Anting (bird activity)

In the behavior called anting, birds rub insects on their feathers, usually ants, which secrete liquids containing chemicals such as formic acid, that can act as an insecticide, miticide, fungicide, bactericide, or to make them edible by removing the distasteful acid. It possibly also supplements the bird's own preen oil. Instead of ants, birds can also use millipedes. Over 250 species of bird have been known to ant.

Function
It has been suggested that anting acts as way of reducing feather parasites such as mites or in controlling fungi or bacteria, although there has been little convincing support for any of the theories. It is possible that the use of certain kinds of ants indicates the importance of the chemicals they release. Some cases of anting involved the use of millipedes or Puss Moth caterpillars, and these too are known to release powerful defensive chemicals.

Another suggested function, based on observation of Blue Jays, is that the bird makes the insects edible, by discharging the harmful acid onto their feathers. The birds were found to show anting behaviour only if the ants had a full acid sac, and with subjects whose acid sacs had been experimentally removed, the behaviour was absent.

Finally, it has also been suggested that anting is related to feather moulting. However, the correlation may also be attributed to the greater activity of ants in summer.

History
This behaviour was first described by Erwin Stresemann in German as einemsen in Ornithologische Monatsberichte XLIII. 138 in 1935. Salim Ali interpreted an observation by his cousin Humayun Abdulali in the 1936 volume of Journal of the Bombay Natural History Society with discussion on Stresemann's paper and the suggestion that the term could be translated into English as "anting".

Related behaviours
Dusting with soil from ant-hills has been considered by some as equivalent to anting.

Some birds like antbirds and flickers not only ant, but also consume the ants as an important part of their diet. Other opportunist ant-eating birds include sparrows, wrens, grouse and starlings.