Give Feeders a Spring-cleaning to Keep Birds Healthy
The Department of Natural Resources (DNR) reminds bird-feeding enthusiasts that regularly cleaning and disinfecting the feeders are just as important as filling them - especially in efforts to prevent salmonellosis, a bacterial disease that kills many small birds.
Salmonellosis occurs when a food source is contaminated with fecal matter. Since 1970, when this bacterial disease was first diagnosed in Michigan, die-offs around bird feeders have become more common and have been witnessed in many bird species throughout the world.
According to the DNR, bird watchers have reported finding dead birds around their feeders and, on occasion, having seen "sick-acting" birds. Observable signs range from sudden death to a gradual decline of health over one to three days, accompanied by huddling of the birds, fluffed-up feathers, unsteadiness and shivering.
"We have received several calls from people who are finding dead goldfinches," said Brian Piccolo, a DNR wildlife biologist based in Roscommon. "The best thing you can do is remove and clean your bird feeder."
Piccolo said this bacterial disease is most common in house sparrows, pine siskins, American goldfinches and common redpolls, due to their habit of crowding onto the feeding area and remaining there until the food supply is exhausted - greatly increasing the number of bacteria a bird comes in contact with. It also appears that these four species of birds are inherently more susceptible to the bacteria than other wild birds.
The DNR advises that the most important control method for this bacterial disease is to disinfect all feeders and birdbaths weekly with a 10-percent bleach solution. If the bacterial disease is suspected, bird feed should be removed from the area for two to four weeks to allow birds to disperse; this includes encouraging neighbors to also clean and remove feeders. By allowing the birds to disperse, birds infected with the disease can separate from healthy birds. Seed that is under the feeders and on the ground should also be raked or dug up in order to remove contaminated soil.
Fortunately, salmonellosis is not a cause of significant decline in the population of any wild bird species. This disease is of interest to people feeding birds and the symptoms are sometimes mistakenly thought to be the result of poisoning.
"Feeding wildlife congregates them in a way that is not natural," explained DNR wildlife biologist/pathologist Tom Cooley. "Disease transmission is higher when wildlife is concentrated and in closer contact with each other."
Salmonellosis outbreaks around bird feeders generally subside with the milder weather of spring. During the spring and summer, when people typically do not feed birds, birds will forage individually while remaining in the same area.
Learn more about salmonellosis and other wildlife diseases typically found in Michigan at the DNR website, www.michigan.gov/wildlifediseasemanual.
The Michigan Department of Natural Resources is committed to the conservation, protection, management, use and enjoyment of the state's natural and cultural resources for current and future generations. For more information, go to www.michigan.gov/dnr.