|A leucistic house sparrow! |
|A female house sparrow, Passer domesticus, with normal coloration.|
European house sparrows are so common in New York City that they are easy to overlook.
But I saw a special one in Cadman Plaza Park in Brooklyn Heights last weekend -- a female with patches of white feathers on her back, sides, and tail. She has a genetic condition called leucism, which prevents the normal deposition of pigment in some of her feathers. (Another form of the condition can cause birds to be pale all over.)
Leucistic birds are pretty rare. The Feeder Watch Project
run by the Cornell Lab of Ornithology, for instance, reported fewer than 1000 leucistic birds among five and a half million observed during one year at feeders across the US and Canada. That's less than one bird in 5500, or about 0.02%.
I hope this one stays in my neighborhood for a while. I'll report back if I see her again.
|Click on the photos to enlarge. |