Anting is a self-anointing behavior during which birds rub insects, usually ants, on their feathers and skin. The bird may pick up the insects in their bill and rub them on the body, or the bird may lie in an area of high density of the insects and perform dust bathing-like movements. The insects secrete liquids containing chemicals such as formic acid, which can act as an insecticide, miticide, fungicide, or bactericide. Alternatively, anting could make the insects edible by removing the distasteful acid, or, possibly supplement the bird's own preen oil. Instead of ants, birds can also use millipedes. More than 200 species of bird are known to ant. In addition, other animals such as squirrels and pangolins may exhibit anting-type behavior. Stoats are known to roll around in moss in a similar way.
Anting (bird activity) Wikipedia
It has been suggested that anting is a way of reducing feather-parasites such as mites, or controlling fungi or bacteria, although there has been little convincing support for any of those 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 (Cerura vinula) caterpillars, and these, too, are known to release powerful defensive chemicals.
Another suggestion, based on observation of blue jays, is that the bird makes the insects edible by discharging the harmful acid onto its feathers. 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.
It has also been suggested that anting is related to moulting. Correlation with moulting, however, may be attributable to the greater activity of ants in summer.
This behaviour was first described by Erwin Stresemann in German as Einemsen in the German ornithology journal Ornithologische Monatsberichte (Volume XLIII, p. 138) in 1935. Indian ornithologist Salim Ali interpreted an observation by his cousin Humayun Abdulali in the 1936 volume of Journal of the Bombay Natural History Society and included a reference to the Stresemann's paper suggesting that the German term could be translated into English as "anting".
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.
Similar to anting may be the observed habit some birds show of picking up cigarette butts, sometimes lit, and rubbing themselves with them.