The cactus ferruginous pygmy owl is a ferocious predator of birds and small mammals, whose protection as an endangered species under the Endangered Species Act has been the primary impetus for conservation of Sonoran Desert habitats around Tucson, including Pima County’s Sonoran Desert Conservation Plan. The pygmy owl’s protection as an endangered species, however, was removed in 2006 by the Bush Administration based on the faulty premise that pygmy-owl populations are plentiful in Mexico and that their extinction in the United States is insignificant. In March 2007 the Center fought back, filing a petition to list the pygmy owl throughout the Sonoran Desert, including Arizona and northern Sonora, Mexico.

Photo by Robin Silver

Nesting primarily in cavities in saguaro cacti, the tiny pygmy owl has become synonymous with wild Sonoran Desert. With the destruction of its habitat to make way for agriculture and urban sprawl, the pygmy owl has declined to perilously low numbers in Arizona and has sharply declined in Sonora. Since 1993, no more than 41 pygmy owls have been found in Arizona in any year and in recent years fewer than 30 have been documented — far below any definition of a minimum viable population. In particular, rampant urban sprawl has contributed to the near-extirpation of pygmy owls in northwest Tucson, where only one individual was found in 2006.

Although there are more birds in Sonora, they too have been declining sharply. According to researchers at the University of Arizona, pygmy owls in northern Sonora have declined by 26 percent since 2000. Mexico has few habitat protections and literally hundreds of thousands of acres of pygmy-owl habitat have been and are being converted to monocultures of African buffelgrass to support livestock grazing. Massive destruction of habitat and documented declines place the pygmy owl at risk of extinction in Sonora, as well as Arizona.

New era of conservation

The Center for Biological Diversity originally petitioned the U.S. Fish and Wildlife Service to protect the pygmy owl as an endangered species under the Endangered Species Act in 1992, and the species was designated as endangered in Arizona in 1997. Following the listing decision, the Center successfully sued the agency to designate “critical habitat,” which resulted in protection of 732,000 acres in 1999.

Federal Endangered Species Act protections for the pygmy owl initiated a new era of land and wildlife conservation in southern Arizona. Within areas of designated critical habitat, the Fish and Wildlife Service limited development to just 20 percent of most properties. Protection of the pygmy owl also formed the main inspiration for the Sonoran Desert Conservation Plan and Pima County’s “Multiple Species Conservation Plan,” which comprise efforts by the county and others to identify and protect areas in Pima County for the owl and other species.

Protection lost

In response to these protections, developers fought back in 2001 with a lawsuit seeking to overturn the pygmy owl’s listing as an endangered species. Based largely on legal technicalities, the decision to list the pygmy owl in Arizona was sent back to the U.S. Fish and Wildlife Service for further consideration and explanation. The court, however, did not strip the owl of its protected status, nor did it question the science behind the owl’s endangered status. Instead, it narrowly concluded that the Fish and Wildlife Service had not adequately explained its decision that the Arizona population qualified as a “distinct population segment,” which is required for it to be protected as an endangered species.

Despite a number of options for retaining protection for the pygmy owl, the Bush administration cynically seized on the court decision as an excuse to do away entirely with federal protections for the Arizona pygmy-owl population by removing the species from the endangered list in April, 2006. The administration argues that because the pygmy owl is widely distributed in Mexico, Arizona’s owls are insignificant.

Removing the pygmy owl’s protection was vigorously opposed by the Center, Congressman Raul Grijalva (D-AZ; see sidebar), and even the Fish and Wildlife Service’s own biologists, who opposed Bush’s scheme in a 2003 white paper that concluded: “This large scale loss of Sonoran Desert biome communities in northern Sonora places the AZ [population] in a unique and unusual ecological setting” and “The loss of the Arizona population would represent a gap in the range of the taxon and could represent the loss of genetic variability for the taxon as a whole.” Please see “Government Documents” sidebar for a copy of the white paper and other documents relating to the pygmy-owl listing and critical habitat.

The Center’s efforts to regain protection for the pygmy owl

In 2006, the Center joined a suit to overturn removal of protection for the pygmy owl, arguing that when the agency determined that loss of pygmy owls would not result in a significant gap in the species range, they ignored their own biologists, who concluded that Arizona occupies a third of the range of the subspecies and half of the owl’s range in the Sonoran Desert. The Center further argued that Fish and Wildlife has listed many species that are widespread in other countries but endangered in the United States, including the bald eagle, gray wolf, grizzly bear, Canada lynx and others.

On March 15, 2007, the Center filed the petition to protect the pygmy owl again as a threatened or endangered species. The petition requests that the U.S. Fish and Wildlife Service consider protecting either the Sonoran Desert population of pygmy owls, including parts of Sonora; the entire subspecies cactorum, which includes Arizona, Sonora and Sinaloa; or once again the Arizona population. In a detailed discussion of the biology, status and management of the pygmy owl, the petition makes clear that the owl needs protection in Arizona and Mexico and that the agency has a number of options for protection.

The Center has also continued to work for protection of the pygmy owl independent of protection under the Endangered Species Act by funding pygmy-owl research in Mexico and by working with Pima County to develop a strong Sonoran Desert Conservation Plan.

graphic Andrew Rodman ©2002
February 11, 2010
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