Northern News Services
The birds apparently died of avian cholera, a bacterial disease that has been affecting the population for at least 10 years.
Although it was one of the largest outbreaks ever observed on Banks Island, the dead birds still represent only a small portion of the total snow goose population, estimated at about 500,000.
Jim Hines, a waterfowl biologist with the Canadian Wildlife Service in Yellowknife, was among a team of biologists doing field work on the island in early July.
"When we got there, it was about a month after it happened," Hines says. "The birds were already dead and many had been scavenged by predators."
He estimates that most of the birds died in mid-June.
The first time Banks Island snow geese were observed dy-ing from avian cholera was in 1991. In the years since, the disease has claimed between 1,000 and 3,000 birds a year. This year's late spring and crowded conditions in breeding areas may have stressed the geese and caused more birds to get sick, Hines says.
Samples from some of the dead birds will be sent to Gary Wobeser, a veterinary disease specialist at the University of Saskatchewan, to confirm that avian cholera was the killer.
Wobeser says avian cholera among snow geese was first reported in the U.S. in 1944.
"We've seen more and more of it as the snow goose population grew larger and larger."
As the geese migrate from their wintering grounds in California and Mexico, they feed on wheat and other cereal crops left in the farmers' fields after harvest. With increased farming, the snow goose population has been rising in the last 30 years, Wobeser says.
On Banks Island, the population of snow geese 40 years ago was near 100,000.