Plastic Owls Proposed as Bird Safety Measure at Large Solar Project

Evidence as to the effectiveness of plastic owls in deterring birds | Photo: Darwin Bell/Flickr/Creative Commons License

The proponents of a large solar power project being considered for the California desert have suggested that they can frighten birds away from their facility effectively enough to lower the risk of wildlife injuries to acceptable levels, and they're suggesting plastic owls as part of their solution.

The suggestion came as part of the project proponent's testimony in a hearing held Thursday by the California Energy Commission concerning the proposed Palen Solar Electric Generating System, which would occupy just under 4,000 acres of open desert near Interstate 10 in Riverside County west of Blythe.

As evidence mounts that the project's mirrors and concentrated solar energy may pose risks to wild birds, Palen Solar Holdings (PSH), the joint venture backing the project, has proposed a plan to reduce bird injuries that includes what PSH calls "passive or automated visual deterrence techniques." One of those techniques, mentioned prominently in a slide show PSH provided to the CEC: plastic owls.

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The Adaptive Management Plan offered by PSH also includes making sure birds can neither nest nor perch on the project's structures, harassing birds from the site with loud noises including gunshots, chasing birds away with off-road vehicles, trained dogs, and remote-controlled aircraft, and even using water cannons or full-sized airplanes to haze the birds.

Other methods included in PSH's passive visual deterrence plans include iridescent streamers and kites shaped like birds of prey.

A page from PSH's Adaptive Management Plan for avian wildlife | Image: BrightSource Energy via CEC

PSH is a joint venture of BrightSource Energy and Abengoa convened to build the 500-megawatt project, which would generate power by aiming tens of thousands of mirrored heliostats at boilers atop two 750-foot towers. The technology puts birds at risk of collision with the mirrors, and burn injuries from the concentrated "solar flux" near the boilers.

PSH staff admit in the testimony provided to CEC that visual deterrence methods have a drawback: in the words of the PSH slideshow, such methods are "initially effective, but subject to rapid habituation."

Meaning that birds get used to the owls unless you move them around a lot.

More data | Photo: Jim Sheaffer/Flickr/Creative Commons License

As it happens, I had a retail job some decades ago which involved selling wildlife deterrents, including plastic owls. It was not at all uncommon for unhappy customers to return those owls some weeks after purchase, often encrusted with the evidence that their local birds had been not in the slightest bit deterred.

To be fair to Palen Solar Holdings, it's incredibly difficult to keep birds away from a large area without completely enclosing it. PSH admits that passive visual deterrence will likely only be effective against large flocks of migrating birds passing through the area for too short a time to get used to the owls and flags and streamers.

The longer-term strategies may actually be cause for greater concern. Loud noise-makers, increased air traffic, use of water cannons, and trained dogs may well pose significant risk to other wildlife in the area, not to mention adding to the overall industrial character the plant will impose on the east end of the Chuckwalla Valley.

Thursday's hearing resulted in many pages of documents available to the public: ReWire will report on other contents of interest on Monday.

About the Author

Chris Clarke is a natural history writer and environmental journalist currently at work on a book about the Joshua tree. He lives in Joshua Tree.
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