5/02/2010

Critter of the week: White-throated sparrow

The white-tailed sparrow comes in two models: white-striped and tan-striped. The first model, seen here, has black and white head stripes, whereas the other model has brown and tan head stripes. Technically, this is known as plumage polymorphism — but I only talk that way when I'm trying to be uppity.


Click to enlarge.

Now here is where things get interesting. The white-striped members of this species defend their territory more aggressively than their tan-striped brothers and sisters. On the other hand, the tan-striped individuals take better care of their young. So, if you were a baby white-throated sparrow, which parental style would better ensure your survival?

Don't try answering, because it's a trick question. White-striped individuals almost always mate with tan-striped individuals, and vice versa. So, as a baby sparrow, you always benefit from both parental styles.

White-throated sparrows tend to stay near the ground, but I tricked this one into posing at eye level by placing some sunflowers seeds on a fence post.

For more information on the white-throated sparrow:

- Smithsonian Migratory Bird Center

- Cornell Lab of Ornithology

- Wikipedia

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