In one of those “I’m not sure what to think about this” stories, the Economist reports that birds use cigarette butts to fumigate their nests for parasites.

On the one hand: clever birds! On the other: hmmm, I can think of several potential toxic side effects for the birds.

Definitely a human-animal interaction, though, and probably a misunderstanding on both sides (at least until now), so I thought I’d mention it here.