Wednesday, March 1, 2006

House Sparrows Declining

Wednesday, March 1, 2006
The beloved (in England) and mostly despised (in North America) house sparrow (Passer domesticus) has declined in population by more than 50% since 1977, according to a recent study of the species reported on by the BBC.

It is hypothesized that the decline is linked to the availability and abundance of insect prey during the sparrows' spring and summer breeding season. Although house sparrows can survive just fine on a diet of seeds and other plant matter during the fall and winter, the protein-rich insect diet during spring and summer is crucial to the survival of offspring. Further studies are needed to determine if spiders, moths, and insect populations in general are declining, or if there is some other factor contributing to the noticeably lower reproductive success in second (later) versus first broods by house sparrows.

Here in North America, where the house sparrow is a non-native species, its populations are declining, too. But that is thought to be a good thing since house sparrows are fierce competitors for nesting cavities, often outcompeting native species such as bluebirds, swallows, martins, chickadees, titmice, certain flycatchers, and the smaller woodpeckers. Many nest box landlords "control" house sparrows by trapping and euthanizing them.

What a pity that we cannot create a new Marshall Plan for the house sparrow, where thousands of our non-native birds could be captured and transported back to their ancestral homeland.

Special thanks to KLo for sending along this newsy bird item to BOTB.