Thursday, April 24, 2014
WELLS — One of the most prevalent of Maine’s wetland birds has gone missing, but a biologist is confident citizen scientists will answer the call to help find out why.
The Heron Observation Network, created in 2009 by the state, has helped organize a statewide group of volunteers that will become particularly important in the next year. The result of their work has offered evidence that great blue herons are in decline here.
At a York County Audubon presentation last week, state bird biologist Danielle D’Auria explained the theories, the data gathered and the significant work ahead to help Maine’s heron populations, particularly the star of this community, the great blue heron.
Since 2009 there has been an effort to survey herons after a wealth of data on bald eagles began to point to a decline in the heron populations in Maine.
As bald eagle data was gathered over time, heron counts were added. Piggy-backing on the bald eagle study, the heron data began to show a surprising drop in the numbers of this prolific bird, D’Auria said.
In 1983, there were 20 colonies and 1,208 pairs compared to 644 pairs in 14 colonies along the coast. Meanwhile bald eagles have been on the rebound with just 16 pairs counted along the coast in 1983 and 50 in 1995, according to D’Auria.
As a result great blue herons were listed as a species of special concern by IFW.
“There is a big hole in what we know. We decided in 2009 to take a statewide census,” D’Auria said.
Many are familiar with the Christmas Bird Count, the worldwide volunteer effort in December to count bird species, which has given National Audubon a remarkable bank of data. In Maine, use of volunteer citizen scientists has gained popularity among many groups.
Maine Audubon, IFW, Trout Unlimited and other groups have recruited volunteers in recent years to start annual counts on critters such as frogs, brook trout, owls, bats and now herons.
In 2009, data was gathered by volunteers looking at heron nesting sites for the first time.
Along the coast, biologists found little more than 400, a further drop from the 600 counted in 1995 in the eagle study.
However, as with so many species, there are huge gaps in what’s known about the heron.
“Our birds don’t winter here,” D’Auria said. “We don’t know where they go. Banding is a hard thing to do with herons. A banding effort in the 1940s showed some going as far as Cuba, but probably not all of them go there. They just need to be where there is no ice.”
What biologists do know is Maine amounts to the ideal breeding ground for great blue herons.
“Habitat is not the limiting factor, given Maine is 95 percent forested. But the colonies in the upland pines are harder to see,” D’Auria said.
They also know great blue herons hold a special place in the public’s consciousness.
D’Auria said an indicator of the bird’s longstanding presence among us is its place in Greek mythology, as a messenger, and among the Egyptian writings, where it was called Bennu or a deity related to the sun god. The Bennu bird was a self-created bird believed to have a hand in creating the world.
Interest in learning about its possible decline is more than a concern for a pretty bird, D’Auria pointed out Tuesday.
“They’re carnivorous, so they are high up on the food chain. They can be a good indicator of wetland health. So it’s good to keep a watch on them (and their numbers),” she said.
However, the data from the Heron Network will do two things: offer a rough sketch of what might be happening, and, more importantly, log volunteer efforts that IFW can count toward its efforts in studying herons, and help get matching federal funds for the heron study.
By 2015, D’Auria said enough money should be raised to conduct a comprehensive aerial study to really learn about these birds who have been with us since the beginnings of civilization.
“It’s challenging because we don’t have complete data. But we’re working toward a population estimate. By 2015, we should be able to get a true statewide population estimate. I’m pretty excited about that,” D’Auria said.
Deirdre Fleming can be reached at 791-6452 or at: