A bird found dead at a Riverside County solar project in May was a Yuma clapper rail, a Federally listed Endangered species. The rail is one of a number of water birds found dead at the site, according to one of the owners of the project. The fatality marks the first reported death of a Federally Endangered bird at a renewable energy generation site in the mainland U.S.
A spokesperson for the Desert Sunlight solar facility near Joshua Tree National Park in Riverside County, confirmed that a rail was found dead on the project site on May 8, further adding that a several dead grebes have also been discovered at the site, and were also reported to relevant agencies for investigation.
The U.S. Fish and Wildlife Service (FWS) wrote an Incidental Take Statement for Desert Sunlight as part of FWS's Biological Opinion on likely impacts of the project, but that statement doesn't mention Yuma clapper rails. If investigation proves the bird died as a result of operation of the project, the death may thus place Desert Sunlight in violation of the Endangered Species Act.
Desert Sunlight's statement pledges that the company will cooperate fully wiith the investigation. Jane Hendron, a press spokesperson for FWS's Carlsbad office, told ReWire that her office didn't yet know the cause of the rail's death, and that plans to minimize future such mortalities would depend on what turns out to have killed the rail.
[UPDATE: Minutes after this piece went live, Hendron informed ReWire that the rail's carcass was too badly decomposed to allow a determination of the cause of death.]
The Yuma clapper rail, which ranges up and down the Colorado River from Mexico to Utah, was listed as Endangered in 1967 under the Endangered Species Preservation Act, a federal law that was a precursor to the 1973 Endangered Species Act. A subspecies of the more widespread clapper rail, numbers of the Yuma clapper rail (Rallus longirostris yumanensis) have declined significantly since then as a result of depletion of its freshwater marsh habitat along the river. Fewer than 1,000 Yuma clapper rails are thought to survive in the United States.
The rails, which are wading birds somewhere between a crow and a chicken in size, subsist on a diet of marsh invertebrates -- mainly crayfish, but also including clams, freshwater shrimp, insects, and occasional fish. The birds prefer mixed stands of vegetation near ponds with stable water levels, and likely probe the waterlogged soil with their long bills to feed.
A century of alteration of the Colorado's flow patterns has drastically reduced the amount of habitat available to the rail, both along the river's length and in what was once a braided network of sloughs and channels in the river's delta. The accidental creation of the Salton Sea a century ago did augment the rail's habiitat, and some still survive in the marshes at its south end.
According to the statement provided by Desert Sunlight's representative Ashley Hudgens, the site's biologists do not believe construction operations contributed to the bird's death. The statement also claims that the rails are not native to the site. That's true, in the strictest sense: there were no open freshwater ponds on the Desert Sunlight project site.
However, Yuma rails do travel between the river and the Salton Sea, and could reasonably be expected to pass the vicinity of the Desert Sunlight project in doing so. Over the last few decades, rails have been spotted as deep into the desert as Harper Lake west of Barstow.
What would entice a water bird like a clapper rail or a grebe to a field of photovoltaic panels deep in the desert? A photo of the Copper Mountain PV facility in Nevada taken by the group Basin and Range Watch offers a suggestion:
PV panels polarize the light they reflect, much like the surface of a body of water. The resemblance of the PV field pictured to a lake is remarkable, even in bright daylight that reveals the technological underpinnings of the site. For night-flying birds, especially on nights when a new or crescent moon doesn't provide much light, all the birds would have to go on would be the reflection of the stars in the PV panels. A large PV project would seem to offer an oasis for water birds in the desert, but coming in for a landing on such a "lake" could well prove routinely fatal, either at the moment of impact or after a disabled bird wanders off into the desert.
ReWire has heard of other reports of waterfowl injuries at photovoltaic facilities, and we're working to determine the extent of the phenomenon. We'll keep you updated as we learn more. If it turns out that Desert Sunlight is attracting water birds due to polarized reflections from its panels, that raises the question of how FWS will approach minimizing similar risk from the proposed McCoy and Blythe photovoltaic projects, which together might offer as much as 15 square miles of fake "lake" to unwary water birds, less than 15 miles from the Colorado River.