Speaker 1: Welcome to brain stuff from how stuff works, Hey, brain stuff,
Speaker 1: Lauren Bogelbaum. Here, the house sparrows and finches of Mexico
Speaker 1: City may be proud to be called bird brains, and
Speaker 1: why not. They figured out how to use one of
Speaker 1: the grossest things on Earth, cigarette butts, to repel two
Speaker 1: of the other grossest things on Earth, ticks and mites.
Speaker 1: MoMA birds find their nests under constant and pervasive threat
Speaker 1: from these blood sucking, feather feasting ectoparasites. Country birds have
Speaker 1: easy access to nature's bountiful nest making materials, including certain
Speaker 1: insect repelling herbs and plants. City dwelling birds, on the
Speaker 1: other hand, face a concrete and steel urban landscape and
Speaker 1: must curate their nests from a more anthropogenic or man
Speaker 1: made palette enter cigarette butts. A study published in twelve
Speaker 1: in the journal Biology Letters details the ongoing investigation of
Speaker 1: an urban population of breeding house finches and house sparrows
Speaker 1: at the National University of Mexico in Mexico City. The
Speaker 1: author's found that both species interweaved anywhere from a few
Speaker 1: to a few dozen smoked cigarette butts into their twiggy
Speaker 1: eclectic domiciles. In fact, the study concluded, the more butts,
Speaker 1: the healthier the nest. Nicotine is an insecticide generated by
Speaker 1: the tobacco plant to ward off invasive leaf eating arthropods
Speaker 1: like beetles. Some residual nicotine remains in the fibers of
Speaker 1: cigarette butts that motherbirds used to line and insulate their nests.
Speaker 1: It turns out that this nicotine tinged filter fluff has
Speaker 1: medicinal and pesticidal properties that repel tis, in particular, protecting
Speaker 1: MoMA's chicks from a potentially lethal fate. Overall, the study
Speaker 1: concludes that the more cigarette filter fiber there is in
Speaker 1: the nest, the fewer ticks and mites, revealing persuasive evidence
Speaker 1: that parasites don't like cigarette butts and that nests built
Speaker 1: with these butts attract fewer parasites. But there's no Avian
Speaker 1: surgeon general, so who decides whether this seemingly beneficial cigarette
Speaker 1: habit harms the birds or is a savvy and resourceful
Speaker 1: example of urban wildlife adaptation. Researchers confirmed that there is
Speaker 1: some genetic damage linked to the activity, but they believe
Speaker 1: that the positive life saving anti parasitic effects far outwaigh
Speaker 1: any long term negative consequences. So you've come a long
Speaker 1: way Bertie's, and you're helping clean up our cities while
Speaker 1: you're at it. Interestingly, there's another way that birds may
Speaker 1: help combat cigarette but litter. A Dutch startup Crowded Cities
Speaker 1: is developing the Crowbar and Autonomous training device to teach crows,
Speaker 1: some of the most competent scavengers in the world, to
Speaker 1: deliver found cigarette butts to a trash receptacle in exchange
Speaker 1: for food reward. Today's episode was written by Carrie Tato
Speaker 1: and produced by Tyler Clang, with kind engineering assistance by
Speaker 1: Ramsey yungt. For more on this and lots of other
Speaker 1: bird brained topics, by which we obviously mean clever and helpful,
Speaker 1: visit our home planet, how stuff Works dot com.