Science: Flying Zoos

Britain has bird watchers for every hedgerow, but most of them do not scratch the surface of the bird world. The closest bird watchers in Britain are the learned Misses Miriam Rothschild and Teresa Clay, who comb the feathers of birds, probe their body openings, search through their nests with microscopes. They are looking for the lice, fleas, ticks, mites, flies, worms and other parasites which swarm over all birds. After many years of study, the Misses Rothschild and Clay have published a lively book, Fleas, Flukes and Cuckoos (Collins, London; 21 s.), packed with detailed information about the fascinating parasites that plague birds.

Fleas, say Authors Rothschild and Clay, are comparative novices in the bird-pestering business. They hop on & off as if they had a life of their own. But lice have been bird parasites as long as birds have been birds. They probably sucked the blood of reptiles from which birds developed. When reptiles' scales turned into birds' feathers, the lice learned to graze and flourish on the new crop.

The world now has about 8,500 species of birds and 25,500 species of feather-eating lice. Nearly every bird has a few lice, and some have thousands. Benjamin Franklin, the Misses Rothschild and Clay report, regretted the choice of the bald eagle as the emblem of America "as he is generally poor and often very lousy." As soon as infant birds climb out of their eggs, the waiting lice set upon them, chewing their feathers and nibbling their skins. They crawl into the throat pouches of pelicans and cormorants. One species feeds exclusively on the tears of swifts.

Along with lice and fleas, many other kinds of parasites swarm through the bird world. Ticks suck the blood of their hosts; mites live inside their feathers or even inside the bodies of their fleas.

Tapeworms bask in their intestines; protozoans, flukes and nematodes float around in their fluids. To Rothschild and Clay, a skylark is more than a blithe spirit: it is a flying zoo.

No mere cataloguers, the Misses Rothschild and Clay get a certain mischievous enjoyment out of their work with parasites. "The thought of a tapeworm as long as a cricket pitch [22 yards] living secretly in the stomach of a film star," they say, "arouses in us a feeling of macabre amusement . . ."