Tuesday, May 6, 2014

Enjoying White-throated Sparrows

Before they're gone again, I must comment on the wonderfully audible presence of white-throated sparrows over the past couple of weeks. They don't stay here long as they move through to preferred breeding territory, but we love hearing and seeing them while they are here. They are often to be found foraging on our front lawn or under our hanging feeders. They're so pretty, and their song is so sweet.

White-throated Sparrow, white-striped morph

White-throated Sparrow, white-striped morph

There are two color morphs of these sparrows. The two photos above show the white-striped morph. Below is the duller, tan-striped morph. They mingle freely, seem to prefer mates of the other morph, and thus occur in equal numbers throughout their range. David Sibley has a nice discussion of their characteristics here. One excerpt: 
Comparing like sexes, White-striped birds are more aggressive, sing more, and spend less time in parental care than Tan-striped. Regardless of sex, White-striped tend to dominate Tan-striped birds in the breeding season. Mated pairs almost always include one of each morph, and because of the chromosome arrangement this pairing always produces equal numbers of Tan-striped and White-striped offspring (Falls and Kopachena, 2010).

White-throated Sparrow, tan-striped morph

I last wrote about white-throated sparrows and their song in April 2011 (when in my enthusiasm I managed to mix up a white-crowned sparrow with the white-throateds, but then set the record straight).

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