Now and then The under side of the long primary wing feathers usually gets the most attention. Sometimes birds try so hard to reach inaccessible parts of their bodies that they fall over and roll on the ground.
CAPTION: This blue jay has picked up an ant, crushed it and then is rubbing the ant on its feathers. This odd behavior has been observed all over the world with many different species and is called “anting”.( Drawing by B.P.Burtt)At other times, the bird will lie down on an ant hill and let the ants crawl through its feathers. In this case it may be that the ants feed on the vermin they find amongst the feathers.
It is not really certain why birds do this. The most reasonable idea is that this treatment in some way removes parasites that are found in the feathers of all birds.
If an ant is crushed, a small amount of formic acid is released. It is this compound that is responsible for the sting in the bite of the ant. Perhaps the acid repels or kills parasites.
Poet Ogden Nash wrote: “The ant has made his name illustrious. through constant industry, industrious; so what, would you be calm and placid, If you were full of formic acid?”
Other substances have been rubbed on the feathers. Grackles and starlings have used the acidic juice from green walnuts. After pecking a hole in the shell and wetting the bill in the juice, the bill was thrust into the feathers.
Mothballs are sometimes used in a garden to repel rabbits. A grackle once picked up a mothball and rubbed it on the under side of one wing and on the body on that side. After dropping the mothball and preening its feathers, it gave the same treatment to its other side.
Beer, orange juice and vinegar were used by some rather tame song sparrows in one yard where the owner put out different substances to see what the birds would use. Some 40 different substances have been rubbed by birds into their feathers. These include cigarette and cigar butts and even a discarded cigarette that was still smouldering.