Tap-dancing songbirds love an audience

The courting rituals of at least one species of bird change in relation to who’s watching, research shows.

In a paper published in the journal Science Advances, a team led by neurobiologist Nao Ota from Germany’s Max Planck Institute for Ornithology reveals that for a bird called the blue-capped cordon bleu (Uraeginthus cyanocephalus) the wooing process becomes more elaborate if there’s an audience present.

The birds are monogamous, and are known for engaging courtship behaviour in which both partners sing, stamp their feet and hop about in a fashion that Ota and colleagues describe as “like human tap dancing”.

Courtship behaviour, in any species, is regarded by biologists as essentially private communication, in which the primary receiver of the information conveyed is the actual or prospective partner.

Ota’s team, however, wondered just how accurate that assumption was, and discovered that at least in the case of the little cordon bleus the matter is much more complicated.

The researchers took bonded pairs of birds and placed them variously in environments where they were alone together, in the presence of other members of their species, or in the presence of other species of birds.

They found that the courtship behaviour differed according to the company kept.

For birds left to themselves, courting behaviour sometimes consisted only of singing. In the presence of an audience of peers, however, both male and female birds dramatically escalated the dancing bit of the ritual.

In circumstances where the audience comprises birds from other species, dancing disappeared.

The motivation behind ramping up the dance energy in the presence of other members of the same species is not immediately clear, especially since the loved-up pairs still only had eyes for each other.

Ota and her colleagues, however, suggest that the “courtship displays are likely meant to advertise their current mating status to other cordon-bleus”.

This apparent statement of fidelity, however, may not be as simple as it seems. The display, suggest the researchers, “can also function as an implicit appeal for future extra-pair mating with the audience”.