Laura Erickson's For the Birds

(Recording of a Blue Jay)

Every now and then I get a letter from a listener–tangible evidence that people really are listening out there, which is an awfully nice reward for a volunteer radio birdwatcher. Last week I heard from a KAXE listener in Bovey, Minnesota, who sent in this interesting report:

“My mom put moth balls among her new green bean plants to keep a rabbit away. Today, she watched a ‘black’ bird (she has grackles [and] starlings that visit her yard) pick up [a] moth ball in his beak and ‘rub’ it under his wing and on his feathers! Is this unusual? Will the moth balls injure the birds?”

Well, amazingly, this kind of behavior is less unusual than you might think. Birds have a major disadvantage in the natural world because they just can’t go into a drugstore and pick up some insect repellant, no matter how bad the bugs are biting. Like people, birds get attacked by flies, ticks, and mosquitoes, and as if that weren’t enough, a whole host of lice and mites also victimize them. Although birds can’t buy a spray can of deep woods off, they can discourage some of these pests by rubbing the bodies of ants on their skin and feathers. Ants belong to the scientific family Formicidae, which refers to the characteristic formic acid in their bodies. This bitter acid probably serves as a natural insect repellant.

A bird’s response to the acidic taste of ants seems to be instinctive. I raised a baby Blue Jay once, and the first time he encountered an ant, I got to watch this unique behavior first hand. He picked up the ant in his beak, the way he picked up any new object, and ran his tongue back and forth on it–but in less than a second he spat it out and shook his head violently, the way a child does after swallowing a particularly repulsive food item. Then he cocked his head, rubbed his tongue in his beak another time, and picked up the ant again. This time he leaned over to one side, spread the opposite wing, and rubbed the ant on the feathers. The taste of the ant seemed to release this rubbing behavior. By the time he switched sides, the ant body was pretty mangled. He didn’t eat it–he just left it on the table for me to clean up.

At least 200 species of birds have been observed anting like this. Not only do they actively rub ants on their bodies, some species, like the American Crow, engage in what ornithologists call passive anting—they sit on an ant hill with their wings spread on the ground, allowing the ants to crawl through their feathers.

Now a mothball may not be an ant, but don’t tell that to a bird. They’ve been recorded anting with beetles, mealworms, pieces of lemon, orange juice, coffee grinds, vinegar, beer, hot chocolate, soapsuds, and sumac berries. The Tobacco Institute may fool birdbrains into believing that cigarettes are attractive, but real birds know better—they use cigarette and cigar butts to repel disgusting parasites. Mothballs aren’t usually available to backyard birds, but there is a record of a flock of grackles in Milwaukee rubbing mothballs on their bodies, exactly the way the Bovey listener describes. So there’s always something new and unexpected to learn about in the world of birds.

(Recording of a Blue Jay)

This is Laura Erickson, and this program has been “For the Birds.”