White-throated Sparrow

Dapper looking little birds.

From the Cornell site - interesting info:

1. The White-throated Sparrow comes in two color forms: white-crowned and tan-crowned. The two forms are genetically determined, and they persist because individuals almost always mate with a bird of the opposite morph. Males of both color types prefer females with white stripes, but both kinds of females prefer tan-striped males. White-striped birds are more aggressive than tan-striped ones, and white-striped females may be able to outcompete their tan-striped sisters for tan-striped males.

2. Although they look nothing alike and aren’t particularly closely related, the White-throated Sparrow and the Dark-eyed Junco occasionally mate and produce hybrids. The resulting offspring look like grayish, dully marked White-throated Sparrows with white outer tail feathers.