This is an odd one, but it makes perfect sense. I hope the birds in question don't have much sense of smell, or don't mind the smell of ashtrays.
City birds use cigarette butts to smoke out parasitesLining nests with material from discarded cigarettes may help keep out parasitic mites.
Stuffing cigarette butts into the lining of nests may seem unwholesome. But a team of ecologists says that far from being unnatural, the use of smoked cigarettes by city birds may be an urban variation of an ancient adaptation.
Birds have long been known to line their nests with vegetation rich in compounds that drive away parasites. Chemicals in tobacco leaves are known to repel arthropods such as parasitic mites, so Monserrat Suárez-Rodríguez, an ecologist at the National Autonomous University of Mexico in Mexico City, and her colleagues wondered whether city birds were using cigarette butts in the same way.
In a study published today in Biology Letters1, the researchers examined the nests of two bird species common on the North American continent. They measured the amount of cellulose acetate (a component of cigarette butts) in the nests, and found that the more there was, the fewer parasitic mites the nest contained.
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As well as having anti-parasite effects, Suárez-Rodríguez cautions there may be as-yet unknown negative effects for the birds, because many compounds in cigarette butts are known carcinogens, and some are pesticides.
Interesting adaptive behaviour from our friends of the chirpy persuasion.
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Devious, treacherous, murderous, neanderthal, sub-human of the West.