The ivory-billed woodpecker flourished in the swamp forests of the Southeast, inspiring such awe that people who saw one unfold its 3-foot-wide wings and swoop up to sink its razor-sharp claws into a cypress tree could only exclaim, “Lord God.”

The ivory-bill had dozens of nicknames, including white-back, pearly bill, poule de bois and King woodchuck. But Lord God bird was the name that seemed to tell it all.

The strikingly beautiful bird was more often heard than seen. Its call penetrated the forest, the two-note rap of its jackhammer-like bill helped pinpoint its location and a scraping sound could be heard as the hungry woodpecker peeled bark from dying trees to get to the fat beetle larvae, or grubs, that were its sole source of food.

Sadly, in recent years the ivory-bill has neither been seen nor heard. The last documented sighting in the United States was in 1944 in northern Louisiana’s Singer Tract, the vast forest where the bird made its last stand.

It was spotted more recently in the mountains of eastern Cuba, the last time for certain in 1987. Although occasional rumors of sightings persist, it appears that the bird has become extinct.

The saga of what was regarded as America’s rarest bird, the forces that led to its demise and the Herculean race against the clock to save it are detailed by Maine author Phillip Hoose in “The Race to Save the Lord God Bird,” (Farrar, Straus & Giroux, $20).

The bird, which thrived throughout much of the South, was prized by Indians, who believed that its white bill possessed magical powers. The ivory-bill was targeted by hunters in the 19th and 20th centuries. Like other species, it was sought by milliners for its fashionable plumage; as the bird’s numbers dwindled, specimens fetched ever higher prices from museums and individual collectors.

The biggest threat, however, was posed by the shrinking habitat and the ivory-bill’s inability to adapt by finding a food source that would substitute for grubs.

The last ivory-bill sighting came in the Singer Tract, named for the sewing machine manufacturer which relied on the stands of giant oak and sweet gum trees that became raw material for cabinets to house its machines. The bird’s fate was sealed when Singer sold cutting rights on 73,000 acres to the Chicago Mill and Lumber Co., which built railroad tracks into the forest to accommodate its relentless logging operations.

Even when it seemed during World War II that a lack of manpower might halt the cutting, fate conspired against the bird. German prisoners of war were put to work as loggers to keep production on track.

Hoose’s book is a fast-paced tale that parallels the emergence of America’s conservation movement and features heroic figures who comb snake-infested forests in search of the ivory-bill and then try to enlist political leaders and the public on its behalf.

“I wanted to write a book about extinction, and I wanted to show that extinction is tragic and preventable. And I think the best way to do this is to tell people a story,” said Hoose, a Portland-based author and conservationist who has worked for the past 25 years as a habitat expert with the Nature Conservancy.

A vague familiarity with the ivory-bill turned to fascination in the mid 1970s, after Hoose read a book by James Tanner, the ornithologist who championed the bird’s cause and linked its disappearance to its shrinking habitat. Hoose himself searched for the woodpecker in the steamy Big Thicket Swamp of Texas in 1980 and more than two decades later made three trips to Cuba to gather material for his book.

The closest he has come to seeing or hearing an ivory-bill was holding specimens, viewing pictures and drawings, and hearing tapes. Yet Hoose’s affection for the big “star-quality” wilderness bird comes through amid every twist and turn in his narrative.

“I wanted people to love the bird. I wanted people to root for it to survive. I wanted people to feel saddened as the numbers dwindled and the stage shrunk,” he said.

During his research, Hoose interviewed Tanner’s 87-year-old widow, Nancy, one of the last Americans alive today who has seen the ivory-bill. Tanner was with her husband in 1941 when they spotted two of the birds in the Singer Tract.

In the decades that followed, during vacations and canoe trips on Florida’s Suwanee River or South Carolina’s Santee, the couple kept up their search, but to no avail.

Tanner, of Knoxville, Tenn., is enthralled by Hoose’s book and hopes it finds a wide audience.

“He’s showing how sad the extinction of a species can be,” she said. “He used the ivory-bill and Jim as an example, but it’s more about conservation and preservation than just a story about the ivory-bill.”

It was Hoose’s idea to position the book for the children’s market, in the young adult category. His previous book, “We Were There, Too! Young People in U.S. History,” was a finalist for the National Book Award, and he is comfortable writing for that age group.

Although he hopes that “The Race to Save the Lord God Bird” will also attract adult readers, Hoose would like to see it used in schools as a teaching tool. To that purpose, the book is filled with sidebar materials on topics ranging from the extinction of the once-abundant passenger pigeon to the unique species of birds, butterflies and scorpions found in Cuba.

If the story of the ivory-bill is a parable or morality play for our times, Hoose said it’s one that offers hope.

“We have tools now to save birds and to save habitat that didn’t exist when this story was told,” he said, hailing the successes achieved by land trusts and the Endangered Species Act as well as the exponential growth in the popularity of bird-watching. “And we have, to some extent, an environmental ethic in this country, although we have to fight to preserve it,” he said.