Birds are his lifelong calling Tireless: His decades of devotion to winged creatures has won the ornithologist international acclaim.

On the Bay

June 28, 1996|By Tom Horton | Tom Horton,SUN STAFF

DAWN ILLUMINATES what increasingly passes as forest nowadays in suburban Maryland -- a small wood lot, bounded by Trade Zone Avenue and warehouses in a Prince George's County industrial park.

The traffic's whoosh from U.S. 301 is beginning to swell. At wood's center, Chandler Robbins, one of Maryland's and the world's great ornithologists, checks his watch: 5.30 a.m.; time to listen to the songs that will tell volumes about this humble spot.

Robbins, a man Roger Tory Peterson once said had "the best ears of any birder I have ever known," puts in his hearing aids and begins making notations on his clipboard almost nonstop:

One cardinal calling, and there a yellowthroat; crows, just flying over; two cardinals now, and two catbirds; outside the wood lot, an indigo bunting; within 50 meters, an Acadian flycatcher, surprising for so small a wood, and by his chirping, agitated.

All this and more -- cloud cover, wind, temperature, another flycatcher, towhees -- goes down on the charts, even, later on, such subtleties as "a blue jay imitating a red shoulder hawk."

The hearing aids (he needs them only for high frequencies, as in bird calls) seem Robbins' sole, minor concession to turning 78 next month. He is still on the job after 50 years as a federal biologist at the Patuxent Wildlife Research Center near Laurel.

He's as respected as a birder can be -- senior author of the classic "Birds of North America," developer of the Breeding Bird Survey that has become the premier method for understanding what is happening to bird populations throughout the world.

He has been honored from Guatemala, which named a research station after him, to Maryland, where College Park recently gave him an honorary doctorate.

The attention has come unsought to Robbins, who seems the very antithesis of trendiness and publicity-seeking. His hairstyle looks virtually unchanged in photographs covering five decades. Job, home, wife -- all have also remained the same in that time; even his Bushnell "Featherlight" binoculars, dented and worn shiny, are 35 years old.

A newly hired intern could not be more enthusiastic, or move at a faster pace, going about Robbins' routine among ordinary suburban wood lots on a recent morning.

It is part of an effort to help Prince George's County retain and enhance its forests by documenting how the size and shape of small, wooded tracts relate to the numbers and types of birds there.

It is his calling national and international attention to the so-called "fragmentation" of our forests that is one of Chan Robbins' finest legacies.

As well as anyone in America, he has championed a more refined conception of the qualities of forest that lie beyond mere overall acreage.

To grasp the concept of fragmentation, one can start where much of Robbins' favorite bird-watching still occurs, in his own 2.5-acre wooded yard. Nearly a dozen species that nested there half a century ago no longer do.

His woods look the same but sing a different, diminished song. "My yard hasn't changed but all around us has; same old story everywhere," he says.

A key to such bird declines, Robbins has shown, is the loss of unbroken blocks of forest. Whether fragmented by roads, fields or power lines, the effect is more forest edge, and less forest interior.

Many species thrive along forest edges. Because this includes huntable creatures like turkey, deer and quail, traditional wildlife managers have actually worked to create edge habitat.

But nowadays, too much of the forest in places like Maryland is virtually all edge. Many birds, unless they can nest at least 100 lTC meters deep in the forest, are susceptible to destruction by edge-loving species that prey on their young.

Some edge dwellers like the cowbird act as parasites, laying eggs in forest dwellers' nests, forcing them to raise young cowbirds instead of their own.

In a seminal 1989 paper, Robbins linked these problems with declines among Neotropical migrants -- species that migrate annually between here and the tropics. These include most of our familiar songbirds, more than half of all the birds nesting in North America.

To preserve the full natural variety of such nesting birds in an area, intact forests of at least 6,000 acres (about 10 square miles) are ideal.

Research at places like Patuxent has shown that where this is impossible, preserving parts of the forest like stream valleys and river bottom land can help compensate. Another strategy is to manage forest shape to maximize interior over edge (for example, circular or square, instead of rectangular or oval).

Robbins, who has documented many a problem with his beloved birds, has "no plans to stop working" and retains a fundamental optimism.

He has seen his priorities for emphasizing forest interior habitat incorporated in Maryland's Critical Area and tree preservation laws -- "well ahead of what most states are doing," he says.

And the day before our meeting had come the triumphant closing of a circle for Chan Robbins.

Almost 50 years ago this spring, as a young biologist, he discovered an extraordinary forest in Prince George's County, the Belt Woods. Among its centuries-old oaks, he documented one of the highest densities and varieties of breeding birds in North America.

With Robbins at his side, Gov. Parris N. Glendening stood by the now-famous woods and announced it was being purchased for $4.5 million to preserve it from development.

Pub Date: 6/28/96

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