Black Ducks Attract a Following
(Published by The Quoddy Tides, June 8, 2001)
Now that winter is behind us, the waterfowl drawn to Cobscook Bay's productive waters have shifted about. After spending the winter months in protected areas of the bay, many ducks have left for the summer to breed and rear young in Canadian or inland waters. Others arrived earlier this spring in time for breeding season here.
Black ducks in particular have attracted a lot of attention from researchers and wildlife managers in Cobscook waters and nearby wetlands.
Tom Schaeffer, regional wildlife biologist for the Maine Department of Inland Fisheries and Wildlife, is responsible for monitoring waterfowl populations and setting priorities for habitat protection and management in Downeast coastal waters.
"The very irregular shoreline, good nutrient flow in the bay, and highly productive intertidal habitat makes Cobscook a very attractive area for waterfowl throughout the year," says Schaeffer.
In winter, when many other areas are inaccessible to waterfowl, the strong tides and turnover in the water typically allows for less ice build up across the bay, so wintering black ducks can usually find open water to feed and rest. During the spring and summer months, extensive inland wetlands provide high quality habitats for nesting and raising young. In late summer and fall, migrating ducks return to open waters of the bay.
In the 1970's black ducks were at an all time high. But in the 1980's, numbers began declining sharply. Overhunting and habitat loss across their range, from northern Canada to the northern half of Florida, and west as far as eastern Iowa, have been touted as the primary reasons for the decline in black duck populations.
"Although a whole host of waterfowl species are drawn to the bay, we have been concerned about the status and trends of black duck numbers for the last fifteen years," states Schaeffer. "Strict hunting restrictions put in place, first in the United States and then in Canada, helped bring the numbers back up by the late 1980's and 1990's."
"As a result of the North American Waterfowl Plan of 1986, new emphasis was placed on wintering habitat, when previous research and protection efforts had focused on nesting habitat. The Cobscook Bay area quickly rose to the top of the list as an important area for waterfowl protection along the Atlantic Flyway, with special focus on black ducks because of their declining numbers," says Schaeffer.
While numbers of black ducks and other waterfowl fluctuate from year to year, Cobscook Bay has shown consistently high numbers.
"It used to be bay systems in southern Maine had a higher percentage of overwintering black ducks, but now, on average, a quarter of the state's wintering black duck population is found in Cobscook Bay," Schaeffer says. "It isn't just that Cobscook has a highly productive system, but that the quality of these other systems has declined, particularly in regards to habitat loss."
Roland LaVallee, of Robbinston, has been hunting waterfowl around Cobscook Bay since 1979. LaVallee has observed the fluctuations in the population over the years, but noticed a dramatic increase in black ducks last year out on the bay and on freshwater lakes. With so much time spent outdoors in waterfowl habitat, he is familiar with the habits of black ducks.
"In the winter months, they follow the tide in, and go along the edge of shore feeding on invertebrates in the rockweed. Once their belly is full, they go out and sun themselves, " LaVallee says.
Favorite foods of wintering black ducks include blue mussels, soft-shelled clams, periwinkles, worms, and other invertebrates. They are often seen foraging in mudflats as the tide recedes.
"At the end of February, you start to notice the black ducks change their patterns. As soon as ice out occurs, they leave the salt water and move inland," comments LaVallee. "Sometimes you'll find black ducks nesting in small brooks that have been dammed, and later in the summer they'll take their young out to the saltwater to feed."
Inland, ducklings feed mostly on insect larvae, and add the seeds of wetland plants to their diet when they are about one month old.
Black ducks are known to be more sensitive to disturbance than other waterfowl species. For example, during nesting season females will often abandon a nest when disturbed. Their wariness also keeps hunters on their toes as LaVallee affirms.
"Black ducks are real smart, about the smartest of all the ducks. When out hunting, you have to be very, very still, and not move at all. Black ducks like to have a scout out when they feed. If you're blind is messed up, or showing color, they'll notice it and take off."
Even though black duck populations appear to be stabilizing in Cobscook Bay, there is great concern nationally about their declining number. Hunting restrictions are still in place and attention is increasingly focused on habitat protection. Recent acquisitions by the state and partnerships with landowners have emphasized wetland habitats along the shoreline, where productive intertidal areas and salt marshes attract an abundance of waterfowl species. Straight Bay is an important area of Cobscook Bay, and the northern fringe along Ox Cove appears to have good quality habitat for wintering black ducks, as does Bellier Cove in Dennys Bay.
"Our general concerns now are how much is the shoreline going to change and develop - not to say that change shouldn't happen, but can these changes be made without compromising the health of the bay?" asks Schaeffer. "Loss of habitat, rockweed harvesting, the potential impacts of an oil spill, these are all concerns when considering management of black ducks and other waterfowl here."
At Moosehorn Wildlife Refuge, a study comparing current waterfowl use in the refuge impoundments with information gathered in the mid-1980's will begin this summer. These wetlands provide summer habitat for black ducks that winter on the bay.
For now, trends show a positive future for black ducks in Maine. With continued habitat protection, monitoring, and research, a healthy black duck population can be maintained in Cobscook Bay.
This column was prepared by Cheryl Daigle. Cobscook Soundings was a monthly column produced by the Maine Chapter of The Nature Conservancy. Its purpose was to share what is known about the workings of the Cobscook Bay marine environment, so that all who make decisions about the use or care of the bay have the best available information.
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