Sunday, August 24, 2008

Botulism confirmed in Midway atoll duck deaths

Wildlife officials have confirmed it is avian botulism that has killed at least a third of the endangered Laysan ducks on Midway Atoll.

The massive die-off appears to have slowed, perhaps with the measures Fish and Wildlife Service personnel have taken, which include flushing freshwater seeps where the birds drink and feed.

Carcasses were shipped to the National Wildlife Health Center in Madison, Wisconsin, where avian botulism was found in all samples. Avian bottulism is naturally found in the ground,and can release large amounts of toxin in water during warm periods and in stagnant water.

The confirmation that the kill was caused by a bird disease that is not transmittable to humans means that wildlife officials can work more easily with the birds. More aggressive searching could turn up more than the last count of 134 dead birds.

“Now that we know we are dealing with avian botulism rather than something like avian influenza that could spread to humans, we can include more people in the search for dead birds without compromising safety,”said Matt Brown, acting manager of the U.S. Fish and Wildlife Service refuge at Midway.

“At the recommendation of the National Wildlife Health Center, we are draining the catchment wetland where most of the deaths have occurred to eliminate toxin production at the site,” he said.

There has been no sign of the disease at Laysan Island, where the larger population of 600 Laysan ducks lives, and since the birds tend not to fly long distances, there is essentially no likelihood that Midway birds will fly the several hundred miles to carry the outbreak to Laysan.

Wildlife officials are now working to figure out how to prevent the botulism outbreak from recurring.

“Over the coming months, we will be discussing several treatment options to preclude or at least minimize future outbreaks of avian botulism,” Brown said. “We will be working with the U.S. Fish and Wildlife Service’s Laysan duck recovery team as well as USGS scientists to ensure the continued survival of this population.”

For more details see the earlier post s at, at, and

For more information on Laysan ducks, see:

© 2008 Jan TenBruggencate

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