THE LONG, crooked necks of cranes may not seem especially sexy to a human, but they are quite important to the mating success of these birds, an Ohio State University researcher has found. Cranes are known for loud, raucous calls, said zoologist Abbot S. Gaunt. ``We think they are built a lot like a violin with hollow bodies that act as a resonating chamber for the sound,``Gaunt said. ``Our research suggests the birds` long necks contribute more to the volume of the calls than to their pitch. `` Gaunt has found that when the cranes are surgically altered so they lose the vocal function of their necks, they also lose their sex appeal to other birds. ``One of the male birds restricted in this fashion produced a weak buzz instead of his customary blast. His nearby mate then ignored the muffled male,`` he said. Zoologists aren`t sure why cranes like their mates to be so loud. Gaunt speculates it may be ``the cocktail party phenomenon``--meaning that in an enormous flock, a bird has to be loud to be heard above the din of the others.