Caution amid official rejoicing

ON THE BAY

Protection: By the middle of next year, the bald eagle will be heralded for its comeback from the endangered list, but questions linger about its future in the region.

October 01, 1999|By Tom Horton | Tom Horton,SUN STAFF

ON JULY 4 of next year, if all goes as federal wildlife officials plan, the bald eagle will be celebrated as officially "recovered," a triumph for the Endangered Species Act that protected it for 33 years.

So why won't Virginia ornithologist Mitchell A. Byrd, dean of the Chesapeake's eagle researchers, be cheering?

His reasons are caution about eagles, but also about assuming too readily what a sustainable balance between people and the rest of nature truly requires.

Byrd and his colleagues at the Center for Conservation Biology, at the College of William and Mary in Williamsburg, agree that the bald eagle has made an inspiring comeback.

Look at the numbers:

Breeding pairs of Haliaeetus leucocephalus (white-headed sea eagle) in the Chesapeake Bay region are around 600. That equals estimates of 60 years ago, before DDT and other pesticides reduced eagles here to their low of 80 pairs in 1978.

To put the comeback in perspective, the pristine bay of 500 years ago probably supported higher densities of bald eagles than any place but Alaska, maybe 3,000 breeding pairs.

Still, the current numbers, which Byrd says will probably rise, handsomely exceed the numbers required to "delist" the eagle and remove it from protection of the Endangered Species Act.

But the act, Byrd points out, is about more than numbers of a species. It is about habitat, the ecosystems that sustain it.

And here is what a white paper from the Center for Conservation Biology has to say about the larger context for eagles:

"Can we sustain a recovered population? Virtually every biologist that has worked closely with the population now feels that habitat loss rates will result in a population reversal in the foreseeable future."

Broadly, this concern stems from increasing human population in the bay watershed -- 16 million, headed in the next couple of decades toward 19 million.

That understates the potential for problems, according to the center's study.

Human population pressures are not spread equally among the 41 million acres of the watershed. Rather they are focused along waterfront, where we love to live and enjoy the recreation; where industry has access to shipping and cooling water; where sewage plants delight in the dilution.

For all these uses, the Chesapeake is well endowed, epitomized by a long, meandering tidal shoreline -- some 9,000 miles in an estuary 200 miles long.

And on this edge, the white paper shows, the bald eagle is quintessentially dependent. Of 367 historic nesting sites examined, 95 percent were less than two miles from open bay or the main stems of rivers; 60 percent were within a half-mile.

Eagles do almost all their feeding -- diving on fish -- within 100 yards of shorelines. They spend 90 percent of their time on perches, usually tall trees close to the water's edge (I canoe a creek in Talbot County where each summer you can see young eagles learning to fish, gliding from "perch trees" to the water).

Other studies confirm that eagles do not easily share the edge with human activities. Historic nesting sites that have remained undeveloped have been recolonized as the birds came back. Others, even with minimal development, or with human boating activity nearby, have not been recolonized.

Byrd says he and his colleagues have observed four cases this year of eagles nesting on duck blinds, channel markers and transmission towers.

In only one case was there successful reproduction, he says. Eagles also are nesting increasingly inland, in areas of the Piedmont where not as much habitat supports them.

"You could argue this is all evidence they are more adaptable than previously thought, but my guess is it is evidence of birds being pushed out by habitat limitations," he says.

While no one keeps statistics on the erosion of good eagle habitat, "I have been flying the bay for 23 years now [surveying nests]," Byrd says. "I get a very clear overview of what's going on along the waterfront, and it's not good."

How close are eagles to exceeding the bay's carrying capacity? One scenario in the white paper, based on development trends, shows an increase continuing a few more years to a decade, then a reversal.

Eagles, and their nesting, will remain protected under other federal laws. But the delisting, taking away the Endangered Species Act's broader focus on habitat and on closely monitoring eagles' status, raises "grave concerns" for the long term, the white paper says.

Byrd feels the rush to delist the eagle, along with several other species, is partly motivated by supporters trying to defend the Endangered Species Act from concerted, Republican-led attacks in Congress to weaken it.

"The [U.S.] Fish and Wildlife Service denies it, but it's clear they are under pressure to prove the act is working," he says, adding, "To me, saving the act is not the issue. The issue is do we protect the eagle on Chesapeake Bay."

The bay's eagles, which don't migrate as many bald eagles do, can be considered a discrete population, Byrd says, which means the feds could keep bay eagles listed, while delisting those in other areas.

"But they have no plans to do that," he says.

The eagles' situation -- celebrating a comeback with no semblance of a firm plan to sustain it -- is symbolic of a larger problem.

Around the Chesapeake, we are not yet fully accounting for trends, from burgeoning auto use and population growth to shifts in agriculture, that will erode restoration efforts.

You can't applaud how fast you are swimming until you recognize the current you are swimming against.

To comment on the proposed delisting of bald eagles, call 309-793-5800, Ext. 524, before Tuesday.

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