White-throated Sparrows

For today's Throwback Thursday, let's talk about the White-throated Sparrow. These sparrows breed as nearby as New York but spend winters in New Jersey on south. 

Although Dark-eyed Juncos have the "snowbird" nickname, White-throated Sparrows are also commonly seen winter visitors in my area. The Cornell Lab of Ornithology says they'll sometimes breed successfully with their Dark-eyed Junco coworkers despite not being closely related. (These kinds of remarks make me wonder how well we really know how closely related our sparrows are.)

The love lives of White-throated Sparrows have an interesting complication. They come in 2 morphs, 1 with a white stripe on their heads and 1 with a tan stripe there. These morphs are independent of sex; both males and females can be either the white-stripe morph or the tan-stripe morph. (All adults should have white throats.)

Here's where it gets complicated. Males of both morphs are attracted to white-stripe morph females, and females of both morphs are attracted to tan-stripe morph males. This means that most of the time opposite-morphs end up breeding together and thus having offspring of both morphs:

  • As much as possible, tan-striped males get together with white-striped females.
  • If there aren't enough tan-striped males, some white-striped males will get to breed with white-striped females.
  • If there aren't enough white-striped females, some tan-striped females will get to breed with tan-striped males.
  • If everyone else is paired up and there are white-striped males and tan-striped females still around, they'll settle for one another.
  • And if there's still anyone left, I guess it's time to court one of those Dark-eyed Juncos.
Here are (what I believe to be) the 2 morphs.
White-throated Sparrow - Tan-stripe Morph
January 10, 2022 at Duke Island Park
Photo 176183037, (c) jpviolette, some rights reserved (CC BY-NC)

White-throated Sparrow - White-stripe Morph
February 16, 2022 at Duke Farms
Photo 186321936, (c) jpviolette, some rights reserved (CC BY-NC)

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