# MN Bluebill Die Off



## Flick (Aug 21, 2002)

Not a good deal for a bird allready in trouble......

Thousands of bluebills dead since Thursday 
Sam Cook 
Duluth News Tribune - 11/06/2007

Dan Markham and Noel Hill of Duluth were setting up to hunt ducks on Lake Winnibigoshish near Deer River on Saturday when they noticed a dead bluebill on shore. A quick walk along the shore turned up another three dozen dead bluebills.

Waterfowl biologists with the Minnesota Department of Natural Resources estimate that as many as 3,000 bluebills, also known as lesser scaup, may have died along the west shore of Lake Winnie.

The die-off began Thursday, said Steve Cordts, DNR waterfowl specialist in Bemidji. Biologists believe the cause is a microscopic trematode, a kind of fluke, present in snails that the bluebills are feeding on.

Cordts thinks the die-off could continue. "We're going to find a lot more dead," he said in a telephone interview Monday.

Cordts and other DNR employees collected about 1,000 dead bluebills from a stretch of shoreline on Friday. In the time it took to collect about 900 of those birds, another 30 to 50 had died in the same stretch.

"This is potentially pretty bad because of this snail," Cordts said. "The trematode is likely brand new to the system. It could be along the whole stretch of the Mississippi River and could get into other lakes and into other species. It's way too early to speculate a lot."

"We were just heartbroken," Markham said. "It's depressing."

The die-off also has affected coots, Cordts said, although most coots have already left Lake Winnie. He didn't know how many bluebills remained on the lake.

The snail that apparently is a host of the trematode is the banded mystery snail, Cordts said. It was first documented on Lake Winnie eight years ago by fisheries biologists.

"It's been concentrated on the west side [of the lake]," he said. "Its numbers have really exploded."

Die-offs of waterfowl due to trematodes have occurred in the spring and fall since about 2002 on the Mississippi River near Winona, Minn., Cordts said, though not in numbers as high as those on Lake Winnie.

DNR officials sent a few ducks to the National Wildlife Health Center in Madison, Wis., on Thursday. An initial inspection turned up the trematode identification in one duck, but DNR officials were waiting Monday for confirmation of that in other samples.

Hunters or others should not eat any duck that appears to be obviously diseased, Cordts said. Hunters should use latex gloves when cleaning their ducks.

Cordts said he doesn't know of any other major waterfowl die-offs due to trematodes other than those near Winona. Controlling the snail that serves as a host would be "almost impossible," he said.


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## deacon (Sep 12, 2003)

This cannot be good for all ducks everywhere!


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## dogdexter1 (Sep 6, 2007)

leave the mallards ALONE!


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## OBSESSED (Nov 23, 2006)

what a shame


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## blhunter3 (May 5, 2007)

should we still hunt them this year or not?


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## Whistler31 (Feb 1, 2007)

Here's a DNR Follow up with a bit more information:

FOR IMMEDIATE RELEASE
Parasite likely cause of scaup, coot deaths at Lake Winnibigoshish (November 6, 2007)

Trematodes, a small intestinal parasite, are believed to have killed about 3,000 waterfowl on Lake Winnibigoshish beginning last week, according to the Minnesota Department of Natural Resources.

These parasites have a complex life history and require two intermediate hosts, such as snails, for the parasites to develop. Waterfowl then consume the infected snails, and the adult trematodes attack the internal organs or blood of the birds. Infected birds appear lethargic and have difficulty diving and flying before eventually dying.

Dead and sick birds were first observed on Oct. 28 on the west shore of the lake. Specimens were shipped to the U.S. Geological Survey's National Wildlife Health Center in Madison, Wis., for examination and confirmation of the parasite. The parasite was confirmed in two birds, but further lab results are pending.

Staff from the Minnesota DNR and U.S. Department of Agriculture's Wildlife Services removed about 1,000 dead scaup from Lake Winnibigoshish on Nov. 3. Wildlife officials estimate that about 3,000 scaup and a few hundred coots have died so far.

"We did some reconnaissance of the entire lake and it appears most of the mortality was concentrated on the west side of the lake, particularly around Rabbit flowage and Raven's point," said Steve Cordts, DNR waterfowl specialist. "We cleaned up a small stretch of shoreline with the highest concentration of dead birds and plan to continue to monitor this area to better estimate the magnitude of the die off or whether other species may be susceptible."

Waterfowl and coot deaths caused by trematodes have been documented on the Upper Mississippi river in southern Minnesota during the past five years. The exotic faucet snail serves as the host for the trematode on that stretch of the river.
"We suspect a different snail (the banded mystery snail) may be serving as a host for the parasite on Lake Winnibigoshish, but further investigation is needed," Cordts said.

Fisheries biologists have documented this snail along the western side of Lake Winnibigoshish for at least eight years, but the full extent of their distribution in the lake, or other lakes, still is unknown. The species is native to eastern North America and has been documented in other lakes in Minnesota.

In previous cases of waterfowl dies-offs caused by trematodes, ducks usually died three to eight days after ingesting a lethal dose of the trematodes. Because these birds appear to be dying within one or two days, the snails may be either extremely abundant or be carrying very high levels of the trematode.

"Since this is the first suspected occurrence related to trematode mortality on the lake, we still have a number of questions to answer about the disease and the snails," Cordts said.

Avian predators and mammalian scavengers, particularly bald eagles and raccoons, have been feeding on the sick and dead birds. There appears to be no documented threat that they are at risk from feeding on carcasses, however.

Avian trematodes are not known to be a health risk to humans, but the DNR continues to recommend that hunters not consume sick waterfowl and use standard precautions, such as wearing rubber gloves and thoroughly washing hands when cleaning waterfowl.


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## snowhunter23 (Mar 2, 2005)

I could care less for the coot lol Save the rest of em tho!!


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## WingedShooter7 (Oct 28, 2005)

dang that sucks! They need to get that under control the Bluebills are suffering as it is.


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