You know which animal is always credited as being man’s best friend. But try on this flighty idea: Man’s best friend may well be the common pigeon.Pigeons don’t deserve their icky reputation, the National Audubon Society insists. They’re not dirtier than other animals and they don’t really spread disease. But they sure seem to upset some sense of natural order. Maybe that’s thanks to the unwanted gifts they drop from above. Or because they seem unperturbed by the supposed supremacy of people. Urban bottom-feeders like mice and raccoons usually retreat when we’re around, but “rats with wings” don’t care. They just go about their business.In fact, pigeons are intelligent, trainable, darned fast and amazingly storied. They’ve played fascinating roles in human history — starting in ancient Egypt, where messenger pigeons spread the word about Nile River flooding, and in ancient Greece and Rome, where they carried military messages, shipping news and even results of the earliest Olympic Games.Meanwhile, the ancient Greek poet Anacreon, a legendary drinker and partier, found another great use: trawling for girlfriends with verses distributed by bird:“Oh, beauteous little pigeon, Say wither art thou flying? …”“Anacreon has sent me … for one sweet little lyric …I carry singing letters to one maid and another …”This poetical pigeon goes on to swear that he’ll never quit Anacreon because “pecking his bread, and drinking out of his own sweet wine cup” is one plum gig.Other historical pigeons had it tougher. For one thing, they’re reportedly delicious. Even as they took off as trainable novelties and pretty pets in the 19th century, they also started invading rooftops and park benches, earning that backlash of fear and resentment. The North American passenger pigeon wound up hunted to extinction over a century ago.