FEW ANIMALS ON EARTH can rival birds in their effortless mastery over air, water, and land. Perhaps this accounts for their special magic to humans, who have gained similar mastery only with ungainly, massive machinery. The adaptations birds have evolved in response to their varied environments are wonderful and strange, but few are stranger than the unlikely habit of tunneling underground. The subjects of both these lovely books are birds that nest in burrows.

Far from sight of land in the wilderness of waves, wind and sky, fishermen and sailors for centuries have been gladdened by the sight of darting flocks of small sea birds that skip from wave to wave on pattering feet.

Fishermen long ago named the little birds petrels in honor of St. Peter, the Biblical fisherman of Galilee who walked on water. Petrels do not actually "walk" on water, but skim the waves with wings outstretched to catch updrafts from the turbulent waves. Petrels are some of the earth's most extradionary wanderers. They are found on every sea. The open sea is their true home, for these little birds spend all of their lives on the ocean, coming ashore only to breed and raise their young in the burrows of their breeding grounds.

For half a million years, the Bermuda petrel has returned year after year to Bermuda and its outlying islands in the Atlantic Ocean, its only breeding grounds on earth. Once, multitudes of Bermuda petrels nested on the main island every year, undisturbed by man or any predators more threatening than gulls and other sea birds. With the settling of Bermuda by Europeans in the early 1500s came hogs and rats which decimated the petrels' defenseless nests. Settlers and sailors found the fearless, gentle, adult birds to be tasty, nourishing, and easy to catch. By 1620, there were no more petrels to be found. For 300 years not a single Bermuda petrel was seen, and the little bird was believed to be extinct.

Bermuda Petrel, the Bird That Would Not Die is the moving story of the discovery and rescue of a few living Bermuda petrels in the 20th century. Its heroes are a lighthouse keeper, an aquarium director, a compassionate U.S. Army officer, scientists from the American Museum of Natural History, and most of all, a young Bermuda boy with a passion for wild creatures.

In 1951, the last seven pairs of Bermuda petrels on earth were found nesting on an outlying island of Bermuda, threatened with certain extinction by predators and DDT contamination carried through the ocean food chain from distant continents. David Wingate, the Bermuda boy who loved animals, was invited on the expedition that discovered the birds. Years later, he returned to Bermuda from college and dedicated himself to studying and protecting them. Today, as Bermuda's chief conservation officer, he is proud guardian of 100 Bermuda petrels, including 30 nesting pairs.

Bermuda Petrel is a true tale of unusual respect and cooperation between scientists and a child who together managed to save a species from extinction. Ted Lewin's fine black and white illustrations are equal to the drama of the story.

The Bermuda petrel is so rare it has never been seen at sea, and you will not find it even in most bird books. Its cousins, small soot-brown birds affectionately known as Mother Carey's Chickens (storm petrels), are far more numerous and well-known world-wide. Once a year, they gather in Antarctica to nest in burrows lined with penguin feathers. Burrowing Birds tells the life history of these small world travelers and the unusual habits of other birds who nest underground.

Birds as different as petrels, swallows, burrowing owls, kiwi's and kookaburras make their nests in burrows. Kingfishers, cousins of the kookaburra, tunnel into the banks of streams and rivers. The nest of the mysterious African river martin was discovered only 60 years ago in river banks that were submerged for most of the year. The sociable sand martins (bank swallows) of England nest in communities of burrows which they help other dig. The fairy prion of New Zealand (another kind of petrel) shares its nest burrow with a three-eyed reptile, the tuatara.

Burrowing Birds is thoughtfully supplemented with a list of scientific names and an index. Joel Schick has provided handsome black and white portraits of the 18 species in the text.

These two lively, informative books are a compliment to the intelligence of the young reader, and a pleasure for inquisitive readers of any age who delight in the ways of wild things. They are a fine introduction to the wondrous diversity of life, its tenacity, and its awesome vulnerability to human interference.