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Two species of phalaropes breed in Arctic regions: the large red phalarope shown here, and the smaller red-necked phalarope. Phalaropes are well-known for their polyandrous breeding systems and reverse sexual dimorphism: females are larger, more colorful, and more aggressive than males, and they compete among themselves for males. After a brief courtship, the female lays a clutch of eggs and the male does all the rest of the work of incubation and caring for the young. In red phalaropes, the females mate with several males in the course of a few weeks before migrating south to their oceanic wintering areas thousands of kilometers away. Since the female's reproductive output is limited by how many males she can mate with, males become a limiting resource and females compete strongly for them. Consequently, females are larger, more colorful, and more aggressive than males. These birds were photographed in a small pond near Barrow, Alaska during the brief Arctic spring; the flying winter-plumage bird was in Monterey Bay, California. |
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