Tuesday, September 22, 2009

it's sparrow time!

It’s September, and the days are getting shorter at great speed. Today is the first day of fall, notwithstanding that the temperatures will be in the 80s in the Puget Sound area. Bird migration has been in full swing for almost three months, and most of the insect-eating birds have moved on southward. But the sparrows are still passing through at this time, some heading as far south as Mexico, others intending to hang around our area.

Why are there so many sparrows? Simple answer is that they eat the small seeds of small plants, and there are an awful lot of small plants out there. The seeds of many herbaceous plants are formed during the summer or fall, then hang around at or near ground level before sprouting into young plants the following spring. Before that happens, however, there is a whole winter of predation ahead of them and a whole array of predators lurking to pounce on an unsuspecting seed.

Insects eat the seeds, chipmunks and mice eat the seeds, and birds eat the seeds. Predominant among the birds are our native sparrows. Song Sparrows are probably the most common, but there are lots of wintering White-crowned, Golden-crowned, and Fox Sparrows as well, with smaller numbers of American Tree, Savannah, and Lincoln’s Sparrows.

Although not sharing the name, Dark-eyed Juncos and Spotted Towhees are common wintering birds also closely related to the native sparrows. In fact, all of them are closely related to the Old World buntings, and we should have called them buntings when common names were coined for them several hundred years ago. But we didn’t. Instead, we co-opted the name of an unrelated European seed-eating bird, the House Sparrow.

As all of these small birds eat small seeds, how do they avoid intense competition with one another? Turns out that each sparrow species has its own habitat preference, which means they’re not all feeding in the same place. Savannah Sparrows like open country and live and feed happily among grasses. American Tree, Golden-crowned, and White-crowned Sparrows like to feed in the open but need dense shrubbery to retreat into when threatened or spending the night. Song, Fox, and Lincoln’s Sparrows prefer dense shrubbery all the time, although they will often come out to the edge where they can be seen by birdwatchers.

Many of us—in fact, hundreds or thousands of us—feed these birds, putting out millet and mixed bird seed on the ground or in feeders, and they respond readily. If you’re lucky, you might have most or all of these species at your feeder if you live in the suburbs with good plant cover around your house. Watch them with binoculars to see how quickly and efficiently they crack and eat those seeds.

Dennis Paulson

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