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, or
bactericide. 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.
History
This behaviour was first described by
Erwin Stresemann in
German as
einemsen in
Ornithologische Monatsberichte XLIII. 138 in 1935. The
Journal of the Bombay Natural History Society XXXVIII described it in
English in the following year and translated the term as "anting".
Variations
Some birds, including
starlings,
babblers,
tanagers,
blue jays, and
weavers, ant actively; that is, they pick up ants with their beak and rub them over their feathers. There are also passive anters, who simply lie over anthills, such as the
Eurasian Jay,
crows and
waxbills.
Some birds have been seen dusting themselves with soil from ant-hills and this has been considered by some as equivalent to anting.
Function
It has been suggested that anting acts as way of reducing feather parasites such as mites or in controlling fungi or bacteria, however there has been no convincing support for any of the theories. The choice of ants used however indicates that the chemicals that they release are in some way important. Some cases of
anting involved the use of
millipedes and these too are known to release powerful defensive chemicals.
Some suggestions have been that anting may be related to feather moulting however this correlation may also be attributed to greater activity of ants in summer.
References