Salmonella is not the most interesting topic to write or talk about, but it's important to bring it up at least once a year - especially around this time. I was reminded again of the subject one recent morning when I filled the birdfeeders.
With the great abundance of common redpolls and American goldfinches I've had around my place this winter, and going through pounds and pounds of black oil sunflower seeds, the ground below the feeders are thick with discarded and dropped seeds and hulls - a veritable breeding ground for the disease.
According to a Canadian fact sheet I came across on the Internet, Salmonella is a normally occurring bacterium found in the gut of many different species of wild and domestic birds. However, because of limited food sources, concentrations of birds around available food, and inclement winter weather, birds experience stress and thus, are more susceptible to Salmonella infections.
Symptoms of the disease are easy to spot. Afflicted birds act sluggish and display droopy heads, spread wings, puffed out feathers, and labored breathing. They lose their natural fear and often allow people and other animals to approach closely, which of course increases the likelihood of being killed by predators, including domestic cats. As well, birds in such poor physical condition are also vulnerable to dying from exposure.
Individual young and old birds alike are susceptible to the disease, but outbreaks of Salmonella 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 nutritionally deprived birds.
Salmonellosis is not 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. In one particular Canadian case, a mouse that had eaten contaminated birdseed where birds were feeding was found sick and then died. After testing, it was learned that the mouse had contracted the same type of Salmonella bacterium as what the birds had become sick from.
So, what should you do when a sick or dying bird is observed around your wintertime feeders? And how do you reduce the chances, or perhaps prevent a bird from becoming stricken with Salmonella?
First, it's extremely important to insure that your bird feeding stations don't become sources of infection. This can be accomplished by making certain that your birdfeeders are clean and kept clean throughout the year.
Second, be attentive about the condition of your birdseed. Is it damp? Moldy? How, where, and in what do you store your seed? If your birdseed is stored inside the garage or some other out-building that isn't climate controlled, then it's essential that you store your seed in a container that's both weather and mouse-proof. Moreover, providing clean, dry and fresh birdseed is critical to maintaining a healthy environment for your visiting wild birds.
During periods of warm and damp late-winter and early-spring weather, birdseed inside feeders, as well as the residual seeds on the ground, become excellent sources for molds to grow and flourish. Contaminated bird droppings are equally dangerous for other birds and animals that come into contact with it. Therefore, keeping your feeders nice and clean, including the areas surrounding your bird feeders, is necessary to reduce the possibility of Salmonella threatening the health of your birds and other animals.
Removing your feeders from time to time and thoroughly sanitizing them with a dilution of bleach or alcohol is a good practice to adhere to, especially if you feed birds in the winter, have conditions ripe for molds to grow and have observed sick and dying birds. 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 a good idea to take precautions to protect yourself from possible contamination. Wash your hands with anti-bacterial soap and water. Always wear rubber gloves when handling bird feeders for cleaning purposes, or when picking up dead or sick birds and old seed and debris. And be sure to dispose of used gloves, old seed, and dead birds in a proper place to reduce the risk of spreading the disease.
Lastly, some dos and don'ts. Do feed your birds, but do it wisely. If after you've disinfected your bird feeders, make sure they're dry before filling them with seed. Damp environments cause seeds to mold. And keep your birdbaths clean too. Frequently replace dirty water with clean, fresh water.
Don't completely fill your feeders if you don't have to. Feed only as much as the birds will consume in a day. Don't use trays to catch and hold the seed that falls from feeders. The residual seed and bird droppings can harbor the bacterium you're trying to prevent.
Don't continue feeding birds if a Salmonella outbreak occurs. If an outbreak happens, it's time to clean not only your bird feeders, but to remove as much of the birdseed, droppings, and debris as you can from the ground.
As already mentioned, Salmonella is present in the digestive systems of many species of wild and domestic birds. Outbreaks are inevitable during a period of stress, which is usually brought on by harsh winter weather. But you can help slow the spread of such outbreaks by ensuring that you always provide your birds with clean feeders, clean birdseed, and clean birdbaths as you 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.