If you’ve seen house finches flying around with cigarette butts in their beaks, rest assured that these birds are not smoking. They are using the cigarette butts to line their nests.
At the end of June, the Journal of Avian Biology published a paper by Monserrat Suárez-Rodriguez and Constantino Macías Garcia, who presented the results of an experiment they designed to find out what was going on with the cigarette butts. Initial evidence suggested that nicotine and other chemicals in the butts might function as an insect repellent—after all, nicotine is used in some pesticides—but the evidence wasn’t conclusive.
