Birds nest in tobacco stumps on purpose

In a recent Polish study, blue tit women’s tobacco use was monitored. Sinitiainen flew in Pirkanmaa in the spring of 2025. Picture: Jukka Ritola / Aamulehti

Monet Bird species all over the world deliberately collect cigarette butts in their nests. Some of the city’s songbirds even nest in ashtrays.

Fresh research again reinforcing the notion that they do so to ward off parasites. The research was also reported The New York Times (NOW).

Researchers from the University of Lódź in Poland followed blue tit, which are burrow nesters. A wooden hole is just as good for them as a man-made pit. Carrion flies and various blood tasters, such as ticks and fleas, also thrive in the blue tit’s nest.

They disturb adult birds and especially helpless chicks.

The researchers observed 99 blue tit in an urban environment and in a forest near the university. The researchers gave the birds three different types of boxes for nesting: conventional ones that the birds decorated themselves, sterilized ones with artificial moss and cotton, and boxes in which they placed two cigarette butts.

The researchers found that chicks in sterile nests and cigarette butt nests were healthier than those living in conventional nests based on blood tests.

The most parasites were in the usual nests. There were slightly fewer parasites in cigarette butt nests than in conventional nests. The least number of parasites were in sterile nests.

Cigarette butts especially used by house sparrows in Mexico, where the phenomenon has been studied for decades.

In addition to nicotine, cigarette butts contain thousands of harmful chemical compounds and heavy metals, which are obviously not good for parasitic insects.

One Mexican study found that the use of tumps also possibly improved the immune response of chicks. On the other hand, signs of genetic damage were observed in their blood cells.

The long-term effects of cigarette butts on birds are not yet known.

Having studied birds and tobacco for a decade in Mexico Constantino Macías García commented on the Polish study to the NYT and said it was significant.

However, he pointed out that in Mexico, house sparrows cut up tree stumps and spread them around the chicks’ nest. According to him, there might have been even fewer parasites in the cigarette packs of the Polish study if more caps had been placed.

Head of Polish studies Michal Gladalski told the NYT that the most difficult part of the research was getting the tummies. He doesn’t smoke himself, so the cigarettes had to be burned mechanically with logs.