The study, headed by ecologist Monserrat Suarez-Rodriguez, provides "the first evidence that smoked cigarette butts may function as a parasite repellent in urban bird nests," the abstract states. The report was published online Dec. 5 in the Royal Society publication Biology Letters.
House sparrows and house finches, the two birds studied in the report, are sometimes blighted by parasitic mites.
"The amount of cellulose acetate from butts in nests of two widely distributed urban birds was negatively associated with the number of nest-dwelling parasites," the study concludes. It goes on to suggest that nicotine is what drove the parasitic mites away.
Cellulose acetate is a major component of cigarette filters.
While Nature notes that birds have been known to incorporate plants that ward off parasites into their nests, the study holds that its observations are "consistent with the view that urbanization imposes new challenges on birds that are dealt with using adaptations evolved elsewhere."
The AFP reports that nicotine, a highly toxic byproduct of the tobacco plant, has also been used in some pest repellents for crops and in controlling poultry parasites.
Nicotine was used as a treatment for intestinal parasites the 19th century. The 2008 edition of the U.S. Air Force Survival Handbook notes that in extreme cases, eating a single cigarette can be used as a field remedy for intestinal parasites.