The Minnesota Department of Natural Resources (DNR) has received numerous reports of sick and dead common redpolls and other members of the finch family at bird feeders.
According to Carrol Henderson, supervisor of the DNR Nongame Wildlife Program, similar die-offs are occurring in Quebec and in states ranging from Michigan to New York to Vermont and south through Virginia and North Carolina.
The DNR’s Division of Ecological Services has determined the birds are dying from a bacterial disease called salmonella – Type B. This disease is transmitted by contact between birds, especially where they are concentrated at feeders. It can also be transmitted through their droppings onto birdseed and subsequently ingested by other birds.
“It is extremely important to clean up the areas under the bird feeders, where fallen seed could be contaminated,” Henderson said. Henderson noted the redpolls, pine siskins and other northern finches should be migrating northward this month. The problem will subside as they disperse through their northern woodlands for nesting.
“People can help by removing their finch feeders for a week or so to force the birds to disperse their feeding activities over a larger area,” Henderson said.
The feeders should be cleaned with a solution of two ounces of bleach with one gallon of water, followed by a scrubbing or brushing of the entire surface. Feeders can be put out after about a week, when the redpoll numbers have diminished. According to Henderson, house cats can contract this disease from eating sick songbirds. Veterinarians in Quebec have reported receiving sick cats diagnosed with salmonella B. To protect their pets, people should keep their cats indoors because they can become infected with salmonella B when they kill and eat the sickened birds.