Always in Season/ Mike Jacobs: Tree sparrows linger long enough to be counted
Tree sparrows on Christmas counts are not unusual in and of themselves. It was the number that was staggering at Icelandic State Park near Cavalier, N.D. Counters in Grand Forks reported only one tree sparrow.
Every Christmas Bird Count brings its own challenges, but the challenge at Icelandic State Park’s count near Cavalier, N.D., was unexpected. Sixty tree sparrows were seen. Tree sparrows on Christmas counts are not unusual in and of themselves. It was the number that was staggering. Counters in Grand Forks reported only one tree sparrow.
The report from Icelandic is my responsibility, since I’m the compiler – the person who brings all the reports together and sends them on to the National Audubon Society, which sponsors these annual counts, and has for more than a century.
The counts are “the best indication we have of long-term trends among wintering birds,” as Dave Lambeth, compiler for the Grand Forks count, pointed out in Brad Dokken’s report on the local count published in the Herald on Friday, Dec. 20.
This is especially true of long-term counts. Grand Forks, for example, is approaching six decades. The count at Icelandic State Park has been done about 30 times, and so we know what to expect. Tree sparrows are expected, but 60 of them in a bunch is surprising and would be just about anywhere. When I asked Lambeth about the possibility of so many tree sparrows so far north, he said he found it difficult to believe.
First, some background on this bird.
The American tree sparrow is a northern nester. Its breeding range is mostly north of the 60th parallel of latitude, the northern border of Manitoba. The entire population is migratory, however. The winter range extends as far north as central Saskatchewan and includes most of North Dakota. There are records for every winter month, but none for nesting birds.
In general, however, tree sparrows aren’t very social birds. Most of the time, they are seen alone, although several might be seen in the same vicinity, but usually not too close to each other. As to flocks, the literature suggests 50 is a big number, though 100 isn’t unheard of – but it is unusual.
Icelandic’s total of 60 birds thus seems possible.
The observers provided excellent reports, noting the relevant field marks, a rusty cap, a rusty blaze behind the eye and a clear grayish breast with a single spot. There are other rusty-headed sparrows and others with spotted breasts (though not with the single spot on a gray background that the trees sparrow presents). The tree sparrow shows off white wing bars, as well, though these occur on other sparrows. The other definitive mark is the two-toned bill, yellow below and dark above.
No other sparrow displays all of these, and no other sparrow that displays even a few of these is apt to be so far north as Icelandic State Park – half a dozen miles south of the Canadian border – in December. The only realistic candidate is house sparrow, an invasive and declining species. Bird guides spend a considerable amount of time distinguishing between these species, because the house sparrow sometimes shows some dirty streaking on the breast, and it has some rust on the head. But the house sparrow is a committed companion of humans. Observers reported that none of the members of the flock stood out, suggesting that the birds were of one species.
The birds were found at the edge of a field where they were foraging among weeds and sunflower heads, which suggests another reason that so many tree sparrows were encountered. Their hardiness is well known; they nest farther north than most other land birds, and they are known for their leisurely southward movement after nesting. As long as food is available, the sparrows are content to tarry. That probably explains their abundance on this year’s Icelandic bird count.
Farmers had trouble bringing in the harvest this year, and many acres of sunflowers were left standing, not only in North Dakota, but in southern Manitoba, as well. A check of the province’s harvest report showed that half the acreage planted to sunflowers last spring had not been harvested by the end of November. Abundant food may have kept tree sparrows farther north than they might usually hang out. It’s impossible to know for sure whether all of the birds in the flock were tree sparrows. Birds do form mixed flocks.
For its unexpected abundance, therefore, the American tree sparrow is bird-of-the-week, just as the snowy owl was last week’s bird on account of its scarcity this year.
The tree sparrow, by the way, is misnamed. It is a denizen of low growth, not of real timber. Not so the snowy owl, of course. There is a true lover of winter weather, and is aptly named.
Jacobs is a retired publisher and editor of the Herald. Reach him at email@example.com.