
5 Alaska Science Center, U.S. Geological Survey; AK
6 School of Resource and Environmental Management, Simon Fraser University; BC
Although Pacific surf scoters (Melanitta perspicillata) have been the subject of a growing body
of research during winter, little is known about their spring migration ecology. Habitat conditions
during spring migration can affect nutrient reserve levels and subsequent productivity, and changes
in migration habitats have been implicated as important factors affecting broad-scale and long-term
population declines in some waterfowl. An important component of establishing such cross-seasonal
effects is the determination of distributions and habitat requirements at critical stages over the
annual cycle. As part of a collaborative study on the Pacific Coast, we are documenting late spring
distributions of Pacific surf scoters, with a focus on identifying important staging areas and associated
habitat attributes. Important staging areas are being identified using a combination of satellite
telemetry data, conventional VHF radio telemetry, and aerial surveys. Both types of transmitters
have been deployed on surf scoters wintering in Baja California (Mexico), San Francisco Bay (CA),
Puget Sound (WA), and the Strait of Georgia (BC). Preliminary satellite telemetry data have indicated
several areas in southeast Alaska where spring migrating surf scoters congregate, including Felice
Strait and West Behm Canal near Ketchikan, Stephens Passage and Gastineau Channel near Juneau,
and northern Lynn Canal. In addition, conventional VHF telemetry and survey data from this year
show similar patterns in stopover habitat use. The habitat attributes of these sites will be examined
using existing GIS habitat data. The timing and distribution of herring spawn events during the study
years may be a particularly important habitat feature of these staging areas; observations made during
this year indicate that surf scoters feed heavily on this resource when available. Other habitat features
that may be particularly important include the timing and distribution of eulachon spawning events
during the study years, as well as bathymetry, substrate type, and exposure.
38 ANNAPOLIS, MARYLAND, USA NOV. 7-11, 2005