SIOUX FALLS, S.D. (KELO) — While residents slept, an estimated 85,200 birds crossed South Dakota Monday night, according to the BirdCast tracking website from The Cornell Lab.
Among the birds traveling through the state are snow geese, which according to the South Dakota Game, Fish and Parks, migrate from January through May.
Migrating snow geese have been spotted in South Dakota over the past two weeks, according to the Snow Goose Migration Report.
But thousands of geese spotted on Lake Byron did not travel beyond the lake. Volunteers were cleaning up dead snow geese from the lake on Monday.
The deaths are “likely a result of avian influenza that is being spread within these geese on Lake Byron,” Nick Harrington of GFP communications said in an email to KELOLAND News.
Since Jan. 1, 2022, South Dakota has had avian flu detection in 188 wild birds, according to the USDA’s avian flu updates.
Spring migration has started and with it, comes the likelihood that some of those migrating birds are carrying avian flu.
By the time spring migration is at its peak, just under 500 million wild birds will have traveled across the state, according to BirdTrack. An estimated 318,100 birds were in flight at 7:40 a.m. Eastern Time on Tuesday, according to BirdTrack. The birds in flight number differs from the traveling across the state because, birds will be in flight but not traveling all the entire distance across the state.
The most recent recorded avian flu in a backyard or commercial poultry flock was on Feb. 11, according to the USDA. A total of 6.1 million birds have been affected with avian flu in the state. That includes 114 affected commercial flocks and 26 affected backyard flocks,
The USDA said state’s first wild bird avian flu case was in a snow goose and was confirmed on March 18, 2022.
Migrating birds may often congregate in large numbers. The dead Lake Byron snow geese stayed in the lake area until around Christmas, local residents said in the March 17 KELOLAND story. Those cleaning up the dead snow geese on Lake Byron said six units had collected about 20,000 dead snow geese.
The flu is spread as infected birds shed it. The virus is their saliva, nasal secretions and feces. Other birds can get it if they contact with those infected birds and secretions. Birds can also get infected through contact with contaminated surfaces, according to the Centers for Disease Control.
The CDC said in May of 2024 that more than 100 different wild bird species around the world can shed avian flu. The United Nations said on March 17, that at least 300 new wild bird species have been affected since 2021.
Wild birds, commercial poultry flocks and backyard flocks are not the only species impacted by avian flu.
South Dakota has seven confirmed cases of avian flu in dairy herds as of March 18. The last confirmed case was on July 31, 2014.
There are 70 documented human cases, none in South Dakota.
This is not the first incident of the discovery of multiple dead snow geese in the state. In November of 2022, a local resident found dozens of dead snow geese near the Missouri River in Yankton. A GFP official said then snow geese were big carriers of avian flu that fall.
Avian flu was also suspected in dead geese and snow geese in December 2022 in the Rapid City area. Dead birds were also found in Murray County, Minnesota, in December 2024.
When clean-up of dead wild birds is needed, Harrington said, the “GFP recommends avoiding handling these carcasses without personal protective gear such as rubber gloves and masks.”
The GFP is “providing a nearby disposal site for these dead geese, which GFP will dispose of once cleanup efforts are complete,” Harrington said in his email to KELOLAND News.
