Hate finding bugs in your home? Then you have something in common with Mexican house sparrows.  Plagued by mites and other parasites, birds sometimes incorporate insect-repelling plant matter into their nests.

However, Mexican researcher Monserrat Suárez-Rodríguez noticed that birds in Mexico City were making use of something unusual -- cellulose fibers from the filters of smoked cigarette butts.  These adaptable animals have aquired a new behavior that makes use of a ubiquitous man-made material with bug-repelling qualities.  Tests indeed show that birds preferred nests that contained the nicotine-saturated fibers, and such nests had fewer insect pests.

How exactly did the birds figure out how to adopt this new meme?  Did a few smart sparrows notice the advantage when accidentally incorporating the material into nests?  Birds are excellent observers, and experience with the Blue Tit's ability to open milk bottles shows a newly learned behavior can propagate quickly in bird populations. Alternately, perhaps the sparrows simply are adept at recognizing insect-repelling materials.  Either way, the birds appear to prefer the smell of tobacco butts to the presence of bugs.

Unless the birds have simply picked up the bad habits of their urban human neighbors!