Jeff "Pitboss" Coats
11-23-2006, 03:20 PM
Experts explore status of sea ducks on bay
Are waterway's woes affecting birds' food supply?
BY LAWRENCE LATANE III
TIMES-DISPATCH STAFF WRITER Nov 19, 2006
Federal biologist Matthew Perry's work with sea ducks has taken him all over the Chesapeake Bay. He's usually in a small boat at high speed while trying to nab the fleeing birds by net.
"The bay's always rough, the boat's always bouncing, and the wind chill is unbelievable," he said.
Yet the work he is doing at Patuxent Wildlife Research Center in Maryland is shedding light on some of the least-understood waterfowl in North America.
The bay beckons several types of sea ducks every fall when the species leave their breeding grounds in Arctic Canada and Alaska and journey to the East Coast. Once there, they gather in the bay's shipping lanes and dive 50 feet or more to the bottom to pry up bent mussels, clams and other bivalves that constitute the bulk of their diet.
Thus Perry's concern. The bay is not the smorgasborg it once was. He wonders if pollution-induced problems that are killing shellfish are affecting the birds.
Rarely seen from land, sea ducks tend to stay far from shore in the bay and its lower tidal rivers. The birds are known mostly to commercial watermen, a growing number of duck hunters who target them and bird-watchers willing to brave midwinter boat trips into the bay.
The sea ducks' remote haunts have even kept them out of sight of federal and state biologists who fly over near-shore waterfowl habitat every January to compile a survey of mallard, canvasback, Canada goose and other more well-known waterfowl in the Atlantic Flyway.
"Sea ducks are not as easily counted," said Gary Costanzo, migratory-game-bird biologist with the Virginia Department of Game and Inland Fisheries. Agencies lack the funds to spend the time in the air necessary to sweep the open waters of the bay and count them, he said.
The sea-duck group contains three types of birds called scoters -- surf, black and white-winged -- and the long-tailed duck, which Perry is most concerned with.
In addition to seeking out deepwater bivalves, scoters and long-tailed ducks feed on mussels and clams found in oyster beds.
Diseases have left the bay with approximately 1 percent of its historic oyster population, raising questions about the future of the sea ducks' food supply. Continued disease problems, along with predation from cow-nosed rays, have confounded efforts to re-establish the bay's oyster population.
"If we restore oysters, we'd restore the hooked mussel, which would bring more ducks to the bay," Perry said. "Wherever there are oysters, there are hooked mussels."
Jeff Coats is a sea-duck hunting guide based on Maryland's Eastern Shore. He guides hunters six days a week during the 107-day Maryland sea-duck season from Oct. 2 to Jan. 27.
He says he has observed no decline in the numbers of scoters and oldsquaws since he went into business in 1999, but he agrees that the birds could be affected by changes in food supply.
"I can see that becoming an issue," he said. "How does the lack of protein affect their health and reproduction?"
University of Maryland graduate students working with Perry are addressing such questions. David Kidwell is examining the link between scoters, oysters and bent mussels. Alicia Berlin is studying captive scoters in hopes of learning about their food requirements and feeding habits, Perry said.
On a bay with a long history of market hunting and sport hunting, the availability of food appears to play a defining role in how many ducks, geese and swans the bay attracts, Perry said.
He points to the canvasback and redhead ducks as a parallel. Before water pollution killed most of the bay's underwater grass beds in the 1950s and 1960s, as many as 1 million canvasbacks and redheads migrated to the bay. Now, with bay-grass acreage only a fraction of earlier levels, the number of canvasbacks found on the bay is about 50,000. Redhead numbers have dropped to a couple of thousand.
As for sea ducks, no one knows how many winter on the estuary. Perry estimates there might be 50,000 surf scoters, as many as 20,000 black scoters and probably 50,000 long-tailed ducks.
A biologist who flew a series of parallel flights up and down the length of the bay in 1994 in a search for sea ducks estimated from his findings that the number is more than 400,000.
Whatever the figure, Perry says, no one has tried to count sea ducks consistently enough for a long enough period to tell what's going on.
"We don't have enough data to recognize trends," he said.
