Blue Jays Eating House Paint
During the winter of 2000-2001, Deborah Jasak called to report Blue Jays chipping the paint off of her house in Hopkinton, New Hampshire (pictured left). We asked other participants if they had similar experiences and heard some interesting stories. The reports from that year, as well as some theories about the behavior, were gathered into a Summer 2001 Birdscope article.
An investigation into paint ingredients found that limestone, a source of calcium, is often a key ingredient in paint. Scientists theorize that Blue Jays are eating paint chips for the calcium. Deborah Jasak and others found that offering eggshells, another good source of calcium, stopped the paint-chipping behavior. If Blue Jays are chipping the paint on your house, consider offering them eggshells after sterilizing them by boiling or heating in a 250 oven for 20 minutes.
After the Birdscope article was published, more reports came in, and new information about the relationship between acidic soil and calcium availability in the northeast came to light. An updated article, published in the January/February 2003 issue of Bird Watcher’s Digest, incorporates the new information and points out that Lab scientists believe the Blue Jays are stashing away, or caching, calcium for spring. Scientists theorize that the Blue Jays, especially in the northeast, may cache calcium before the breeding season because naturally occurring calcium may be in short supply.
Learn more about the Lab’s research on acid rain and it’s effects on breeding birds.