New side to extinction story

GREEN ENERGY: BLACK HARRIER'S FATE HANGS ON SPINNING BLADES OF WIND TURBINES

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SILENT CRISIS. BirdLife South Africa estimates that a single wind turbine each year claims the lives of an average of 4.25 birds that fly into its blades, which can reach speeds of up to 280km/h. Pictures: AFP

(AFP)

Powerful gusts shook an observation post perched on a hill at a wind farm in South Africa as two monitors scanned the landscape through binoculars.

The Overberg mountains stretched along the horizon, but the monitors - bundled in scarves - were focused on activity much closer: around a giant wind turbine, a small, dark silhouette had appeared.

"Stop turbine 11, please. Cape vulture," one said into a walkie-talkie. "Stopping turbine 11," came the reply.

Immediately, the blades of the 150m turbine began to slow, coming to a complete stop in less than a minute.

BirdLife South Africa estimates that every year an average 4.25 birds are killed per wind turbine, most often when they fly into blades that can reach speeds of up to 280km/h.

With more than 1 400 turbines operating across South Africa, an estimated 6 000 birds die this way a year, the group says. Ten percent are endangered species.

To mitigate the impact, Excelsior Wind Farm has implemented a shutdown on demand protocol that prioritises six vulnerable species, including the Cape vulture and endangered black harrier.