The impact of hunting mortality on scoter populations in Washington

Don Kraege, Washington Department of Fish and Wildlife

$30,000

Scoter (Melanitta spp.) numbers have declined significantly in Washington waters over the last 25 years.  In 2003, The Washington Department of Fish and Wildlife (WDFW) initiated studies to better understand the distribution and movements of White-winged and Surf Scoters wintering in Washington marine environments.  These studies are designed to compliment other scoter research projects, including similar demographic studies in Baja California, Mexico, San Francisco Bay, and the Strait of Georgia in British Columbia; foraging and prey studies conducted by the University of Wyoming; and genetic analysis conducted by USGS and the Canadian Wildlife Service. 

Results of these combined projects are providing a better understanding of scoter biology and indicate that a combination of factors is likely contributing to the species’ declines.  Preliminary information indicates that at least a segment of the scoter population shows considerable site fidelity, typically returning daily and annually to the same locations. This finding is of significant interest in Washington because hunting pressure on scoters may be higher in Washington compared to other areas, and we do not have a good understanding of how hunting might or might not be contributing to the overall decline.

Beginning in 1998-99, with encouragement and approval from the hunting community, WDFW reduced the daily bag limit on sea ducks to 4 scoters, 1 harlequin and 4 long-tailed ducks per day.  In 2004-05 WDFW instituted a mandatory report card requiring hunters to record their total take and the counties from which the birds were harvested.  For the 2004/2005 hunting season, a very large number of birds was harvested from Island County.  Within Island County, we suspect the majority of these birds were harvested in and around the Oak Harbor/Penn Cover area of Whidbey Island where historically scoter numbers have been very high in winter.  WDFW has a good working relationship with some of the hunters who traditionally hunt Penn Cove and with many of the residents around the Cove.  Both WDFW and hunters are dedicated to maintaining viable scoter populations and need to know the long-term hunting impacts on scoter populations that winter in Island County.

Using boat based and aerial surveys to count scoter numbers and record flock locations, we will be able to refine our understanding of scoter use in and around the Penn Cove/Oak Harbor. Additionally, more data on movement of marked male scoters is needed to evaluate their movement /site fidelity during winter.  Thus, we propose to increase our aerial surveillance in 2006/2007 in order to increase our sample size for transmitting birds.  These data will augment data collected since 2003 and increase the power and validity of the statistical analyses of scoter movements and site fidelity. 

Data collected will be combined with hunter harvest data, US Fish and Wildlife Service band return data, and other data on Scoter movement and site fidelity as well as Scoter population viability analysis to estimate impact of hunting on scoter numbers in North Puget Sound. Results will be shared with the Washington Fish and Wildlife Commission, which sets hunting seasons in Washington State.