About 1,500 bird carcasses are on the shore of the Great Salt Lake, likely victims of avian cholera, an expert said.

Dead grebes, ducks and gulls are being sent to the U.S. Geological Survey National Wildlife Health Center in Madison, Wis., for examination.

"If I was a betting man, I would bet it was cholera," said Tom Aldrich, a migratory-bird expert at the Utah Division of Wildlife Resources.

Avian cholera, which poisons the blood, spreads when birds are overcrowded and food supplies are short. Death occurs so quickly that birds can fall from the sky or die while eating without showing signs of sickness.

Dead birds have been found along the Great Salt Lake's southern shore. Aldrich said outbreaks have occurred on the lake every few years since the 1990s.

Avian cholera doesn't affect humans, but people shouldn't pick up carcasses or let their dogs chew on them, Aldrich said.

About 1.5 million eared grebes land on the Great Salt Lake during their fall migration. In 2004, about 30,000 of them were killed by the cholera.

"For a long time people thought it was snow geese that carried this around, sort of like Typhoid Mary," said Aldrich, referring to Mary Mallon, a woman who carried typhoid in the early 1900s in New York.

"But we don't get snow geese here," he said.