THE AUDUBON SOCIETY BOOK OF WILD ANIMALS, by Les Line and Edward R. Ricciuti (Abrams, $37.50) is simply delicious. The work of two editors and 90-odd of the world's best nature photographers, this huge and handsome book is a companion to the equally delicious The Audubon Society Book of Wild Birds, published recently. Wild Animals is an eloquent photographic plea for better understanding of and protection for the world's mammals. The book is divided into animal groups. There are, for example, sections on "The Hunters: Dogs," and "The Hunters: Cats." And essay, sketching some interesting information about the animal group, precedes each photographic section. One of the most fascinating is "The Weasel Clan" or mustelid family, the one capable of spraying rank odor, of ferocious behavior and the most diverse group of meat-eaters.

MOMENTS OF DISCOVERY, by Eliot Porter and Michael Harwood (Dutton, $29.95) is the collaborative effort of editor-author Michael Harwood and bird photographic Eliot Porter (once a physician and teacher at Harvard Medical School). Harwood's essay takes one through the evolution of serious ornithological research in the United States from the first intrepid explorers to today's researchers; many of the great names will be familiar to birders. Then come Eliot Porter's incomparable photographs of birds - mostly nesting birds and their nestlings. The impression is that each photo is better than the one before it. The truth is they are all magnificent. So are the captions. Monents of Discovery is a grand book and has a grand title - most birders can remember everything about that moment of discovery years and years later.

THE NATIONAL PARKS, by Michael Frome (Rand McNally, $29.95) is a somewhat lesser effort. To be sure, the photographs of and in each of the nation's 37 national parks are first-rate. And photographer David Meunch has a good eye, a good sense, and an obvious love of his subject. One wishes there were more photographs, just as one whishes there were more national parks. Michael Frome is an Alexandria resident and author of the annual Rand McHally National Park Guide. His introductory essay is an intelligent and measured plea for conservation. The essays that accompany Meunch on each of the photographer's rounds are personal sketches of the parks, their origin and some of the more interesting people who are associated with them.