UNIVERSITY PARK -- Lawrence Zeleny has already made his first visit of the spring to his bluebird nesting boxes.
Clearing out last year's straw and twigs, repairing the weathered wood boxes with his big, steady hands -- it's a labor of love he began nearly 25 years ago to provide nesting havens for the threatened songbird he has treasured since childhood.
"I feel if they're not being helped, they could be well on their way to extinction," said Dr. Zeleny, a former biochemist at the Beltsville Agricultural Research Center. "When I retired in 1966, I decided to devote the rest of my life to bluebirds."
At 86, he finds the ritual a bit more tiring than it once was. Failing eyesight has curtailed his driving and halted completely the identification banding he always enjoyed as part of his research.
But every spring, the bluebird man heeds the primal call and returns to the trail of 60 nesting boxes he set out on the spacious grounds at Beltsville as part of his retirement vow.
And early every Sunday during the nesting season, from late March until September, he'll spend four hours driving from box to box, lifting up the hinged lid of a wooden box to peer inside and check on the progress of another year's crop of baby bluebirds.
"They're very friendly and gentle, extremely beautiful, with their bright blue backs and rusty breasts," Dr. Zeleny said. "They have lovely, cheerful songs. Their whole manner is just so beautiful somehow."
In his 1976 book, "The Bluebird: How You Can Help Its Fight for Survival," he rhapsodized that the bluebird symbolizes "love, hope and happiness" and "seems capable of expressing almost every conceivable human mood and emotion."
But the eastern bluebird, Sialia sialis -- the dominant North American bluebird species, which breeds as far west as the Rockies and from southern Canada to Mexico -- has declined by as much as 90 percent in the past 50 years, he said.
At the small brick home south of College Park that he built in 1939, bluebirds haven't visited for at least 15 years. Development claimed open fields and eliminated natural nesting cavities the birds require in old trees or wooden fence posts.
The bluebird has suffered from the increasing use of insecticides, harsh winters and competition for vanishing nesting sites from two aggressive European imports, the starling and the house sparrow.
Millions of the birds died in rural areas of the South when they became trapped in stove flues protruding from tobacco-curing barns. "They're very curious and tend to look into any kind of opening at almost any time of year, not just nesting season," Dr. Zeleny said.
He can trace his interest in birds to his Minneapolis childhood. He recalls recuperating from a severe intestinal infection and watching, fascinated, as robins and sparrows cavorted in a nearby birdbath.
The bluebird first attracted his attention as a teen-ager. He began building and distributing the nesting boxes that are now the major thrust of the conservation effort, substituting manufactured cavities for natural ones.
However, it wasn't until he ended his 30-year research career that Dr. Zeleny launched the bluebird crusade. In 1977, he and a circle of enthusiasts founded the North American Bluebird Society, a Washington-based group with 5,500 members in the United States and Canada.
Through educational efforts by that organization, the Audubon Naturalist Society and regional bird clubs like the Maryland Ornithological Society, bluebird trails -- strings of nesting boxes that can be readily monitored during the season -- have proliferated.
"There's evidence in the last five or six years that the downtrend has leveled off," he said. "Some ornithologists dispute that we've had any overall impact. But we know this: In any area where there's a trail of good size, the local population goes way up."
Mary Janetatos, executive director of the North American Bluebird Society, credits Dr. Zeleny with inspiring legions of bluebird friends over the 20 years of their acquaintance. "It's his ability to rally others to the cause that really got it going," she said.
He remembers well-meaning Scout troops that spent entire winters building nesting boxes to exact specifications -- including perfectly sized holes big enough for bluebirds but too small for starlings -- and then placed them in inappropriate locations. "The most important thing is where they're put," Dr. Zeleny said, pointing out that the boxes should be no more than 5 feet off the ground, in open areas of quiet rural land or outlying suburbs where nearby shrubs and small trees provide perches for the fledglings.
Although bluebirds sometimes raise three broods a season, or as many as 15 to 18 babies, two broods are more common. The season in Maryland is already under way, and the birds are looking for nests. The first batch of eggs will hatch around May 6, the second around June 24.
In the late summer of 1971, Dr. Zeleny and his late wife, Olive, became foster parents to three orphaned baby bluebirds, a chaotic, emotional experience that became the subject of an article he wrote for the June 1977 National Geographic.
A year later, two of those orphans -- Little Brother and Little Sister -- mated and had babies of their own. Among his tender memories is watching their children from the first brood help Little Brother raise a late-season brood after Little Sister suddenly died.
From the book: "We are warned against ascribing human attributes to 'lower' animals. . . . Yet, when we study intimately the lives of individual wild creatures, we are often filled with wonder and may ask ourselves if we are really as superior to all the rest of God's creatures as our conceit has led us to believe."
Where to write
For more information about bluebird conservation, write the North American Bluebird Society, P.O. Box 6295, Silver Spring 20906-0295.