Thursday, November 16, 2006

The one who creeps into holes

We've seen three inches of rain in two days. A few days ago, without mucking my good shoes, I walked through woods that are now flooded with blue-winged teal swimming in them. Such is the dynamic nature of bottomland hardwood forests.

James Bayou rose quickly. It always does after a rain event. As the township's only natural waterway, all the fields drain into it causing a rapid swelling of sediment-laden waters. The flooded bayou has caused all the tiny winter wrens to abandon their preferred habitat, the brushy bayou edge, to forage for food in my constructed brushpiles and feeding "stations." Averaging 4 inches long, the same size as a kinglet, winter wrens (Troglodytes troglodytes) are hardly ever seen flying around. They're most often spotted flitting in and out of holes in logs and running the forest floor between shrubs. They are the only wren out of 59 other wren species to live outside the New World. According to the esteemed Cornell Lab of Ornithology, they expanded their range by crossing the Bering Sea land bridge and now live in Japan, Siberia, Taiwan and North Africa. In England, the winter wren is simply known as a wren since it's the only species who lives there.

The wintering population in southeast Missouri is most likely the population that spends its spring and summer in the high coniferous forests of nearby Appalachia. Professional birders are able to distinguish populations by slight differences in the bird's call, but I'm not a professional. The Appalachian birds may sound very different from the Canadian birds, just as folks from North Carolina sound different from the Quebecois. Like most wrens, the winter wren's song is loud and boisterous, but unlike other species', the song lasts 7 to 10 seconds, 2 to 4 seconds longer than the Carolina and house wrens' song. The customary call during the non-breeding period is a series of high pitch chips. They chip and flit about like juncos, scampering around decomposing stumps and logs in small groups.

Deep in the woods, I've noticed they hang out with swamp sparrows, white-throated sparrows, golden-crowned kinglets and juncos, all of whom rush off to the nearest shrub when you run past them. Even if you can't see them up close, the winter wrens' tails are noticeably shorter, stubbier than the tails of Carolina and house wrens. There are only three other species in the area during the winter, the Carolina, the marsh and the sedge wren, and all three of them are larger birds with longer tails than the winter wren.

I don't know if this year's winter wren population is particularly high for this part of Missouri. Last year's Christmas Bird Count report showed the highest populations were in southeast Missouri, but I don't recall see as many as I'm seeing this year. Once the water recedes from the bayou and they have their buttonbush and privet swamp to live in, the winter wrens will leave the high ground of my backyard for their preferred habitat. I've had a good chance to learn their behavior, so on that cold Christmas Bird Count morning, I'll be able to quickly count them and move on. Meanwhile, I'll scout out a big, rotting log full of interesting hiding spots to add to my burgeoning brush pile in case any of them stick around.

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