When monogamy isn't

Discusses the extent and implications of extra-pair copulation, in which one of an established pair of birds copulates with a 3rd bird. DNA fingerprinting has shown that > one-third of the chicks of buntings and sparrows may be due to EPC. One hypothosis is that a female may occupy a food-rich breeding territory but not pair with the most vigorous male. Therefore EPC with a nearby male may allow the female to choose a high quality site. -R.Land