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Birding Column: House Wrens' Twice-a-Minute Feeding Frenzy |
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Mathew Tekulsky The Birdman of Bel Air |
| May 25, 2004 |
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After the spring rains Sullivan Canyon, which lies behind my house in Bel Air, California, is a vernal paradise. Everything turns green, and the trail turns into a stream. And the house wrens start to sing. They are ready to nest and raise a family. The song of the house wren (Troglodytes aedon) is intoxicatingly beautiful, more like a long, trilling, high-pitched warble than an actual song. I could sit there in my beloved canyon and listen to this music all day long. But the house wren has other things on his mind. It's busy searching out suitable nesting cavities in the trees, and it's busy communicating with his mate. Every now and then it takes time out to perch briefly on a branch, but most of the time, it is in constant motion. The first pair of house wrens that I saw were checking out a possible nest site in a hole in a limb in a California sycamore tree that was at about a 45 degree angle to the ground, with the cavity situated on the side of the limb. For some reason, this hole was never used but further upstream, a nesting cavity, which a wrentit (Chamaea fasciata) had used the previous summer to raise its young, became the perfect site for a pair of house wrens to raise their brood. I discovered this nesting activity well into the feeding period, and for a couple of days, I was able to watch the male and female house wrens make countless trips to and from the nest, bringing butterflies and all types of insects back to their rapidly growing young. The wrens took very little note of me, in spite of the fact that I was about 14 feet (4.3 meters) away and clicking my camera all the time. They always gave me a little look on their way out of the nest, however, just to be sure that everything was OK. A couple of days later, I came back to the nest site, and not a house wren could be seen. Oh, I heard them all right, flitting to and fro among the trees throughout the canyon—but this nest was deserted. That's how fast it happens. Nature is swift, and she leaves nothing in her wake. Sullivan Canyon In 1921 Amelia Allen listed the following items of food that were fed to a brood of eight house wren nestlings during the period of one hour: "5 ladybugs, 4 crane-flies, 5 large and 4 small beetles, 2 wireflies, 1 lacewing, 1 leafhopper, 5 crickets, 1 grasshopper, 1 butterfly, 1 moth, 1 milliped, 1 grub, and 1 unknown; there were 33 feedings, with an average interval between feedings of 14 minutes and 32.7 seconds for each nestling." And in 1917 Clara Bayliss reported that a male house wren fed its 12-day-old chicks 1,217 times between 4:15 a.m. and 8:00 p.m., and 111 times between 9:15 a.m. and 10:15 a.m.—or about once every 30 seconds! This is similar to what I observed at my house wren nest in Sullivan Canyon. With both parents foraging, the visits to the nest by one or the other occurred about twice each minute. Incredible production. I don't know how they found so many grasshoppers, beetles, caterpillars, crickets, and spiders so quickly. But since virtually the entire diet of the house wren consists of insects and spiders, I guess they have great experience in tracking down these sources of food. This is fortunate, because house wren nestlings have prodigious appetites. Although I saw my house wren nest in the oak woodlands of Sullivan Canyon, the house wren, as its name implies, often builds its nest in and around human habitations, choosing such items as tin cans; flowerpots; boxes and crates; pails; old boots, hats, coats, and shoes; and holes and crevices in walls in which to raise its young. Mathew Tekulsky writes a regular column about birding in his backyard and neighborhood in Bel Air, California. You can follow his encounters with the birds of the Santa Monica Mountains here on National Geographic News Bird Watcher every fortnight or so. Previous columns by the Birdman of Bel Air New Bird-Watching Column: "The Birdman of Bel Air" The California Towhee, Boldly Bland At Home With Hooded Orioles Scrub Jays Go Nuts for Peanuts Northern Mockingbird is a Wary Neighbor Christmas With the Pelicans California-Quail Close Encounter Yosemite Steller's Jay Encounter Banding Birds at Devils Postpile California Condor Close Encounter California Condor Rebound Going Nuts With Wilderness Ravens Hummingbird Chicks Fly the Nest Mexican Jays' Dogged Pack Mentality National Geographic BirdWatcher Regularly updated news stories, features, and columns about birds and birding Recent News Stories About Birds Migrating Birds Reset "Compasses" at Sunset, Study Says Bowerbirds Dance, Decorate to Suit Females' Changing Tastes Emperor Penguins: Uniquely Armed for Antarctica African Birds Understand Monkey Communication, Study Says After 400 Years, Cranes Return to U.K.Site Is Kept Secret |
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