Nearly 53 million Americans feed wild birds. The wild-bird-feeding industry estimates that this amounts to about four billion pounds of seed a year! That’s a lot of time, effort, and money spent to bring birds closer. While birding has become a hobby for many individuals, we need to remember to be good hosts while enjoying the show. At Lyric, we spoke with David Bonter, Director of Citizen Science at the Cornell Lab of Ornithology, about how to keep our feeder birds safe and healthy for our backyard friends during the warm summer months. 

Does birdseed spoil more quickly in the summer?

Yes, it does. Any time you combine food and moisture, you have the potential for mold to develop—the seed will just soak up the moisture from the air. Some molds produce a byproduct called aflatoxin, which is fatal to birds. Though not all molds produce aflatoxin, there’s no way to tell whether the mold on your seed is one that does. We wouldn’t eat moldy leftovers so we shouldn’t give anything like that to the birds either.

How can we prevent mold from developing on bird food?

The key is not to put out lots of feeders packed to the top with food, which will then sit for long periods during the hot, humid days of summer. You need to be sure the food is moving through the feeder pretty quickly to prevent mold from forming. Make sure you keep your stockpile in a cool, dry place. If you find any mold on your seed, in either the feeder or storage container, get rid of it.

Can bird feeders cause sickness in other ways?

We often hear of big outbreaks of salmonellosis—which is any sickness caused by salmonella bacteria. There are thousands of different strains, and it is everywhere in the environment. Humans can get sick from it, too. Among birds, it’s spread through seed or other foods that are contaminated with droppings from a sick bird.

Is there any way to reduce the likelihood of salmonellosis?

We suggest that people move their feeders more often. If you keep them in one place for a long time, the seed hulls can build up, and so do the droppings. You can maintain a safe, clean feeding environment by moving feeders and not allowing waste to concentrate in one area. Wash the feeders if you see any sick birds.

Can suet go bad in warm weather?

The unrendered chunks of raw suet you can sometimes get from a grocery store will become rancid in warm weather. Prepackaged suet cakes can also melt in the heat and harbor mold and bacteria. Some of the prepackaged cakes come in “no-melt” varieties. They’re rendered (cooked down) multiple times so the cakes stay solid at higher temperatures. Placing suet in a shady spot also helps.

How can you tell if a bird is sick, and what should you do if you see a sick bird?

Birds that are not feeling well tend to sit very still, with puffed-up feathers, and they may have partially closed eyes. Generally, human intervention is stressful for birds, especially if they’re already sick. And humans can get salmonella, too, so handling sick birds is not a good idea. It’s also illegal to keep wild birds in captivity in the United States without a special permit. You should move and clean the feeders, but leave the bird alone. Some of them do recover from these illnesses. We’ve found birds with salmonella antibodies in their systems, so we know that they’ve had the sickness before and become well again.

From the Summer 2014 issue of Living Bird magazine. Reprinted with permission for the Cornell Lab of Ornithology.