Damage control

Meera Subramanian reports on current efforts to reduce bat and bird mortality at wind turbine sites. Progress has been made even at the eagle-deadly Altamont Pass.

In Cádiz [in Spain], temporarily shutting down turbines has worked because the biggest threat is to migratory birds, which pass through only occasionally. Similar methods could reduce mortalities along the migratory bottlenecks in Central America, Europe and Asia, says Miguel Ferrer, a conservation biologist at Doñana and a co-author of the Cádiz study.

But that tactic will not work in Altamont Pass, which has both migratory and permanent avian populations. Instead, companies there are making headway by replacing small, ageing turbines with fewer large ones. Choosing sites carefully can help, too. “Raptors do not use the landscape randomly,” explains Doug Bell, wildlife programme manager with the East Bay Regional Park District, which manages parklands and monitors wind farms around Altamont.