Female birds nest together
When birds lay more eggs than normal, it is usually a sign that something dramatic is happening to the flock. While investigating that phenomenon among Western seagulls on a California island, two researchers made a startling discovery: most of the apparent egg overproduction was the result of homosexual pairings of female birds, each producing the normal number of eggs. The female pairs—some 10% of the population—produce both sterile eggs and eggs fertilized by a visiting male. "We were absolutely astounded," said George Hunt, 35, a biologist at the University of California at Irvine. "This sort of thing has...