Tuesday, June 3, 2008

Bully Birds

It was a calm, warm evening when I went out back to resume my novel. A Carolina wren sang from the far corner of the yard, a pair of chickadees moved through the redbud tree and a family of mourning doves huddled on a maple limb. Then, by page two, the starlings arrived!

Several pair of these despised immigrants flew into the yard, followed by their noisy, demanding youngsters. As the frenzied parents searched the shrubs and lawn for insects, their ravenous offspring watched from nearby trees, squawking incessantly. Though obnoxious by our standards, this aggressive behavior is inherent in their species and explains why starlings, introduced to North America in 1890, have now colonized most of the Continent.

Favoring cities, towns and farms, starlings nest in cavities, either in trees or in the sides of buildings. Often raising three broods in the course of a summer, they begin nesting earlier than many birds, occupying cavities that might otherwise be used by native species (such as bluebirds, great crested flycatchers, wrens and prothonotary warblers). Worse yet, they also evict competitors from these nesting sites, consuming their eggs in the process. Producing four to six offspring with each brood, it is no wonder that these aggressive and prolific birds have been able to spread so quickly.

During the cooler months, starlings gather in huge flocks. While their aerial ballets can be spectacular in open country, their urban congregations produce sanitation nightmares. On the positive side, these "ugly, obnoxious aliens" consume a prodigious number of harmful insects and, we must admit, they are one of nature's success stories.