Earth Almanac: January/February 2007

Night Glider

Screech owls breed earlier than most birds so that when their owlets are being fed there will be an abundance of hatchlings, large insects, and rodents. Now, in open woodlands, orchards, and even city parks throughout most of the contiguous states, courtship is in full swing. But so nocturnal is this little raptor that you are more likely to hear it than witness it. If you’re east of the Rockies, listen for a mournful, descending whinny or a mellow, muted trill. On the Pacific side, the western screech owl utters a series of soft notes in increasing tempo or a short, slow trill. (Screech owls screech only when severely agitated.) The male approaches the female, calling from different branches. He bobs, bows, swivels his head, snaps his beak, offers food, even winks. If she accepts him, the two touch bills, preen each other, and usually bond for life. Screech owls cache food. And in warm weather they sometimes release blind snakes in their nest cavities. The snakes live in the debris, eating insect larvae and apparently reducing parasitism of nestlings. Owlets from nests with snakes have been seen to grow faster and survive better.

Beetle Art

Start researching bark beetles and you will find reams of literature on how to control them. But while a few species damage commercial timber stands—particularly monocultures—most attack only dead or moribund trees. And all native bark beetles play a vital role in forest ecology, providing food for insectivorous wildlife such as woodpeckers, encouraging shade-intolerant understory vegetation, and returning nutrients to the earth. It’s virtually impossible to find a woodlot in North America that lacks at least one of the roughly 600 species. Now is the time to look for the engravings, especially if you have companions who suffer under the delusion that nature shuts down in winter. Peel away dead bark, and you’ll find the tiny pupae and/or grublike larvae. But far more interesting and beautiful is the artwork—an egg tunnel excavated by the adult female with side galleries cut by the larvae and, depending on species, radiating from it in all manner of intricate and complex patterns. Bring charcoal and paper and make rubbings.