Thousands of bluebills dead since Thursday

[nate larson]

Did anyone else see this article???? Does anyone have any thoughts? Do you think this is the reason for the steady decline over the past years?

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.

[ChuckN]

Horrible news!!!!

[tearin' lips]

That is terrible, terrible news. A shock to a species that really can't handle that sort of loss. I am at a loss for words, other than that is really depressing.

[winniewalleye777]

WOW! that is extremely depressing, especially knowing the numbers of bills that come through the western side of the lake.

[trailratedtj]

whats so horrible is that theres nothing that can be done to stop it.

a very said day for the bluebills.

so does this only effect the lesser scaup?

[Scott M]

Another spin-off of non-native species. Banded mystery snails belong in Mississippi drainages further south and definitely not this far north. Other mystery snails (e.g. Japanese, Chinese) are full-out exotics.

There are lots of theories on why bluebills are declining. Check out the September/October 2007 Minnesota Conservation Volunteer to read more on that.

[Sartell Angler]

hoping the scientists will figure it out and remedy the problem before it is too late for the bluebill...seems like one of those things that unless you contain it by a certain point there is no stopping it...kind of like any exotic species I guess

[Scott M]

From a MN DNR News Release:

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.

[Boedigheimer]

nate, it made me sick reading your post.

The tough little buggers migrate up and down the entire continent every year, avoiding hunters for half of it, and living on rough seas most of there lives , and they get killed by a flippin' snail!

[bluebill]

i live for bills this makes me very sad

[Scott M]

Things are going from bad to worse.....

****************************************

Scaup kill on Winni grows to 6,000

by Doug Smith, Star Tribune

The number of dead scaup, or bluebills, on Lake Winnibigoshish in northern Minnesota now might number as many as 6,000 according to the Department of Natural Resources.

More dead birds are expected before the fall migration is over.

Thursday afternoon, a large raft of live scaup were on the lake, said DNR waterfowl biologist Steve Cordts, who feared the birds might also ingest a parasite infesting snails in the lake and die.

Cordts' colleague, Jeff Lawrence, was flying over Winnibigoshish Thursday afternoon and when he returned expected to have a more exact estimation of how many birds have died.

Cordts and the DNR picked up 1,000 dead scaup beginning last Saturday.

He saw many other scaup still alive at the time but unable to fly, or to fly far. "You could boat right up to them," Cordts said. Perhaps 3,000 ducks, mostly scaup, and some coots have died in the past week.

The ducks apparently are dying from trematodes, a tiny 1-millimeter intestinal parasite or fluke that has infected snails in the lake. Scaup -- a duck that dives below water to feed -- eat the snails, then are infected.

"They essentially bleed to death," Cordts said.

The parasite was confirmed in scaup and coots sent to the National Wildlife Health Center in Madison, Wis.

Similar die-offs caused by trematodes have occurred spring and fall since 2002 on the Mississippi River near La Crosse, Wis., killing about 40,000 ducks and coots since then. Die-offs again are occurring there this fall.

Cordts said he's not sure how the trematodes made it to Winnie. They apparently have infected a snail called the banded mystery snail, which was first found on Winnie about eight years ago. They are infecting the faucet snail on the Mississippi.

Officials aren't sure how many ducks might eventually die on Winnie, or what impact, if any, it will have on the scaup population. But Cordts is concerned that the snails and parasites might spread to other Minnesota waters.

Other duck species also could eat the snails and become infected, he said.

There is concern because the continental scaup population has been declining since 1984 and hit an all-time low last year at about 3 million. Hunters annually kill about 300,000. Minnesota hunters killed about 20,000 last year.

Lake Winnibigoshish is a major scaup resting area during migration. "We could have 20,000 scaup show up on Winnie right now," Cordts said. "If that happens, they'd pretty much all be at risk."

Cordts won't collect any more dead ducks. Instead, carcasses will be left to decompose or be eaten by scavengers. The parasite apparently is not a threat to other species, including humans, but Cordts said hunters shouldn't eat sick waterfowl.

[Scott M]

I don't think they are going to be able to get rid of this trematode, what if it sticks around for years?

I know copper sulfate is a popular snail pesticide, but there is no way the DNR or Feds will use it on one of the largest inland bodies of water in MN....

I am hoping to be able to hunt Winni next year for bills, but this is really going to hurt the population. Right now the estimate is 6K birds, by the end of next week, how many will it be?

Consider that Minnesota hunters generally kill 30,000 greater and lesser scaup in a year, and within 2 weeks 10,000 could be dead from a trematode...scary thoughts.

[aland147]

I hunt about 30 minutes directly south of winne, my party has hunted there for over 30 years. We have seen the number of lesser scaup slowly decreasing over the last 10 years. Both local and migratory birds. Im guessing this has had a bigger effect then we probably are aware of over the last couple of years. I agree that this is just more insult to an already badley injured population of ducks in north central MN.