Commercial wind turbines in northeastern B.C are killing endangered bats

Two species of bats considered federally endangered are being killed by commercial wind turbines in northeastern B.C.

B.C. Environmental Assessment Office documents related to Calgary-based AltaGas's Bear Mountain wind turbines at Dawson Creek show the operation killed an estimated 156 bats and 82 birds in 2010.

More than 40 per cent of the dead bats were either northern myotis or little brown myotis, both assessed last February as endangered by the federal Committee on the Status of Endangered Wildlife in Canada.

Bear Mountain opened in October 2009, connecting to the B.C. power grid as the province's first commercial wind turbine operation.

It features 34 three-megawatt turbine generators; each turbine measures 78 metres to the hub, while the blades measure 40 metres.

AltaGas spokesman Neil Mackie said from Calgary on Monday he didn't want to "split hairs" but noted the two myotis bat species are not technically endangered because the federal government has yet to formally endorse the committee's recommendations.

He added the recommendation to list the bats as endangered was spurred not by wind-turbine deaths but by concerns over the impact of white-nose syndrome, a deadly European fungal disease that is spreading westward across North America.

First discovered in New York state in 2006, the fungus has reached Manitoba and is expected to reach B.C. in a few years, with devastating consequences.

To date, an estimated six million bats have already died from the disease on the continent.

Mackie said the mortality rates at Bear Mountain are about 30 per cent of the North American average for turbines deaths, although he didn't have comparable statistics specific to species considered endangered.

A report for AltaGas by Vancouver's Hemmera environmental consultants suggests the impact of the turbines is "non-significant, low to moderate," but notes that assessment may change once more is known about bat population levels in northeastern B.C.

The report states the carcasses of 53 bats and 23 birds were found during searches between April 20 and Sept. 27, 2010.

Based on an extrapolation accounting for carcasses missed or scavenged, Hemmera estimated a total of 156 bats and 82 birds were killed by the turbines in 2010, a mean of 4.57 bats and 2.41 birds per turbine.

According to a table in the Hemmera report breaking down the dead bats by species there were: 62 silver-haired, 53 little brown myotis, 18 big browns, 15 northern (long-eared) myotis, six eastern reds, and three hoary bats (the table adds up to 157 bats).

Of the birds, none are federally listed as at risk, the report found, although the black-throated green warbler is provincially listed as a species of special concern.