Female blue tits sing when in danger: study

Scientists have found for the first time that females of a songbird species, known as the blue tit, sing in the presence of predators.
Until now, the singing behaviour of songbirds had been mainly associated with competitive behaviour and the search for a partner. Moreover, males had long been considered to be the more active singer.
Females were compared to the behaviour of the males and were seen as relatively "lazy" with regard to singing. These assumptions had also been applied to the blue tit.
However, female blue tits, like males, also display a variety of vocal patterns. This suggests that vocalisation is not limited exclusively to courtship or competition.

Herbert Hoi and Katharina Mahr of the University of Veterinary Medicine Vienna have demonstrated for the first time that female blue tits sing in the presence of a predator.
Vocalisation did not serve as an alarm nor was it limited to females.

"We presented the nest of blue tits either with a stuffed sparrow hawk, a bird of prey, or an Aesculapian snake and analysed the reactions mainly of female blue tits," said Hoi.
The team, together with researchers from the University of South Bohemia, for the first time documented vocalisations of female songbirds in danger situations.
Their song strongly resembled that of the males also present in the simulated predation event.

Both sexes, however, reacted only to the threat from the bird of prey and not the snake. The sparrow hawk is considered to be a danger to adults, while the snake is a threat to nestlings that can be more easily driven from the nest.
It is interesting that the blue tits react to the threat by singing. One would assume that singing attracts more attention.
"The animals may be indicating a heightened ability to escape. They show the predator that they have seen it and can flee at any time," Hoi said.
Hoi believes there could be another explanation. The presence of a predator is very stressful. The singing behaviour could therefore simply be an endocrinological response of the body or a "displacement activity."

The researchers were able to exclude the possibility that the females were sending a distress call. In several cases, the male was present during the event, and both would then sing together.
The researchers see the joint singing as a way for the pair to encourage each other and to strengthen the pair bond.