A quiet reservoir in Los Angeles became the setting for an unusually careful wildlife search in 2025. Biologists were looking for one small endangered songbird, the Least Bell’s Vireo, before a floating solar project could move ahead. They searched the same riparian habitat eight times across the breeding season and found no vireos. What they did find was a much broader picture of life around a reservoir that has been closed to the public for more than two decades, with 60 wildlife species recorded during the surveys.
The work was not a casual bird count. It followed a U.S. Fish and Wildlife Service protocol designed specifically to determine whether Least Bell’s Vireos are present in suitable habitat. The distinction matters because proving that an endangered species is absent is harder than simply failing to see one. A single missed bird can change the conclusion, which is why the federal guidance calls for repeated surveys during the breeding season. At Encino Reservoir, those surveys ultimately became one of the most informative pieces of the environmental review.
