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By Science News
When birds collide
In “Collision course” (SN: 9/21/13, p. 20), Susan Milius told the stories of two ornithologists working to develop windows that birds won’t fly into.
With few exceptions, readers were sympathetic to the plight of birds that either don’t see windows or incorrectly interpret reflections. William Thompson e-mailed about his Colorado home: “At the height of bird activity, we see about five such collisions per month with a 20 percent mortality rate. These collisions usually occur when there are a large number of birds flying, and the level of aggression/agitation is heightened. We suspect a significant number of these collisions result from the bird essentially attacking [its own reflection].” His response to the problem was to consider the underlying cause: “We readily admit that as the owners of an overly large house we are complicit in the more fundamental problem, faced by all species other than humans, which is loss of habitat. How about fewer people and fewer buildings?” Patricia Williams e-mailed that she was surprised when she moved from country to city to find that mourning doves would swoop onto her window ledge to eat birdseed without ever hitting the windows. “Maybe evolution will let the smart ones survive to reproduce, so none will require special windows anymore,” she suggested. But evolving window smarts sounds like a monster of a challenge, Milius says: “Glad to hear your doves coped, since mourning doves are among the species that surveys report finding dead at windows. Perhaps your window isn’t prone to tricky reflections, or the birds are aiming for the seeds on the ledge.”