This fall is turning out to be the deadliest yet for
loons, ducks and other birds that encounter a natural
outbreak of a rare form of the nerve toxin botulism in
Dr. Ward Stone, director of the New York Department
of Environmental Conservation Pathology Laboratory in
Delmar, N.Y., which studies the dead birds, said that
over the last two weeks his staff had picked up more than
5,500 birds along the shores of Lake Erie in western New
York, between Buffalo and Dunkirk, including 126 loons,
4,500 long-tailed ducks, geese, grebes, mergansers, scaups
and many types of gulls. He said the birds found were
only a small part of the total number killed. "We're very
concerned," he said. "This is the tip of the iceberg."
Canadian wildlife officials have also found large numbers
of birds on Lake Erie. They have counted more than 1,000
dead loons, including 700 on an 18-mile stretch of beach
at Long Point, Ontario. Loons are of special concern because
their numbers in the region are low.
The birds died after eating fish infected with type
E botulism, officials said.
The botulism outbreak killed thousands of resident birds
in the same area this summer. Those that have died in
recent weeks are migratory waterfowl moving south. It
is the fourth year the bacteria have appeared to kill
birds, and no one knows how many years it might last.
This year, New York wildlife officials, who are gathering
as many carcasses as they can find, are trying a new approach,
hoping to head off the poisoning of eagles, hawks and
other scavengers. The toxin does not pose a threat to
humans, officials say, as long as they do not eat fish
or ducks that appear to be healthy.
This is believed to be the largest outbreak of type
E botulism in the United States, and it is believed to
be caused by an invasion of exotic species. A proliferation
of quagga and zebra mussels, brought from Europe in ocean-going
freighters, has greatly cleaned the water in Lake Erie,
allowing sunlight to penetrate to much greater depths
and increasing the production of weeds. Botulism thrives
in decaying weeds and is apparently ingested by the mussels,
and another exotic species, a fish called the round goby.
Birds die when they eat the gobies or mussels.
The outbreak is expected to end when the lake cools
sometime in the next couple of weeks.