Phoenix, ArizonaIn a desert valley outside Tucson lives a fierce predator that weighs less than a deck of cards. The cactus ferruginous pygmy owl, which nests in the Sonoran Desert’s iconic saguaro cactus, routinely takes down prey twice its size. “It’s the most ferocious raptor I’ve ever worked with,” says biologist Michael Ingraldi with the Arizona Game and Fish Department.

But this six-inch-tall bird with its piercing golden stare is no match for threats such as urban sprawl, border wall construction, and climate change that are closing in from all sides, jeopardizing its existence in the most northern part of its range.

A subspecies of the widespread ferruginous pygmy owl, the cactus ferruginous pygmy owl is limited to