Limburg serves up yet another jocular etymology, this time delving into the names of birds which are often, and not surprisingly, onomatopoetic. But how many know the difference between a buzzard and a vulture, or why English bishops were called magpies, or how close we came to celebrating Christopher Pigeon day? And of course there's the evolving slang meaning of cuckoo, the symbolism of the loon (crazy to us but a messenger of the gods in many cultures), and the black swan which signified a logical impossibility until he was discovered alive and well in Australia. A grab bag of curiosities. . . duck soup.