Kling J W, Stevenson-Hinde J
Anim Behav. 1977 Feb;25(1):215-20. doi: 10.1016/0003-3472(77)90084-7.
Eight autumn-caught female chaffinches were injected with testosterone in their first spring. They were allowed to perch on a particular perch to produce a playback of a normal, male song. Both the course of their song development and the reinforcing effect of the playback song were comparable to that shown by a group of similarly-treated males.
