Yesterday was a day of triumph for Tom Lehrer. "It just takes a smidgen’ to poison a pigeon," the Harvard-educated comedian gleefully sang in 1959. "When they see us coming, the pigeons all try an’ hide, but they still go for peanuts when coated with cyanide." In his strained rhyme, Lehrer satirically worried about the response of the Audubon Society, but, as it turns out, his methods have finally earned the approval of animal-rights activists.