Adding bird detection systems could protect wind farms from litigation in case of deaths of threatened species.
Just before daybreak, a group of naturalists don parkas to blunt the frosty wind blowing down a narrow canyon in the Tehachapi Mountains north of Los Angeles. They mount spotting scopes and cameras on tripods, and wait.
“Showtime,” one of them whispers at the first rays of light. The silence is broken by thousands of brightly colored birds the size of Christmas ornaments pouring north through the canyon on whooshing wings, just a few yards above ground.
Kern County bird expert Bob Barnes stands spellbound. Peering through binoculars, he says, “They’re following the contours of the canyon like a living river of birds.”
This is Butterbredt Spring, arguably the best place in California to witness the spring migration of birds. Why it attracts so many — tanagers, warblers, orioles, grosbeaks, vireos and flycatchers — is not entirely understood. But something about the topography and its fierce winds has a funneling effect on birds moving over the mountains along the Pacific flyway.
Throughout the Tehachapis, wild and windy places like this have become crucial refuges for songbirds, as well as for critically endangered California condors and federally protected golden eagles. They are also a magnet for wind farms spreading across the region’s cliffs, canyons and ridgelines.
Now, in what has become one of the most critical conservation issues in the state, wind farms are considering using radar units and experimental telemetry systems that they hope will avoid harming birds by identifying incoming species early enough to switch off the massive turbines and then — to minimize costs and maximize profits — turn them back on again as quickly as possible.
“The greatest threat to migrating birds in my lifetime is unfolding in those mountains,” said Jesse Grantham, former California condor coordinator for the U.S. Fish and Wildlife Service. “As for condors, strikes are inevitable. They travel together when a food source appears, so a single turbine blade could take out a lot of them in one swing.”