Developmental Color Changes in the Eyes of New Zealand Gulls
Developmental Color Changes in the Eyes of New Zealand Gulls
As every mother knows, the color of her infant’s eyes undergoes changes, more or less marked, during the first year or two after birth. But these alterations are negligible when compared with the color variations observable in the irides of some young birds. For example, the pretty and often quite tame little Red-billed Gull (in New Zealand the Mackerel Gull), Larua scopulinus, is born with a dark brown, almost black, eye, and yet by the time the immature bird is a year old the iris has changed to nearly pure white. A similar alteration is noticeable in the eyes of the much larger but equally beautiful Southern Black-backed Gull (Larua dominicanus) that ranges over the whole Southern Hemisphere. Both these birds are easily domdsticated and act the part of scavengers and devourers of caterpillars and other insect pests. I have often seen them about the Australasian harbors and fields going about their useful work unafraid of man.
Casey A. Wood
Museum of Vertebrate Zoology, Berkeley, California, December 15, 1923