Contact staff writer Lawrence Latané III at llatane@timesdispatch.com or (804) 333-3461.
Are waterway's woes affecting birds' food supply?
BY LAWRENCE LATANE III
TIMES-DISPATCH STAFF WRITER Nov 19, 2006
Federal biologist Matthew Perry's work with sea ducks has taken him all over the Chesapeake Bay. He's usually in a small boat at high speed while trying to nab the fleeing birds by net.
"The bay's always rough, the boat's always bouncing, and the wind chill is unbelievable," he said.
Yet the work he is doing at Patuxent Wildlife Research Center in Maryland is shedding light on some of the least-understood waterfowl in North America.
The bay beckons several types of sea ducks every fall when the species leave their breeding grounds in Arctic Canada and Alaska and journey to the East Coast. Once there, they gather in the bay's shipping lanes and dive 50 feet or more to the bottom to pry up bent mussels, clams and other bivalves that constitute the bulk of their diet.
Thus Perry's concern. The bay is not the smorgasborg it once was. He wonders if pollution-induced problems that are killing shellfish are affecting the birds.
Rarely seen from land, sea ducks tend to stay far from shore in the bay and its lower tidal rivers. The birds are known mostly to commercial watermen, a growing number of duck hunters who target them and bird-watchers willing to brave midwinter boat trips into the bay.
The sea ducks' remote haunts have even kept them out of sight of federal and state biologists who fly over near-shore waterfowl habitat every January to compile a survey of mallard, canvasback, Canada goose and other more well-known waterfowl in the Atlantic Flyway.
"Sea ducks are not as easily counted," said Gary Costanzo, migratory-game-bird biologist with the Virginia Department of Game and Inland Fisheries. Agencies lack the funds to spend the time in the air necessary to sweep the open waters of the bay and count them, he said.
The sea-duck group contains three types of birds called scoters -- surf, black and white-winged -- and the long-tailed duck, which Perry is most concerned with.
In addition to seeking out deepwater bivalves, scoters and long-tailed ducks feed on mussels and clams found in oyster beds.
Diseases have left the bay with approximately 1 percent of its historic oyster population, raising questions about the future of the sea ducks' food supply. Continued disease problems, along with predation from cow-nosed rays, have confounded efforts to re-establish the bay's oyster population.
"If we restore oysters, we'd restore the hooked mussel, which would bring more ducks to the bay," Perry said. "Wherever there are oysters, there are hooked mussels."
Jeff Coats is a sea-duck hunting guide based on Maryland's Eastern Shore. He guides hunters six days a week during the 107-day Maryland sea-duck season from Oct. 2 to Jan. 27.
He says he has observed no decline in the numbers of scoters and oldsquaws since he went into business in 1999, but he agrees that the birds could be affected by changes in food supply.
"I can see that becoming an issue," he said. "How does the lack of protein affect their health and reproduction?"
University of Maryland graduate students working with Perry are addressing such questions. David Kidwell is examining the link between scoters, oysters and bent mussels. Alicia Berlin is studying captive scoters in hopes of learning about their food requirements and feeding habits, Perry said.
On a bay with a long history of market hunting and sport hunting, the availability of food appears to play a defining role in how many ducks, geese and swans the bay attracts, Perry said.
He points to the canvasback and redhead ducks as a parallel. Before water pollution killed most of the bay's underwater grass beds in the 1950s and 1960s, as many as 1 million canvasbacks and redheads migrated to the bay. Now, with bay-grass acreage only a fraction of earlier levels, the number of canvasbacks found on the bay is about 50,000. Redhead numbers have dropped to a couple of thousand.
As for sea ducks, no one knows how many winter on the estuary. Perry estimates there might be 50,000 surf scoters, as many as 20,000 black scoters and probably 50,000 long-tailed ducks.
A biologist who flew a series of parallel flights up and down the length of the bay in 1994 in a search for sea ducks estimated from his findings that the number is more than 400,000.
Whatever the figure, Perry says, no one has tried to count sea ducks consistently enough for a long enough period to tell what's going on.
"We don't have enough data to recognize trends," he said.
Contact staff writer Lawrence Latané III at llatane@timesdispatch.com or (804) 333-3461.