Research Highlights

Nature 454, 671 (7 August 2008) | doi:10.1038/454671a; Published online 6 August 2008

Animal behaviour: Love song

Most male birds sing to attract females, but some species have puzzled ornithologists by continuing to sing long after egg laying.

Valentin Amrhein and his colleagues at the University of Oslo compared blue tits (Cyanistes caeruleus) and great tits (Parus major). Both live in the same places and have similar reproductive behaviour. They differ in that the monogamous great tits often raise second broods; blue tits seldom do.

The team found that great tits carried on singing after egg laying, whereas blue tits reduced singing. They argue that great tits sing both to continue defending their territory and to encourage females to lay a second clutch.