The Nature Writers of Texas

The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Sunday, November 14, 2004

House wrens are common in winter
by Ro Wauer

It seems like every pile of brush and wooded area in all of South Texas can claim its very own house wren. This little, rather nondescript songbird has literally invaded our area this year, probably more so than any year than I can remember. It isn't that it is so obvious, because it is such an elusive and solitary species, but its loud calls and occasional songs are commonplace to anyone paying even the slightest attention. Most evident are its sharp sputtering calls, like metallic chips and harsh scolding, although a partial song, especially during the morning hours, is also possible. Its full song, usually limited to spring and on its summertime breeding grounds, is a rapid, bubbling chatter that rises in pitch, then falls off, and usually is given many times in succession.

Oftentimes, even when it is obvious that one of these little songbirds is close by, it can be difficult to see. It is a skulker that rarely spends much time in the open. Sometimes, with low squeaking or pishing noises that get its attention, it may come into the open. But that lasts only a second or two, and then it is back into the safety of its brushy home area. When a watcher finally gets a decent look, our target wren is small, even more so than our common Carolina wren, grayish-brown with barred back and tail, and with pale underparts. Marvelous coloration for concealment. It differs from the larger and reddish-brown Carolina wren, from the similar-sized Bewick's wren that has a somewhat longer tail and an obvious white eyebrow, and it is larger than the reddish, short-tailed winter wren.

House wrens are winter residents only in South Texas, moving into our area by September, but leaving for their more northern breeding grounds by April; a few northbound migrants may still be moving through until early June. Its breeding grounds lie to the north all across the United States and into the south-central portion of Canada. It does nest in Texas along the Canadian River in the eastern Panhandle and westward to Hartley County, as well as in two Trans-Pecos highland sites: Guadalupe and Davis mountains. Plus, it is one of the few songbirds that readily utilize nest-boxes for nesting.

Perhaps, more than most of our resident wintertime songbirds, the house wren does us a great service by feeding on a wide variety of insect pests. One study suggests that its diet consists of 98 percent insects and only two percent vegetable matter. That 98 percent consists of one-half grasshoppers, crickets, locusts, and beetles and one-half caterpillars, bugs, and spiders. Especially during the nesting season, one study showed that a pair of house wrens that were feeding young during one 65-hour period made 667 visits to the nest. They fed their young 637 pieces of food, consisting of 161 beetle larvae, 141 leafhoppers, 112 young grasshoppers, 56 bugs, 29 crickets, 10 moths, 5 ants, 4 miscellaneous and 81 pieces of unidentifiable. Although wintertime residents are no longer feeding young, they still provide us with an amazing service.

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