Vulture maps could halt ‘bird-chopper’ threat

The tags generated the equivalent of 31 ‘bird years’ of data, logging vultures’ locations

CRITICALLY endangered bone-eating bearded vultures that live in the Drakensberg now face a new threat in the form of wind farms, which may become “bird-chopping machines” for the rapidly declining birds.

But maps developed by UCT and Ezemvelo KwaZuluNatal Wildlife researchers may just tilt the Lesotho authorities away from allowing two proposed wind farms to go ahead. Ornithologists have described the proposed location of one as being in the “top 1 percent of worst possible sites” to build a wind farm.

The Lesotho authorities have already approved the building of a 42-turbine wind farm near Letseng, but with certain conditions, one being that vulture movements are monitored for a year before the wind farm can be built.

The vulture maps are part of a study published last week in the British Ecological Society’s Journal of Applied Ecology. Senior author Arjun Amar, of UCT, said the maps meant the location of any proposed wind farm could be compared with reliable information about how bearded vultures used the landscape.

“Unfortunately, our maps show that the Letseng wind farm – which has already received approval – is located among the top 1 percent of worst possible sites for juvenile bearded vultures, and could therefore kill considerable numbers of a threatened species whose population is already declining,” Amar said.

To produce the map researchers used information about topography, nesting and feeding sites and data from 21 bearded vultures that had been fitted with solar-powered GPS satellite tags as part of a long-term conservation project. Between 2007 and 2012 the tags generated the equivalent of 31 “bird years” of data, logging the vultures’ location, altitude and speed every hour during daylight.

Researchers compared this with the location of the proposed wind turbines, which showed that there was a high probability of the vultures visiting both proposed wind farms.

Samantha Ralston, manager of Birdlife Africa’s birds and renewable energy section, said yesterday the organisation hoped that the new maps would help tip the scales away from the authorities allowing the wind farms to go ahead.

“The bearded vulture population is declining rapidly. They are particularly prone to colliding with wind turbines because they are quite big birds and also because they have a blind area. They have evolved to look down for their food, so they’re not looking at what’s ahead of them. This map can be a lifeline for them.

“Wind turbines don’t have to be bird-chopping machines and we’re clinging to the hope that this map can be a lifeline and help the Lesotho authorities decide,” Ralston said.

PowerNET Developments, the company that proposes to build the Letseng wind farm, is jointly owned by Aurecon and a Lesotho company.

Pieter Conradie, Aurecon’s business development manager for energy, who is on leave, said he had seen the map briefly last week, adding that the company would use the information it yielded.