Keeping common wildlife common the goal with the great blue heron

Posted on: August 4, 2017 | Bob Frye | Comments

They’re the exception to the rule.

Four species of heron call Pennsylvania home. Three are in trouble. The great egret, yellow-crowned night heron and black-crowned night heron are all listed as state endangered species.

Then there’s the great blue heron, familiar to anglers and paddlers who prowl creeks and backwaters everywhere.

It is, by all indications, doing relatively well, said Patti Barber, endangered species biologist for the Pennsylvania Game Commission.

She doesn’t have any numbers to quantify that just yet.

The commission – using staff and volunteers, who made up a big part of the effort – conducted a blue heron nest colony survey this past spring. It was the first such survey in five years.

Results aren’t yet fully tabulated.

“But they do look pretty promising,” Barber said. “A fair number of our sites had increased numbers of birds in them.”

The survey also turned up a few previously unknown nesting sites.

That doesn’t always equate to more birds overall, she cautioned. Herons nest in colonies, or groups, for the sake of protection. More birds on more nests means more eyes to look out for predators, among other things, Barber said.

The largest known colony in the previous survey was found in Crawford County. It consisted of hundreds of nests.

But if predators become too numerous of human development encroaches, herons aren’t afraid to move.

“They don’t have the same site fidelity that some of our other birds do. They’re more adaptable than some,” she said.

That may be why they at the very least continue to hold their own, she said.

“In our ever-changing world, that might be a good thing for them,” Barber added

Great blues are one of Pennsylvania’s largest birds, at least by height and length. A typical adult will weigh just five to six pounds, but will stand up to 48 inches tall and can have a wingspan of up to 79 inches.

“They’re largely all legs and neck, an adaptation that allows them to wade into deeper water and still find food,” Barber said.

They sustain that gangly body by being flexible opportunists.

Patricia Leonard of the Cornell Lab of Ornithology pointed to the description of the birds’ life history at – a good resource, with recordings of what herons sound like, and videos of them in action, among other things – as an example.

The site says they typically slowly stalk prey like fish, reptiles and amphibians in shallow water. They then strike with lightning quickness using their long necks.

They’ll take other prey, too, though, Barber said.

“What they’ll also do, and I’ve seen this, is you’ll see them in a field. They’ll actually go mousing,” Barber said. “They’ll catch small mammals if they can.

“They will eat whatever’s small enough to go down their throat and that they can subdue. That’s the only limitation.”

Still, they, like many species of wildlife, face challenges.

Great blue herons will sometimes overwinter in the state, if enough open water remains, she said. If things freeze, they’ll make the perilous migration south, traveling sometimes as far as the northern extremes of South America.

The hope, of course, is that no matter how or where they travel, they’ll continue to do well here and across their range, which extends across virtually the entire continent.

But the commission wants to be ready if that changes.

“That’s really the goal of our wildlife action plans, to monitor these species while they’re still common and be able to know what’s going on so we can help them. If we can identify problems early, a lot of times we can address them pretty quickly,” Barber said.

“Right now, great blue herons are definitely doing a little better than some. But they’re still susceptible to disturbances at their roost sites. That’s why we want to keep tabs on them.”

A tale of what’s possible

Why spend much time paying attention to wildlife species that are common and, apparently, doing well?

Because of the passenger pigeon.

It was once the most common bird in North America, said Bill Williams, information and education supervisor in the Game Commission’s northeast region office. Estimates are that there were five to six billion of the birds as late as the 1860s.

They traveled across Eastern deciduous forests in monstrous flocks.

One biologist in Kentucky estimated a single group at 2.2 million birds. John James Audubon reported seeing one that “darkened the sky” for three days straight. Also Leopold wrote that to see one go by was to witness “a biological storm.”

And then, suddenly, they were gone.

The last know wild passenger pigeon was killed in 1902. The last pigeon ever, a female named Martha that lived in the Cincinnati Zoo, died on Sept. 14, 1914.

“What we’ve learned is that if you don’t conserve wildlife when it’s common, you can lose it,” Williams said.

Passenger pigeons were about two to three times the size of mourning doves and built for speed. They could travel 60 miles per hour for long distances.

They were gorgeous, too. Males had slate blue heads, metallic gold and violet sides and reddish brown throats and bellies.

A number of things did them in.

Though long-lived, they typically only produced one egg a year, Williams said. They were predictable in where they would be and when. And – initially with Native Americans, later with European pioneers and still after with the residents of America’s first big cities – they tasted good.

Pigeons sold for less than a penny each. Yet “pigeoners” collected by the millions, Williams said. That was for personal use and for sale in markets. Consumers ate their flesh and used their fat like shortening.

With no hunting seasons to limit harvest, the birds were doomed. That was especially true once new technologies debuted, Williams said.

He called railroads and telegraph lines the “one-two punch” that finally brought about the passenger pigeons’ end. Railroads made it possible for people to get to roost sites easily, and the telegraph lines spread the word of where they were and when.

The birds couldn’t take the pressure and disappeared into oblivion.

A wildlife spectacle unlike any other disappeared forever.

“There’s really nothing today that can compare to this bird species,” Williams said.

Bob Frye is the editor. Reach him at 412-838-5148 or See other stories, blogs, videos and more at

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