The White-throated Sparrow (Zonotrichia albicollis) is a common species. At one time or another during the year, it is found throughout most of North America. It over-winters here in the Arkansas Ozarks. White-throateds are the only sparrow among our yard birds during the winter.
Habitat: Cornell Labs says, Look for White-throated Sparrows in woods, at forest edges, in the regrowth that follows logging or forest fires, at pond and bog edges, and in copses near treeline. In winter you can find these birds in thickets, overgrown fields, parks, and woodsy suburbs. They readily come to backyards for birdseed. We have several weedy, waste spaces at the edge of our yard. During the fall and early winter, flocks of White-throateds forage in these dried weeds. As winter wears on, we see more of these sparrows under our tube bird feeders and in our tray feeder. While primarily ground feeders, these sparrows also partake of the pseudo-suet (cornmeal, peanut butter and lard) mixture we offer.
According to the Smithsonian Migratory Bird Center these common birds exhibit a characteristic that is rare in birds, they show genetically-based plumage polymorphism. In other words, these sparrows come in two different color forms, or morphs.
During the breeding season, the morphs are most easily distinguished by the colors of their crown stripes. The "white-stripe" morph typically has distinctly contrasting black and white crown stripes and bright yellow lores (the area between the eyes and the base of the bill), while the "tan-stripe" morph has duller black (or dark brown) and tan (or pale brown) stripes and less vivid lores.
...both male and female white-throated sparrows exhibit this polymorphism. Moreover, an individual almost always pairs with another of the opposite color morph for breeding. And despite the fact that images of the white-striped morph are more frequently presented to illustrate the species, the two color morphs actually occur in relatively equal numbers in the population. Most interesting is that behavior differs between color morphs, especially during the breeding season. Both male and female white-stripe birds are more aggressive than tan-stripe birds. In fact, white-striped females will even sing and contribute to territorial defense, whereas tan-striped females do not. In contrast, tan-striped birds of both sexes provide more care to their young than white-striped birds do.
Since the White-throated sparrows I've photographed are in their winter plumage when it's more difficult to distinguish morphs, I'm not really sure if they are white or tan stripe. Perhaps my more experienced birder readers can make that determination.
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