Sparrows are incredibly adaptable and can be found in the most unexpected places. They have been known to sleep in birdhouses, tuck themselves into the crevices of old fences and even huddle together for warmth on cold nights.
Sparrows spend their days hunting for food – everything from insects to weed seeds and restaurant leftovers if they can get them. By the time sunset comes around they’re pretty tired from all that activity, but sleeping is usually the last thing on their minds. Then they move to a “pre-roosting site,” hopping and flapping their wings frantically as they go. All that commotion is supposed to alert other sparrows it’s time to head off to their communal roost.
During the spring and fall migrations, white-crowned sparrows are sleep-deprived, getting about a third of the amount of rest they normally get. Niels Rattenborg, a researcher from the University of Wisconsin-Madison, caught 30 sparrows in Fairbanks this summer with a mist net and brought them back to his lab in Madison. Rattenborg wanted to know if the birds would still be able to navigate, avoid predators and find food while sleep-deprived.
Rattenborg discovered that his caged sparrows performed much better on a memory test while they were sleep-deprived than they did while getting plenty of rest. He also learned that the birds huddled together when the weather turned cold, probably to stay warm and protect themselves from predators and harsh elements. Unfortunately, the same habits that help the sparrows survive in their natural habitat can cause trouble for homeowners. They often stuff their nesting materials into dryer, stove and fan vents, which can damage them and block proper airflow. They’ve also been known to roost inside sheds and garages, where they can attract rodents and other unwanted guests.