Western Water News

Over 150,000 Acres of Critical Habitat Designated for the Western Yellow-billed Cuckoo in Arizona

How Audubon made a difference for one of the West's most imperiled birds.


Much has changed since the Western Yellow-billed Cuckoo was listed as a threatened species under the Endangered Species Act in 2014, both scientifically and politically. These changes, both positive and negative, played into last week’s designation of roughly 300,000 acres of critical habitat for the species, which is down nearly 200,000 acres from the habitat originally proposed when the bird was first listed.

Some of the changes added acreage to the designation, like the inclusion of drainages in and around Southern Arizona’s “sky island” mountain ranges where new survey data revealed that Arizona’s cuckoos, much like they do in northern Mexico, make use of oak-dominated grasslands and ephemeral (seasonally flowing) drainages. Other changes removed acreage from the designation and, like the designation itself, are a mixed bag. Some of the exclusions can be attributed to recent troubling changes to the Endangered Species Act that allow for greater consideration of the economic impacts of habitat designation and make it more difficult to designate habitat not currently occupied by the species, even if conservation actions could ultimately return the habitat to suitability and occupancy. Other exclusions were informed by advances in science which narrowed what is considered suitable cuckoo habitat, allowing conservation organizations to focus in on the habitat most essential to the species’ recovery. Additional exclusions were based in equity and tribal sovereignty (all originally designated critical habitat on Tribal Nations was excluded from the final rule).

While this final designation of critical habitat provokes mixed feelings, and while drought, climate change, and uncertainty around water management in the west leave the future of the of the species in question, there is one thing that we’re sure of – the over 100,000 comments submitted by Audubon members and the hundreds of hours that Audubon staff, chapters, students, and other community scientists spent in the field surveying for cuckoos within Arizona’s Important Bird Areas made a lasting, positive impact for the species.

All told, over 150,000 of the approximately 300,000 acres designated by the U.S. Fish and Wildlife Service as critical habitat for the Western Yellow-billed Cuckoo are in Arizona. Read on to learn about some of the sites that our efforts helped protect.

  • Upper Agua Fria River

    Located at the geographic center of the state, the upper Agua Fria River, home to the Agua Fria National Monument Riparian Corridors Important Bird Area, is a well-known stronghold for the Western Yellow-billed Cuckoo. The river and its tributaries support long reaches of healthy Freemont Cottonwood and Goodding’s Willow forest lined with mesquite and juniper/scrub oak communities, habitat long known to be critical to the species. The Agua Fria watershed also supports degraded riparian habitat – stringers of cottonwood and willow with limited surface water separated by large patches of sparse, unsuitable habitat. While it was long thought that this habitat type was not used by Western Yellow-billed Cuckoos, over a decade of surveys led by Audubon Southwest, the Sonoran Audubon Society, the Friends of the Agua Fria National Monument, the Bureau of Land Management, and others turned this old understanding on its head. Repeated detections in this habitat type showed that cuckoos do use these degraded habitats, especially when they are situated between patches of more classically suitable riparian forest. In addition, changes seen in these habitats over years of surveys showed that, in systems like the Agua Fria that still have natural hydrological cycles (periodic scouring floods resulting from summer and winter runoff events), habitat is extremely dynamic and suitable areas can shift from season to season. Thanks to survey efforts on the upper Agua Fria, over 3,000 acres along the river and its tributaries were designated as critical habitat and lessons learned about habitat suitability were able to be applied to other designations across the species’ range.
  • Tonto Creek

    Tonto Creek flows into Theodore Roosevelt Lake in Gila County and now holds nearly 500 acres of critical habitat for the Western Yellow-billed Cuckoo. Surveyed in 2013 by Audubon Southwest and student surveyors recruited through our River Pathways program, Tonto Creek supports stands of healthy riparian forest as well as sparse, Tamarisk-dominated reaches altered by the management of Roosevelt Lake, off-road vehicles, and cattle grazing. Despite these alterations, Tonto Creek still supports significant cuckoo breeding habitat and provides and important migratory corridor for cuckoos travelling further north.
  • Lower San Pedro

