Use-it-and-lose-it genitals for birds

Science News, Nov 7, 1998 by Susan Milius

Among songbirds, the males of an unusually well-endowed species don't waste energy lugging around something not likely to be used.

Young males of the bearded tit grow hardly any so-called cloacal protuberance when isolated from females, report Andreas Sax and Herbert Hoi of the Konrad Lorenz Institute for Comparative Ethology in Vienna in the October Auk. When researchers added females, however, the protuberance began to develop. A male's organ size peaked when his mate produced the first egg and then shrank until it was time to start on the next nest. Bearded tits can lay three clutches a season.

In the same issue of Auk, James V. Briskie of the University of Canterbury in Christchurch, New Zealand, observes that reproductive anatomy is finally catching up with other avian research. The field's lag may have originated from Victorian sensibilities, says Briskie. "Perhaps 100 years from now, our century will be judged as overly obsessed by sex, but then, we, too, are the product of our time."