The Ministry of Natural Resources may say the jury is still out but one healthy eagle out of a total of nine nesting pairs in Norfolk County may be unsustainable if it occurs every year and with more wind farms proposed along the north shore of Lake Erie the number of deaths can only increase. Why are we experimenting with an endangered species? ~ Dan Wrightman
The jury is still out on whether wind turbines are a threat to the bald eagle, which continues to make a steady comeback in Ontario, says a ministry of natural resources biologist.
“It’s still a relatively new thing,” Ron Gould of the MNR’s Aylmer office said of the turbines that dot the north shore of Lake Erie, the bird’s main habitat in southern Ontario. “It may take several years to conclude conclusively.”
Thirty years ago, the Ontario bald eagle population was down to two pairs — and they weren’t reproducing — due to widespread pollution that had poisoned the food chain. Especially damaging was the pesticide DDT.
Since then, conservation efforts have helped the bird’s numbers rebound. Today, there are 48 nests in southern Ontario.
In the past few years, green energy efforts have seen dozens of turbines with large rotating propellers go up near the Elgin- Norfolk border where the eagles live and hunt for fish.
So far, monitoring suggests the birds are smart enough to avoid the propeller blades, said Gould.
Only one known eagle fatality has been recorded, he said, a bird found about 40 metres from a windmill in Norfolk County almost exactly one year ago.
The eagle’s body was sent to Bird Studies Canada and then to the MNR. An examination of the carcass showed it had injuries consistent with a sudden impact while toxicology tests indicated it was otherwise healthy, said Gould.
He suggested this particular bird “was maybe a little too careless.”
“My prediction is, if this (turbines) was going to be a significant impact, we’d see more activity at this point,” Gould said. [How many dead bald eagles constitute a problem?]
Jody Allair, a biologist with Bird Studies Canada in Port Rowan who runs an eagle-monitoring program, said it’s hard to tell what kind of effect the turbines are having on the bird’s livelihood.
“Some pairs are successful, some are not,” said Allair. “It’s hard to know why some die and some disappear.”
As part of their studies, Allair and his colleagues climb 30 metres or more to get to eagle nests. There, they place chicks in bags and gently lower them to the ground.
The birds are banded and blood samples are taken from them. Feathers can also be studied to measure the build-up of dangerous metals such as mercury that continue to threaten the birds’ habitat.
Some of the eagles are fitted with transmitters, which look like tiny backpacks on the backs of the birds. This allows their movements to be followed by satellite. The public can also follow the birds on the BSC website.
Norfolk County now has nine nesting pairs, Allair said, and the bird “is increasing in numbers right across Lake Erie.”
Last year was “the best year ever,” for eagle reproduction, he added. Thirty-eight of the 48 nests successfully produced chicks, averaging 1.7 offspring per nest, he said.
The rebound of the bald eagle is important, Allair said, because it indicates “a recovery in the quality of our water.”
Eagles, he noted, are at the top of the food chain. “If something is happening to them, something is going on with rest of the food chain.”