This week, the U.S. Fish and Wildlife Service (USFWS) published its final rule designating critical habitat for the western distinct population segment of the Yellow-billed Cuckoo (Western Yellow-billed Cuckoo) under the Endangered Species Act (ESA). Audubon applauds this final rule—first proposed in 2014 and seven years in the making—for the careful consideration of the habitat needed for continued successful reproduction of this threatened species. In total, approximately 300,000 acres across seven western states—Arizona, California, Colorado, Idaho, New Mexico, Texas, and Utah—are now designated as critical habitat important for the recovery of this species.
As a priority species identified in Audubon’s Water and Birds in the Arid West: Habitats in Decline report, the Western Yellow-billed Cuckoo is present in the western United States mainly during its breeding season from May through September. The cuckoos are about to arrive again. Migrating from Central and South America, its stuttering, croaking calls, audible at a great distance, are often heard on hot, humid afternoons, prompting people to sometimes call this bird the "rain crow."
Sadly, this rule was driven by the severe decline in the population of Western Yellow-billed Cuckoos. Surveys coordinated by various state and federal agencies document fewer than 2,000 breeding pairs of the Western Yellow-billed Cuckoo exist now throughout its range. In fact, the number of breeding pairs in California fell from 15,000 to only 40 in less than 100 years (Hughes 2015). Their steep population decline is linked to the loss of more than 90 percent of their breeding habitat. The USFWS focused on core breeding habitats where the Western Yellow-billed Cuckoo “breeds consistently in relatively high numbers or is breeding in areas which are unique” for this designation and their conservation strategy.
Water diversions, dams, and extended drought impacting southwestern river corridors have wiped out most of the cottonwood and willow forests that once lined the riverbanks—including the Colorado River and its many tributaries. Yellow-billed Cuckoos are still extremely vulnerable to additional habitat loss along streams and rivers.
Arizona remains the most important stronghold for breeding Western Yellow-billed Cuckoos. Although riparian habitats (including mesquite bosques) in Arizona have been significantly reduced, habitats in Arizona remain core to the distinct population segment of the cuckoo and need to be conserved to “enable western yellow-billed cuckoos to produce young that may eventually disperse to other parts of the DPS's range.” For additional information on the recent USFWS decision on the petition to delist the DPS, see my September 2020 article on Western Yellow-billed Cuckoo Remains Federally Protected after Delisting Threat Falls Flat.
Although the acreage designated as critical habitat is reduced by approximately 195,000 acres from what was originally proposed, comments were considered with great care, the best available scientific data was appropriately reviewed, and Tribal sovereignty is respected. No Tribal lands were included in this designation and the USFWS states that they will continue to work on a government-to-government basis with Tribes for conservation of suitable habitat. The ESA authorizes the USFWS to exclude areas from the critical habitat designation if the benefits of excluding the areas outweigh the benefits of including the areas, unless exclusion of those areas would result in extinction of the species.
Some of the excluded lands are sites where partners, like Audubon and other conservation NGOs, have documented commitments to greater conservation measures on their land than would be available through the designation of critical habitat. Collaborative multi-stakeholder cooperative partnerships such as Audubon’s partnership with the International Boundary and Water Commission and Elephant Butte Irrigation District along the Rio Grande in southern New Mexico are prime examples. In the final rule, the USFWS noted Audubon's Kern River Preserve in California is “well known by the public and managing agencies for its value and importance to the Western Yellow-billed Cuckoo.”
Critical habitat designation can help focus management and conservation efforts on these areas of high value for Western Yellow-billed Cuckoo. Audubon recognizes that additional areas besides those identified as critical habitat may be important for this bird’s recovery. Audubon encourages a federally funded, multi-state, coordinated strategy to study and improve conditions for this bird. There is an urgent need for leadership from the USFWS to help address declining and vulnerable species by protecting, creating, restoring, and reconnecting habitat that will contribute to species recovery, adaptation, and resiliency in the face of climate change. Looking forward, the Endangered Species Act would be strengthened by reconsidering recently adopted rules under the Trump Administration that limited critical habitat to just currently occupied habitat, and a requirement that gave greater weight to economic costs against the potential benefits of designating critical habitat.
In this era of decreased river flows – and projections of even less water with climate change impacts – we must ask: how can we improve flows in Southwestern rivers that provide regeneration of riparian habitats to benefit the Western Yellow-billed Cuckoo?