For years, large numbers of birds of prey have been killed by turbines at Altamonte Pass, California and on Spanish mountain ridges. This was always attributed to tower design and above-ground wiring. Not so, say British ornithologists. It’s the way birds see.
We’re used to looking straight ahead, but birds are more likely to look sideways, above and behind the head. This provides a wider field of view – important for hunting and detecting predators – but it reduces forward vision. Even the peregrine falcon, so sharp-eyed it can spot and catch other birds on the wing, relies mainly on side vision to see its prey, switching to forward vision only at close range.
Prof. Graham Martin, an ornithologist at the University of Birmingham has been studying raptor vision with Dr. Steven Portugal of the Royal Veterinary College and Campbell Murn from the Hawk Conservancy Trust in Hampshire, UK. They measured the visual fields of griffon vultures and African white-backed vultures. “I used the same device that an optician would use when you get an eye test,” he says.
The vultures have large fields of vision to give them a comprehensive look at the ground ahead and the sky on either side. This allows them to scan for food and watch the other vultures in the flock. But as the birds fly, they tilt their heads downwards and the space directly in front of them becomes a blind area.
This is a real problem when humans erect large objects in the vultures’ way. “Across Africa and southern Europe, vultures have become frequent casualties of collisions with wind farms,” says Portugal. “It’s an innate behavioural trait that is causing the problem. The speed of the rotating blade doesn’t help.”
This means making wind turbines more conspicuous won’t reduce collisions. “You can paint them with bright stripes or hang things off them, but that won’t be effective. You’ve got to keep the birds and the turbines apart.”
Both the Altamonte Pass industrial wind turbines and the ones on Spanish ridges are built on migratory pathways where millions of birds funnel through a north-south corridor. Does that sound familiar? It’s obvious from the high bird kill on Wolfe Island that placing industrial wind turbines on this area’s migration flyway is disastrous to birds. The new study helps us understand why.
Prince Edward County, on that same flyway as Wolfe Island, is the wrong place to build industrial wind turbines. That’s what science is telling us. The proof is in.
Prince Edward County Field Naturalists report a recent tour of the proposed site for the White Pines Project industrial wind turbines shows road work already under way.
“This premature road construction before any public consultation has taken place is abhorrent,” says Cheryl Anderson, of PECFN. “Does WPD think that the citizens of Prince Edward County are just going to sit idly by while the South Shore IBA is attacked in this fashion?”
The 29-turbine site is to be developed in South Marysburgh and Athol by WPD Canada. Company officials will set up display panels and answer questions Thursday, March 22 from 5:30-8 p.m. at Prince Edward Collegiate Institute.
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