Blue herons make a home in Sellersville, Pa.

Big birds' arrival signals the start of spring in the wetlands

April 12, 2002|By Peter Sigal | Peter Sigal,KNIGHT RIDDER/TRIBUNE

SELLERSVILLE, Pa. - Like a blast from the Paleocene epoch, the great blue heron's strange, guttural cries echo across the fields, culs-de-sac and townhouses that ring the Quakertown Swamp in central Bucks County, Pa.

"It'll stop you dead in your tracks," said John Matz of Sellersville, who has been an involuntary host to the herons on his property since the mid-1990s.

A hospitable spot

This time of year, the herons have exchanged their solitary hunting lifestyle for the social whirl of a secluded rookery behind Matz's house. Separated by dense underbrush and hip-deep water, they go about the business of building nests, choosing companions, mating, and settling in for the summer to incubate and raise their young.

The swamp has been a hospitable spot, and word appears to be spreading. At first, Matz said, only a few pairs nested there, high in the branches of waterlogged trees. Last year, about 60 pairs called it home, making it the largest rookery in Eastern Pennsylvania, experts say.

Gary Gordon, a resource-protection specialist with Doylestown's Heritage Conservancy, a nonprofit land-preservation organization, called it the "Central Park phenomenon": With development encroaching on all sides, the birds are flocking to the few remaining secluded areas.

It's also likely, Gordon said, that beavers have played a part. The rodents' tireless dam-building has increased the size of the swamp and left more dead trees surrounded by water, where herons prefer to roost in the tallest branches.

81 acres protected

This year, the herons' gathering is a bit more secure from human intrusion. The conservancy and Richland Township have bought - with more than $550,000 in public and private money - 81 acres of the 518-acre wetlands, which harbor 90 other bird species, including the rare Virginia rail and marsh wren. And the county has committed money to buy an easement on the Matz property.

Sharon Yates, the conservancy's vice president of planning, said her group needs to preserve the swamp because federal and state wetlands regulations don't offer enough protection.

Yates described the rules as "just extra hoops to jump through" for developers.

The herons are the stars of the swamp, both for their gangly grace and for what they tell us about the health of the environment, experts say. They are at once highly adaptable - flourishing nearly unchanged for 60 million years from western Alaska to the Galapagos Islands - and extremely sensitive to human intrusion, abandoning colonies if they can't nest in peace.

"They're very particular," said Bruce Peterjohn, a federal wildlife biologist who has written extensively on great blues. "If they have a secure place, and the people in the area don't mind their presence, the herons will do OK."

Time for appreciation

Only recently has Matz, 65, had the time to appreciate the growth of the heron colony on the 18-acre property that he and his wife, Carole, have owned for 32 years. Leukemia has forced him to quit his job as a printer, but the disease has given him time to observe the watery world behind his house.

"It's been bad," he said of his illness, "but it's been good in a way. I've seen so much."

Researchers such as Peterjohn and Katharine C. Parsons, a senior scientist with the Manomet Center in Massachusetts, see great blue herons as the perfect subject for study: As wading birds, they have one foot in the terrestrial world and the other in the aquatic, and their size and tendency to nest in colonies make them easy to track.

"For suburban communities to have such evolutionarily old animals in their midst is fairly exciting," said Parsons, who since 1993 has studied herons on Pea Patch Island in the Delaware River off Wilmington, the East Coast's largest rookery with about 500 pairs.

A thriving heron colony such as the one near Quakertown indicates that the quality of nearby waterways is generally good, she said, because evidence of pollution would quickly show up in the form of thinner eggshells and increased chick mortality.

Herons are not particular about their diet, and travel as much as 20 miles to forage for fish, frogs, mice and snakes. Even backyard koi ponds aren't safe from the lightning strike of a heron's bill, Peterjohn said.

Weeks ago, the early birds began checking in to the swamp, claiming the choicest nesting sites at the colony's center and preparing for the mating game.

"Courtship is a lot more complicated than you might imagine," Peterjohn said. "It's not just putting a few sticks together and off you go."

To catch a female's eye, males grow long plumes on the breast and back - feathers coveted by milliners at the turn of the century - and their bills turn bright yellow-orange.

To seal the deal with the females, who are the nest-builders, males must demonstrate their prowess at gathering sticks and twigs.

Going too far

Sometimes they go too far in their quest to impress.

"I've seen a male come in with a big branch ... you can see the look on [the female's] face, like, what am I going to do with this?" Peterjohn said. "Then, after he leaves, she'll throw it away because she can't use it."

By the end of this month, nests - and relationships - will be built. Males and females collaborate in raising the chicks, which are ready to head out on their own by late July. The adults will leave the rookery, returning to their favorite local waterways to hunt.

In the still heat of August, the swamp will belong to the beavers, wood ducks and deer ticks - at least until next spring, when the herons will gather again to perform their ancient rituals.

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