Do pigeons eat cigarette butts

Yes, I've seen it with my own eyes. Someone was feeding bread crumbs to a pigeon and the pigeon thought that an old cigarette butt was one of the crumbs. I wonder about the physical/medical consequences for the pigeon? I wonder if this happens a lot?

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Likely to be fatal. There is a very high amount of nicotine in the filter of a smoked cigarette.