    With nearly two thirds of North America’s species making use of the river each year, it’s no secret that the San Pedro is a critical resource to birds. So, it comes as no surprise that over 20,000 acres of critical habitat were designated in its lower watershed. What is a surprise, however, are the types of habitat that the San Pedro River’s cuckoos breed within. Along with world class stands of cottonwood/willow riparian forest, the San Pedro also supports Arizona’s largest remaining intact stand of old growth mesquite bosque, spanning the area between San Manuel and Mammoth. Thanks to surveys conducted in partnership with The Nature Conservancy from 2015 to 2019, it was learned that Western Yellow-billed Cuckoos will breed in great numbers in this habitat type even though it offers little to no true riparian habitat. Not only did this information increase the acreage of critical habitat designated on the Lower San Pedro, it also provided the basis to designate other mesquite-dominated areas within the bird’s range. The habitat designated for the cuckoo on the lower San Pedro River is entirely within the Lower San Pedro River Important Bird Area.
  • Pinto Creek

    Surveyed in 2017 by Audubon Southwest and students recruited through the River Pathways program, Pinto Creek now holds roughly 800 acres of critical habitat for the Western Yellow-billed Cuckoo. The creek, which begins near its confluence with the well-known birding destination Haunted Canyon and flows north into Roosevelt Lake, supports significant stands of Freemont Cottonwood and Goodding’s Willow and, being at slightly higher elevation than much of the cuckoos preferred riparian habitat, also supports stands of Arizona Sycamore and other willow species. Despite ongoing mining in the area and diminishing flow in the creek, this reach supports both breeding habitat and an important migratory pathway for birds moving further north.
  • Upper Verde River

    Partly thanks to surveys conducted by the Prescott Audubon Society since 2015, there are now over 5,000 acres of critical habitat designated for the Western Yellow-billed Cuckoo along the upper Verde River and its tributaries. One significant exclusion within this area is the Arizona Game and Fish Department’s Upper Verde River State Wildlife Area, an Important Bird Area and the primary focus of Prescott Audubon’s survey efforts. While this wildlife area has shown to support significant numbers of breeding Western Yellow-billed Cuckoos, it was determined by the U.S. Fish and Wildlife Service that the benefits of exclusion outweighed the benefits of inclusion. Factors leading to this conclusion included a desire to maintain the ongoing partnership between Audubon Southwest, Prescott Audubon, and the Arizona Game and Fish Department, the continued annual survey effort, and the wildlife area’s stated management priorities which include “riparian habitat, native fish diversity, environmental education, and compatible wildlife oriented recreation”. While critical habitat designation may have added increased protection for the Western Yellow-billed Cuckoo, we’re confident that our ongoing collaborative efforts will succeed in maintaining the suitability of this habitat.
  • Southeastern Arizona’s Sky Islands

    The “sky islands” of Southeastern Arizona are named as such because, jutting high out of the low grasslands and deserts of the region, they provide “islands” of habitat wholly unique from the surrounding area. In these ranges, cuckoos stray from their typical riparian habitat and begin to use a diversity of habitat types including perennial, intermittent, and ephemeral drainages within desert scrub, desert grassland, and oak-dominated Madrean evergreen woodlands. While these habitat types don’t support cuckoos in the majority of the species’ breeding range, the significant monsoon storms emblematic of the region result in a summer “green-up” effect that increases humidity, lowers temperatures, and supports substantial populations of the large insects on which breeding cuckoos depend. Thanks to survey efforts facilitated by Tucson Audubon, the Coronado National Forest, Northern Arizona University, and others, over 22,000 acres of critical habitat were designated across the sky island region.
  • Appleton-Whittell Research Ranch of the National Audubon Society

Situated between the Canelo Hills, the Huachuca Mountains, and the Mustang Mountains, the Appleton-Whittell Research Ranch of the National Audubon Society is home to some of the most pristine oak-dominated grasslands in the state. Just as is seen in the adjacent mountain ranges, summer monsoons result in a boost of productivity on the Research Ranch that leaves it teaming with the large insects – cicadas, grasshoppers, and others – on which breeding Western Yellow-billed Cuckoos depend. Thanks to community science volunteers, critical habitat was designated along several drainages within the Research Ranch as well as within portions of the Canelo Hills that fall within the property. Together, the critical habitat units across which the Research Ranch spans protects over 4,000 acres.

While we are thrilled to be able to celebrate the long overdue designation of critical habitat for the Western Yellow-billed Cuckoo, we are acutely aware that habitat protection alone will not be enough to bring this imperiled species back from the brink. Along with activities and infrastructure like dams, diversions, overgrazing, and off-road vehicle use that damage and modify Arizona’s rivers and streams, the Western Yellow-billed Cuckoo is at increased risk of extinction resulting from the over-allocation of limited water resources, ongoing drought, and climate change. To tackle these issues, we must be at the forefront of confronting climate change and adapting our water management strategies to meet the challenges of a drier future. To do this, we need all of our members and supporters to stand with us - join the Western Rivers Action Network today.


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