IN THIS LONG, LIKEABLE book Mary Durant and Michael Harwood illumine the many facets of John James Audubon. As an artist, he is shown to be a pioneer in both subject and technique. Many North American birds had yet to be identified, much less accurately depicted, when Audubon began to paint them in 1808. His technical innovation was to affix dead birds -- he shot many of them himself -- to wire armatures so that he could study their anatomies from any vantage point and portray them in action. (He made a point of painting birds as soon as possible after their deaths; to wait was to risk the fading of plumage.)

As a man, Audubon gives the lie to the stereotype of the birder as a fussy, verveless soul preoccupied with life-list-keeping. With his aquiline nose and the flowing locks that he liked to "undulate" for the ladies, he looked like Franz Liszt. But he was more flirt than philanderer, and his long-suffering wife's only complaint was that he spent too much time with the birds. He was a driven, rugged man whose day might start with a pre-dawn stalk and end with a post-midnight sketch. He worked so hard on his superb golden eagle painting that he collapsed and lay exhausted for days.

Audubon the writer was a phenomenon. English was not his native language. (Born in Haiti and raised in France, he didn't arrive in America until he was 18.) Nor was writing his natural medium. But he worked at it until he developed the colorful and exact prose style evinced in this account of daredevilry in Labrador.

"'It was a frightful thing to see my good Captain, Henry Emery, swinging on a long rope upon the face of a rocky and crumbling eminence, at a height of several hundred feet from the water, in search of the eggs of the Black Guillemot, with four or five sailors holding the rope above . . . When the friction of the rope by which he was suspended loosened a block, which with awful crash came tumbling down from above him, he, with a promptness and dexterity that appeared to me quite marvelous, would, by a sudden jerk, throw himself aside to the right or left, and escape the danger. Now he would run his arm into a fissure . . . . Whenever he chanced to touch a bird, it would come out whirring like a shot in the face . . . . After much toil and trouble he procured only a few eggs, it not being then the height of the breeding season. You may imagine, good reader, how relieved I felt when I saw Mr. Emery drawn up, and once more standing on the bold eminence waving his hat as a signal of success.'"

Audubon was also the honorary founder of the American conservation movement. Though he waged no formal campaigns -- he was busy enough trekking, painting and shepherding his magnificent folios into print, not to mention trying to collect from deadbeat subscribers like King George IV -- he warned his contemporaries that their slaughterous ways would likely exterminate the buffalo and other species.

Durant and Harwood's method was to dog Audubon's shade across North America, and part of their purpose was to see what has happened to his haunts. One expects the authors to sound the environmentl tocsin at the verge of countless dammed rivers and paved-over rookeries, and there is of this. But overall their findings are surprisingly upbeat: many of the wild places Audubon visited are intact. His fame is the apparent explanation for this staying power. Durant writes: "It begins to seem as if every other place where Audubon set foot in the nineteenth century was guaranteed to become a state park, a national forest, or an historic shrine in the twentieth century."

But the underlying motive for Durant and Harwood's 35,000 miles of driving and 600 pages of bookmaking was to vent a shared obsession with Audubon. "(At the end of the book Durant claims she knows Audubon better than she does Harwood, her husband.) Since they never say precisely why they find Audubon so mesmerizing, a fellow devotee might well offer his own explanation.

Audubon's fascination lies primarily in his ability to make birds live on canvas and paper. Trained in France by David, who was court painter to both Louis XVI and Napoleon, Audubon was so meticulous a draftsman that he took as much care with natural settings as with the birds themselves. (Once or twice he forgot himself and obscured his birds behind expansive foliage, like nudists in a PG movie.) He combined this exactitude with an unparalleled mastery of ornithology and a flair for capturing avian drama. The paintings in The Birds of america bring us so close to birds in their habitats that we feel aerodynamic ourselves. For all of his precision and science, Audubon was a supreme illusionist.