Volume 1 2013

Vicky Harris
Photo: Narayan Mahon


Green Bay Waterfowl Populations Just Ducky

Aerial and ground waterfowl surveys of Green Bay conducted by the Wisconsin Department of Natural Resources (WDNR) in October yielded surprising results, and Wisconsin Sea Grant’s Vicky Harris was on hand to help.

On Harris’s first survey, team members saw an estimated 48,000 ducks, an unusually high number. Canvasback and redhead ducks were the most common types. Aerial surveyors count the ducks via voice recorder; then someone else listens to the recorder and gets a number estimate. Harris was involved in what’s called “ground-truthing,” using binoculars and spotting scopes to verify counts.

WDNR wardens use the counts to determine “duck-use days” for the bay as part of the effort to get it delisted as an area of concern. The wildlife population target is 2 million duck-use days. Back in the 1970s, the number of duck-use days was less than 1 million. According to Harris, the 2 million goal was first met in the 1990s, but an official duck survey hasn’t been done since 1997-99.

Given that other wildlife population targets haven’t been met, WDNR wardens needed an updated survey to ensure that duck numbers are still strong. (Apparently, they are.) They’re also interested in seeing how declining water levels and changes in food availability have affected duck species in the bay area.

The Aquatic Sciences Center is the administrative home of the
University of Wisconsin Sea Grant Institute & University of Wisconsin Water Resources Institute.

©2011 University of Wisconsin Board of Regents