Spring moves up the United States at the average rate of about15 miles a day, according to naturalist Edwin Way Teale. It spreads forward, climbing mountains at the rate of 100 feet a day. ''It sweeps ahead like a flood of water, racing down the long valleys, creeping up hillsides in a rising tide,'' he wrote.
Edwin Way Teale wrote for a wide audience that included both the scholar and the popular reader. He edited Thoreau's ''Walden'' and even revised the insect-study program for the Boy Scouts of America. When he died in 1980, at the age of 81, he was one of America's best loved naturalists.
He had received some of the highest honors, among them the 1966 Pulitzer Prize for general nonfiction for this book, ''Wandering Through Winter.'' This was the final volume in a series of four books, each focusing on one of the seasons. He had spent 15 years writing and researching them, traveling some 75,000 miles.
For the first book in the series, ''North With the Spring'' (Dodd, Mead & Company), Mr. Teale made a 17,000-mile journey, beginning in the lower part of Florida, in January. From there, he followed the spring as it moved up the United States. He ended his trip June 21 at the Canadian border.
First published more than 40 years ago, this book looks at spring not as a change that occurs around us but as an ascension, a movement north, a movement visible only in its effects. Mr. Teale believed that the out-of-doors ''contained something more, something magical, something that fills a deep need in the human heart.'' And his book suggests that same spirit. The book would be a pleasure to read in any season. But spring seems perfect. Like spring, it brings together science, poetry, wonder and love.
His trip started somewhere south of Lake Okeechobee, where spring begins in the North American continent. There in lower Florida, thousands of tree swallows swirled like a great wheel in the sky as they moved north. These clouds of white-breasted birds, according to Mr. Teale, are one of the first signs of spring. The season has no definite starting point, but here, in the Everglades, he wrote, ''it comes into being, swells, gains momentum.''
The angle of the sun's rays becomes less oblique. Twilight lengthens. Orion rises earlier. A green haze creeps over the cypress trees. Pillars of smoke from wildfires shift around the horizon. The sun rides higher. Birds swarm above the sawgrass.
From the Everglades, Mr. Teale went north, zigzagging by car behind the advancing spring's front. He trailed the season through 23 different states, over the Great Smokies, across the Piedmont Plateau, among the Jersey pine barrens, out to the tip of Cape Cod, through the mountains of New England and to the Canadian border.
As he drove, he anticipated the day (for 1992, it is March 20, at 3:48 a.m. EST) that marks the official starting of the season. One minute it would be winter. The next minute, the rays of the sun would fall vertically on the equator. And it would be spring. According to the astronomers, such a hairline exists, he wrote. ''But in nature, all is fluid and divisions are blurred.''
The first day of spring is not necessarily the first spring day. It can come earlier or later. Spring, Mr. Teale said, is the time when all things seem possible. ''It is a blank page,'' different for each of us.
For the robins, spring comes with the earthworms, when the frost is out of the ground. For the ruby-throated hummingbird, spring comes with the nectar-laden flowers. For the honeybees, spring comes with the pollen.
''These months with music in them form an event in every life . . . ,'' Mr. Teale explained. As he traveled, he saw those events. In the Louisiana lowlands, yellow flowers topped the mustard greens. In Georgia, goldfinches migrated, ''flashing gold and black between moss-hung boughs.'' Farther north, oaks became splotched with red, pink, brown, green and purple lichens. Farther yet, a mountain flower opened its white petals. At dusk, the whippoorwill repeated his call.
Spring ends so abruptly only on the calendar, Mr. Teale decided as he concluded his trip. In reality, spring doesn't end. It passes into the sky. It spreads until it is swallowed up in space, like a sound. Spring is like life, he added. ''You never grasp it in the entire; you touch it here and there. You know it only in parts and fragments.''
Diane Scharper teaches writing at Towson State University.