Males in short supply? Or unreliable? Well, two mommies will do just fine. Laysan albatrosses in Hawaii employ a strategy called reciprocity, whereby unrelated females pair together and take turns raising offspring. On the island of Oahu, where 59% of the albatross population is female, fully 31% of the nests are female-female pairs. And though they raise fewer chicks than male-female pairs, given the shortage of males, fewer chicks are better than none. Plus, because albatross can raise only one chick a year, the females stay together in monogamous couples for years, allowing both females the opportunity to reproduce.
The findings, by University of Hawaii at Manoa zoology doctoral candidate Lindsay Young and coauthors BJ Zaun and EA VanderWerf, are published today in the Royal Society journal Biology Letters, in the paper "Successful same-sex pairing in Laysan albatross."