Experiment in females uncovers male hormonal mechanism
In male songbirds of the temperate zone, the concentration
of sex hormones is rising in spring, which leads to an increase in song
activity during the breeding season. In the tropics, there has been little
evidence so far about such a clear relationship between hormonal action and
behaviour, which is partly due to a lower degree of seasonal changes of the
environment. Researchers of the Max Planck Institute for Ornithology in
Seewiesen have now discovered that in duetting African white-browed sparrow
weavers, the solo song of dominant males is linked to elevated levels of
testosterone.