Bighorn River waterfowl die-off linked to starvation

A high number dead waterfowl reported on the Bighorn River south of Hardin in February was due to starvation, according to Montana Fish, Wildlife and Parks.

According to a May 5 press release, FWP staff collected mallard, geese and shorebird carcasses along a stretch of the Bighorn River from Afterbay to about three miles downstream of the Bighorn Fishing Access Site following numerous reports of sick and dead waterfowl in the area.

Staff initially suspected the mortality event was related to Highly Pathogenic Avian Influenza, but extensive testing at the department’s Wildlife Heath Lab in Bozeman showed no positive results for the disease.

Additional testing was done by the U.S. Geological Survey’s National Wildlife Health Center in Wisconsin, where specialists confirmed there was no evidence of infectious diseases. Instead, emaciation and starvation were the only ailments consistently found among the tested birds.

According to the press release, FWP said that mid-winter waterfowl surveys done along the Bighorn River showed a higher than average concentration of birds, “which likely led to more competition for the limited food in the area.”

In addition, extreme cold temperatures and high snowfall in the region during early January likely contributed to limited availability of food.