thumb|A [[black drongo in a typical anting posture]]

Anting is a maintenance behavior during which birds rub insects, usually ants, on their feathers and skin. A bird may hold a single ant in its beak to rub over the body, or lie in an area of high insect density and wallow as when dust bathing. Ants secrete chemicals like formic acid to aid in their defense against bacteria and parasites. It has been hypothesized that formic acid may help birds avoid similar ailments by acting as a deterrent. Alternatively, anting could make the insects edible by removing the distasteful acid, or possibly supplement the bird's own preen oil. More than 200 species of bird are known to participate in this behaviour. Anting may have a similar function to the mammallian behaviour of self-anointing. The behaviour was 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".

Modes

Active anting

right|thumb|A [[brahminy kite anting at lalbagh Botanical Garden in Bangalore, India]]

Anting most commonly occurs on the ground, with some species preferring tree branches. A bird will seize an ant with the beak and proceed to rub it over the feathers. However, there are some cases where an ant is used more than once but never exceeds three uses. However, there is little evidence that chemicals from ants help to remove or deter other parasites such as feather lice and mites.

Food preparation

The food preparation hypothesis suggests that birds rub the ant in its feathers to remove a substance on the ant. Ants produce formic acid as an anti-predator adaptation. Thus, when an ant feels threatened, as when in the beak of a bird, it will spray formic acid. It is suggested that birds then rub the ants in their feathers to remove the harmful formic acid. The bird will then ingest the ant. This can be seen in European starlings, Sturnus vulgaris.

Sensory self-stimulation

Anting has been compared to human activities such as smoking and other external stimuli that serve no biological purpose and are just for self-stimulation. This hypothesis has been suggested as anting has no obvious function, it is non-adaptive, birds are said to achieve pleasure from anting and anting has characteristics of a habit. However, there is no definitive evidence that sensory self-stimulation is the purpose of anting in birds. There have been several studies that claim to prove this hypothesis while others say the opposite.

Functions in molt

It has been found that passerine birds molt in the summer months. These birds often focus much of the anting on their wings and tails. This is where the largest feathers emerge, and it has been suggested that anting helps stimulate the growth of these feathers during molt. Not all birds that ant do so during molt. European honey-buzzards have been found to gather fresh maple branches on the ground and then spread themselves over it and it has been suggested that this might be a case of tool-use to attract ants for anting.

Similar to anting may be the observed habit some birds show of picking up cigarette butts, sometimes lit, and rubbing themselves with them.

References

  • Anting - Description of the behaviour in birds.