Mexican House Finches Use Cigarette Butts as Nesting Material

[FamTimes reporter Park Joo-hye] Birds have been found to use seemingly useless cigarette butts as material for building their nests.

Researchers said Mexican house finches living in Mexico City build their nests with cigarette butts to drive out mites, despite the adverse effects that toxins in the butts can have on chicks.

To build on the findings of a study conducted in 2012, researchers at the National Autonomous University of Mexico recently investigated whether Mexican house finches use cellulose fibers from cigarette butts as insulation or for health-related reasons.

The researchers said, "One possible reason birds extract cellulose fibers from cigarette butts may be that the fibers resemble feathers."

To test their theory, the researchers introduced large numbers of live or dead mites into various nests. They also replaced the cigarette butts with felt in nests where chicks had hatched.

The researchers' observations showed that the birds were using discarded cigarette butts to eliminate mites and other parasites. Birds in nests where live mites had been introduced used 40% more cigarette butts.

It has not been established whether nicotine from cigarettes has the beneficial effect of keeping mites away. However, the nicotine can cause severe adverse effects in chicks. According to a 2014 study by the same research team, chicks living in nests containing more nicotine experienced more chromosomal abnormalities.

On the other hand, when nests contained fewer parasites, more chicks hatched safely and developed healthier immune systems. The birds therefore appear likely to continue using cigarette butts for their short-term benefits. This is because chromosomal abnormalities do not cause any problems until the chicks have matured, left the nest and begun reproducing.

The researchers argued that further research is needed to determine the long-term effects of cigarette butts on birds.

Reporter Park Joo-hye, fam1@pcss.co.kr