TIL: In Mexico City, some bird species, like house sparrows and finches, use discarded cigarette butts to line their nests. Researchers believe the nicotine in the filters acts as a natural insect repellent, helping the birds fend off parasites such as mites and lice.

https://theworld.org/stories/2016/07/31/birds-use-cigarettes-snuff-out-parasites
#til #todayilearned
https://www.reddit.com/r/todayilearned/comments/1g7j1pu/til_in_mexico_city_some_bird_species_like_house/