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Avian cholera is killing eared grebes, and likely ducks and gulls, on the Great Salt Lake in what is becoming a familiar event on the important migratory bird flyway.
Prevailing northwesterly winds have blown about 1,500 bird carcasses into windrows along a half-mile stretch of the lake's southern shoreline near Saltair, Tom Aldrich, migratory game bird expert for the Utah Division of Wildlife Resources, said Wednesday.
While the disease doesn't affect humans, people shouldn't pick up the birds or let their dogs chew on them, he said.
Avian cholera has been confirmed in the eared grebes. Gull and duck carcasses have been sent to the U.S. Geological Survey National Wildlife Health Center in Madison, Wis., for analysis.
"If I was a betting man, I would bet it was cholera," Aldrich said.
Introduced from domestic fowl during the 1940s, avian cholera has become the most common infectious disease among wild North American waterfowl but didn't appear in Utah until the late 1990s. In 2004, avian cholera killed about 30,000 eared grebes on the Great Salt Lake.
How avian cholera came to Utah remains a mystery. "For a long time people thought it was snow geese that carried this around, sort of like Typhoid Mary," Aldrich said. "But we don't get snow geese here."
About 1.5 million eared grebes land on the Great Salt Lake each fall during their migration. Aldrich said the cholera outbreaks have always started with the small water birds.
The outbreaks on the lake now occur every couple of years, he said. As fresh water areas on the lake freeze, the birds move to the southern shore to feed on brine shrimp cysts.
Avian cholera is a kind of blood poisoning that spreads quickly when the birds are overcrowded and food supplies are short. Scientists say death occurs so quickly that birds can fall from the sky or die while eating without showing signs of sickness.
* Avian cholera has become the most common infectious disease among wild North American waterfowl, but didn't appear in Utah until the late 1990s.
* It is a kind of blood poisoning that spreads quickly when the birds are overcrowded and food supplies are short.
* Death occurs so quickly that birds can fall from the sky without showing signs of sickness.
* It doesn't affect humans, but people shouldn't pick up the birds or let their dogs chew on them.