2:36 p.m., April 14, 2009----The observed decline in populations of American black ducks has been a topic of great debate among wildlife researchers and managers. Once the most abundant ducks in eastern North America, black ducks have recently declined to as few as 188,000 on traditional wintering grounds.

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University of Delaware graduate student Kurt Anderson -- a self proclaimed “quack addict” and biologist with Ducks Unlimited (DU) in Delaware and New Jersey -- is working with wildlife biologists at DU and several federal and state fish and wildlife agencies to find out why.

“We know a little bit about the fall migration of black ducks thanks to banding efforts and harvest data, but we know even less about the timing of spring migration, their migration routes, and habitat use patterns on stopovers,” says Anderson. Biologists are unclear as to how migration proceeds among ducks from different wintering areas.

“Conditions encountered during spring migration have a lot of influence on the reproductive success of birds,” Anderson notes. “Ducks must acquire sufficient resources (weight) both before and during spring migration to make it to their breeding grounds in good enough condition to reproduce successfully.”

The topic is of so much concern that the 1986 North American Waterfowl Management Plan (NAWMP) called for the establishment of the Black Duck Joint Venture (BDJV) to research black duck ecology, identify limiting factors, and provide management recommendations. The BDJV is one of only two joint ventures assigned to a particular species; most serve a wide geographic region.

Anderson's master's thesis work entails outfitting female black ducks with satellite transmitters to obtain critical information about spring migration. The ducks are trapped, measured and weighed, given federal leg bands for traditional tracking purposes, and are then equipped with the transmitter.

“Mature females, those in their third calendar year or older, and with a sufficient body weight, are outfitted with a harness and solar-powered satellite transmitter, almost like a little backpack,” says Anderson. Hens over 1,000 grams are selected, with the harness material only adding 38 grams. “After second year (ASY) females are selected because of their importance in population dynamics and familiarity with migration routes. Waterfowl are philopatric, meaning they will often return to the same location they were born to reproduce, sometimes even to their same nests.”

During the winter of 2007-2008, Anderson, in conjunction with DU, the U.S. Fish and Wildlife Service, and state fish and wildlife agencies in New Jersey, Ohio and Virginia, outfitted 29 black ducks with satellite transmitters. An additional 31 ducks were released during 2008-2009 in the states listed above and were joined by three from New York and five from Prime Hook National Wildlife Refuge in Delaware.

Anderson hopes to present his preliminary results at the 5th North American Duck Symposium -- the bi-annual “to-do” in the duck world -- in Toronto this August. “Our initial analysis shows some interesting trends,” says Anderson. “Year two is bound to provide more information because more of the transmitters are responding.”

Anderson, a Michigan native, received his bachelor of science degree in fisheries and wildlife from Michigan State University. He came to the Mid-Atlantic region to work with waterfowl before starting school in Delaware, but isn't the only Blue Hen working on this project who spent his graduate years studying black ducks at UD.

Matt DiBona, game bird biologist for the Delaware Division of Fish and Wildlife, studied seasonal food availability for wintering and migrating dabbling ducks in the Hackensack Meadowlands of New Jersey under the tutelage of Anderson's adviser, Jacob Bowman, associate professor of wildlife ecology.

Similarly, Dane Cramer, a UD master's candidate under Chris Williams, assistant professor of wildlife ecology, is determining food resources and estimating habitat carrying capacity for wintering and spring staging black ducks in coastal and bayside New Jersey. Cramer currently works for the New Jersey Division of Fish and Wildlife and helped Anderson with trapping black ducks in the state.

“This project has been a unique collaboration of state, federal, and private partners,” says Anderson. “We hope to offer further insight into the reasons behind the decline and provide habitat recommendations for wildlife managers throughout the black duck's entire range.”

Viewers can follow the black ducks at this DU Web page.

Article by Katy O'Connell