Unclean Birdfeeders May Kill Birds

By Phil Cooper, Wildlife Conservation Educator Over the past several weeks, the Idaho Fish and Game has received numerous calls from concerned area residents who have noticed unusually high numbers of dead songbirds in their yards. Several species, including robins, sparrows, house finches, and goldfinches have been affected, but there doesn't appear to be any particular single species affected more than any other. Several factors could be the cause of the mortality. A 1992 study by the Cornell Laboratory of Ornithology concluded that 51 percent of backyard bird deaths were caused by birds striking windows. Predation, predominately by house cats, accounted for 36 percent of backyard bird deaths. Disease caused 11 percent of backyard bird mortalities in the study. The National Wildlife Health Center of the U.S. Geological Survey conducts research on diseases in wildlife. In recent years, they have reported unprecedented songbird mortality events and have identified backyard feeding stations as playing a significant role. Disease is likely the cause of the recent local increase. Recent weather factors including temperature patterns and high precipitation (and humidity) have provided excellent growing conditions for molds and bacteria in our area. There are five diseases commonly associated with bird feeders, each of which can lead to death of individual birds. These include: salmonellosis, trichomoniasis, aspergillosis, avian pox, and mycoplasmosis. The most common of these diseases is avian salmonella, a bacterial infection which infects birds primarily through contaminated food. Avian salmonellosis is a strain that could affect humans and pets. People who feed birds have an obligation to make certain their actions are beneficial to bird populations and to individual birds. A lack of feeder sanitation can have the opposite effectÉdespite the best of intentions. It is extremely important to keep feeders clean to avoid the development of conditions in the feeder that could cause birds to become sick. With the current conditions and apparent recent outbreak of disease in songbirds, Fish and Game is recommending that bird feeders be cleaned once a week for the time being. To clean your bird (seed) feeders, first remove all feed. Make a solution of one part bleach and nine parts water (10 percent bleach solution). While wearing plastic or rubber gloves either soak the feeder in the bleach solution or pour the solution over the feeder. Do not use vinegar instead of bleach, as vinegar does not destroy bacteria, mold, or yeast. Soak the feeder or allow the solution to sit on the feeder for ten minutes. Then scrub the feeder thoroughly with a stiff brush. Rinse thoroughly with additional 10 percent bleach/water solution. Then rinse the feeder very well with plain water. Allow the feeder to dry completely (extremely important!) before reassembling and refilling with seeds. Avoid getting the bleach solution on your clothes or skin. Wear gloves and wash your hands after cleaning your feeders. It is also important to keep the area below and around the feeder clean, as mold, and bacteria can grow on the seed that has fallen on the ground. Birds will continue to feed on this waste seed. Fish and Game recommends moving feeders each time you clean them if at all possible. If your feeders are on permanent structures; rake, shovel or sweep seed waste and bird droppings from the ground under the feeder and discard in your household trash. Birdbaths should be emptied and refilled every day as they can provide habitat for bacteria and parasites that can be harmful to birds. Every two weeks, scrub the birdbath clean with dish detergent, and then rinse with 10 percent bleach/water solution. Rinse carefully with plain water and allow todry before refilling. If you do not think you can maintain a weekly cleaning cycle, Fish and Game recommends that you simply remove your birdfeeders until the fall. Feeding wild birds is a fun, rewarding and educational activity. By taking just a few precautions, we can enjoy the sights and sounds of songbirds that we attract to our backyard and help them in the process.