Poison

Anybody got any advice on how to poison birds? Went to check on the boat, which was in pristine condition when I left it after cleaning out all that water. Only to see that the friggin birds had gotten in again and shat all over the place. Can I be arrested for poisoning pigeons? Would it be worse to have dead birds but no shit in the boat? Can I hire somebody to sit in the boat in wintertime scaring off the birds? Perhaps a homeless? I'm getting desperate!