SCOTT SHALAWAY Backyard bird action bugs readers

Every summer about this time I hear from readers about birds behaving strangely. A common situation involves moth balls near the garden.
The letter writers had circled their gardens with moth balls to discourage rabbits from eating the beans and were surprised to find the moth balls scattered a few days later. They wondered if rabbits were responsible.
Later they observed several blue jays or grackles preening themselves with the moth balls! They had broken the moth balls into small pieces, held the pieces in their beaks, and raked them through their feathers. Some even seemed to be pressing the bits of moth balls against the skin.
"What are these birds doing?" everyone asked.
This odd grooming behavior is a variation of "anting" -- an instinctive behavior in which birds appear to use ants to treat their feathers and/or skin. More than 200 species of birds have been observed anting, so it's not unusual. If you have an ant hill in your back yard, watch carefully when birds seem attracted to it. Anting occurs most commonly in midsummer and can be passive or active.
In passive anting, practiced by crows, birds spread their wings, ruffle their feathers and sit on an ant hill. Ants then crawl through the feathers and onto the skin, as they might descend upon any intruder. The ants then presumably do something that relieves the irritation caused by ectoparasites or fungi.
An active anter, on the other hand, grabs one or more ants in its bill and rubs the ants over its skin and feathers. Orioles, grackles and starlings are examples of active anters.
Anting with moth balls is active, and moth balls are just one of many substitutes birds use. Others include bits of fresh lemon, cigarette butts and sumac berries. Most of these substitutes are acidic just like formic acid, a fluid found in ants.
History of anting
John James Audubon reported the first account of anting in 1831. He observed wild turkeys rolling on an ant hill, "to clean their growing feathers of the loose scales and prevent ticks and other vermin from attacking them, these insects being unable to bear the odor of the earth in which ants have been."
In 1876 ornithologist (one who studies the zoology of birds) Abbott Frazar described how his pet crow stood on an ant hill and let the ants crawl over it to "carry away the troublesome vermin."
More recent observations and experiments offer additional insight into anting. Captive starlings, for example, instinctively begin to ant 37 days after hatching. Jungle mynas have been observed actively anting with millipedes, whose potent body fluids could be smelled by human observers 15 feet away. Whether the fluid was toxic or merely repellent is unclear. And when presented with boiled, acid-free ants, starlings only used the ant one time. But they used dead, acid-laden ants several times.
And in a study that compared mite survival on birds that recently anted with those that hadn't, mite mortality was much higher on recently anted birds.
Still a mystery
However, exactly how anting benefits birds remains uncertain and subject to debate among ornithologists. Some suggest that live ants kill or somehow repel ectoparasites such as lice and mites. Others contend that the formic acid squeezed from the bodies of ants relieves the itching caused by ectoparasites, fungi and bacteria. Anting occurs most often under conditions of high humidity, thus supporting the notion that it is related to fighting fungal infections. Still, others argue that ant secretions have antibiotic value for fighting bacteria or fungi. A final explanation is that "ant juices" relieve the irritation associated with late summer feather growth and molt.
Whatever the reason, many birds ant, so watch for this fascinating behavior among your backyard visitors the rest of the summer.
sshalaway@aol.com