Saturday, January 26, 2013

Snowbird 2.0

American Tree Sparrow: Always at home in the snow.
From Oak Harbor, Ohio, Kenn writes:  When I was a kid, first learning about birds, I read that "snowbird" was the Dark-eyed Junco's nickname.  Juncos are easy to recognize, and for many people in the eastern U.S., they are characteristic birds of winter.  But for me, the real "snowbirds" are American Tree Sparrows.  Strictly winter birds anywhere south of the Arctic, they arrive with cold weather, and they visit Kimberly and me only when the snow flies.  

American Tree Sparrows belong to the genus Spizella, which makes them relatives of familiar birds like Chipping Sparrow and Field Sparrow.  The main difference is that Tree Sparrows have their center of distribution at least a thousand miles farther north.  Indeed, "Tree Sparrow" is a misnomer:  many spend the summer far north of treeline, on the tundra, where the largest willows are only a couple of feet tall.  In winter, flocks range through brushy fields, marshes, and open country.  Trees aren't really important to them at any time of year. 

Range of the American Tree Sparrow. Red represents the summer range; dark blue is the main winter range, while pale blue shows where it is less numerous in winter. The gray area in between shows where the species passes through in migration.

For years I lived in Arizona, where it was a major challenge to find American Tree Sparrows at all.  If we searched hard enough in the northeastern part of the state in winter, we might eventually find a flock of three or four.  Here in northern Ohio, though, we are blessed with an abundance of these beautiful sparrows in winter.  On Christmas Bird Counts, we tally them by the hundreds.  Flocks move ahead of us along the hedgerows, across the weedy fields, making a soft, musical tinkling chorus as they go.

American Tree Sparrow: soft colors, musical callnotes, active flocks in the brushy fields of winter.
Where Kimberly and I live now, in the country north of Oak Harbor, flocks of Tree Sparrows are nearby all winter.  They're half a mile away, in the willows along the canal, along the edge of the woodlot, in the overgrown fields.  But they don't come to our yard except under certain conditions.  We have more than a dozen bird feeders out, and lots of birds visit every day: goldfinches, cardinals, House Finches, Downy Woodpeckers, Blue Jays, and more.  But the American Tree Sparrows don't come to the yard - until it snows. 

Whenever it snows, American Tree Sparrows move in from the surrounding countryside to feed on birdseed in our yard... at least until the snow melts.
Every time it snows, the number of Tree Sparrows in the yard goes from zero to 20 or 25 within a matter of hours.  They'll be all around the house, hopping on every feeder, sitting in the tops of the shrubs outside every window, taking advantage of our generous supply of birdseed.  (It's almost enough to make me look forward to snow!)    

American Tree Sparrow posing outside our window.  Like all of our native North American sparrows, it shows beautiful feather patterns if we take the time to look closely.
One of the most appealing things about these little visitors from the Arctic is that they do, in fact, leave the yard each time the snow melts. It suggests an admirable level of independence.  Other birds stick around the yard for easy pickings, but the Tree Sparrows only drop in briefly, and they will soon head out to wilder pastures again.  In a few months, when spring comes, when other sparrows come back from the deep south, the American Tree Sparrows will fly away, far to the north, to lands farther north than any junco would go, to lands where it might snow even in summer.  Yes, these are snowbirds, all right. 

9 comments:

  1. Isn't it amazing the behavior ecology you can pick up at feeders?

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  2. I love how you describe them as having "an admirable level of independence", Kenn. We usually have a couple of them at our feeders, but I'll have to watch closer to see if I notice the same pattern of them only coming when there's snow on the ground -- interesting! ~Kim

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  3. Nice set of images, Kenn. I am fond of sparrows as a group, especially the Tree Sparrow with its bi-colored bill and rufous coloring. I have only seen them singly here in Indiana. How fun it would be to see them in flocks! Very informative post.

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  4. Dear Mr. K,
    I'm a big fan of your work and I was wondering if you will be attending the CMBO event in May?
    Regards,
    Lori

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  5. Yeh, the ATSP is a favorite winter bird! Always anticipate it at the feeder when we get our first good snow in December.

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  6. Thank you for this post. Gives us a new appreciation of this little bird. Also, we greatly enjoyed the talks that you both gave at Shreve. They were really good. A lot different than what we expected. You each gave a different and unique perspective on the subjects (as you did with this post).
    Bob R

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