NESTS are made from things birds find in the environment. For those that live far from human dwellings, twigs and leaves predominate. For those that live in cities, the list of materials is more eclectic. Often it includes plastic bags, paper, aluminium foil, electrical cables and even cigarette butts. Most of these have been assumed to be the result of birds simply making do with what the urban world provides them, but a study just published in Avian Biology by Monserrat Suárez-Rodríguez and Constantino Macías Garcia of the National Autonomous University of Mexico has demonstrated that the cigarette butts are being woven into nests not by accident but by design.
Click on the link to read the rest of the article: Some birds use discarded cigarettes to fumigate their nests