Winter is almost over. It's been a long one. Last year at this time we were enjoying one of the warmest Marches on record. In fact, many of the Northland's wetlands and shallow lakes were ice-free by the end of March 2010. I canoed on the little lake behind my house, Lake Assawa, on March 30, the day after ice-out.
But this winter has been a little different than last winter. While the snow and cold came earlier and seems to be hanging with us later this year, I've enjoyed the winter nonetheless. One of this winter's highlights for me has been observing and feeding the huge influx of evening grosbeaks, common redpolls and pine grosbeaks. Indeed, I never get tired of watching these delightful species visiting my backyard feeding stations.
Sadly, I recently picked up a dead pine grosbeak from the ground near one of my feeders. I wondered why it had perished. And while I cannot be certain, the bacterium Salmonella, which is frequently the reason why birds become sick and die in late winter and early spring, especially around feeders, crossed my mind.
A fact sheet that I have about salmonella states that it is a normally occurring bacterium found in the gut of many different species of wild and domestic birds. However, because of limited food sources and concentrations of birds around available food, which is often exacerbated by bad weather, birds experience stress and, as a consequence, become susceptible to the disease.
Symptoms of the disease are easy to identify. Afflicted birds appear lethargic with droopy heads, spread wings, puffed out feathers, and labored breathing. They lose their natural inclination to flee from danger and often allow peoples' and other animals' close approach, thus increasing their likelihood of being killed by cats and other predators or dying from exposure to the elements.
Birds typically stricken are young and old birds, but outbreaks can occur in entire populations, especially when stressors such as major winter storms and the absence of preferred food sources tax the physiological needs of already nutritionally deprived birds.
Surprisingly, salmonellosis isn't a "birds only" disease. Though rare, there have been cases of people contracting the disease through contact with diseased birds, from cleaning and removing contaminated feeders or seed, and from cats that have become diseased.
So, what do we do when we observe sick and dying birds around our wintertime feeders? Or, more importantly, wish to avoid seeing such birds? First, it's important to take measures to insure that our feeding stations do not become sources of infection. This can be accomplished by making certain that the feeders we use to attract birds are clean or cleaned before putting out.
Secondly, be attentive about the condition of your seed. Is it damp? Moldy? How, where, and in what do you store your seed in? If your seed is stored inside the garage or some other out-building that's subject to temperature and humidity fluctuations, then it's vital that you store your seed in a container that is both weather and mouse-proof. Providing clean, dry, and fresh seed is essential to maintaining a healthy environment for your visiting bird friends.
During periods of warm, damp winter weather, birdseed inside feeders and residual seed on the ground becomes excellent sources for molds to grow and flourish from. Contaminated bird droppings are equally dangerous for visiting birds. Thus, keeping your feeders and areas surrounding your feeders clean is essential.
Removing your feeders from time to time and thoroughly sanitizing them with disinfectant is a fundamental practice to adhere to, especially if you feed birds in the winter or have conditions ripe for molds to grow, and if you have observed sick and dying birds. Use water and a 10 percent bleach solution to kill the bacteria.
After your feeders have been sanitized and residual seed has been picked up from below feeders and properly disposed of, you can also reduce the chances of disease transmission by placing your feeders in new locations. Doing so will alter the concentrations of birds - a vital step in controlling the spread of this deadly disease.
Remember, it's important for you to maintain vigilance. Feeders may need to be cleaned and moved at least once a week until signs of the disease diminish. Additionally, if you don't feed birds in the summertime, remove and clean your feeders and put them away until you're ready to hang them back outside for wintertime feeding.
When performing your important birdfeeder and birdseed cleaning chores, it's wise to take precautions to protect yourself from possible contamination, too. Wash your hands with soap and water and wear rubber gloves when handling feeders for cleaning purposes or when picking up dead or sick birds and old seed. And always dispose of used gloves, old seed, and dead birds in a proper place to reduce the risk of spreading the disease.
As already mentioned, Salmonella is present in the digestive systems of many species of wild and domestic birds. Inevitable outbreaks occur during periods of stress usually brought on by harsh weather. But we can help slow the spread of such outbreaks by ensuring that we always provide clean feeders and clean seed for our feathered friends as we get out and enjoy the great outdoors.
Blane Klemek is the Bemidji area assistant wildlife manager, DNR Division of Fish & Wildlife. He can be reached at firstname.lastname@example.org.