A secretive, foot-long bird that frequents riverfront cottonwoods and willows could become the next environmental tripwire for the San Pedro River near Sierra Vista.

Proposed federal protection of the declining Western yellow-billed cuckoo is escalating already fierce tensions over river management and the community’s growth. The U.S. Fish and Wildlife Service proposed in late September to list the cuckoo as a threatened species.

Environmentalists hope to parlay federal listing of the cuckoo into tougher restrictions on groundwater pumping and growth near the upper San Pedro in Southeast Arizona, to prevent the river from drying up. They say the cuckoo’s fate depends on that stretch of river’s health because the upper San Pedro has more cuckoos than any other river in Arizona and the West.

Sierra Vista city officials say that they don’t want or need additional, costly environmental restrictions due to the river or protected species, and that they’re already taking steps to reduce pumping. They plan to oppose the cuckoo listing on technical grounds, City Manager Chuck Potucek said.

The Wildlife Service, in its detailed listing proposal, laid out a history of declines of the bird’s population. They’re due in part to human damage to riparian areas with large stands of willow and cottonwood from dams, diversion, groundwater pumping and other forces, the service said.

Today, about 350 to 495 breeding cuckoo pairs live in the Western U.S., and 330 to 530 pairs live in Mexico, the Wildlife Service said. Arizona has the largest known Western cuckoo population in the U.S. — 170 to 250 breeding pairs. That’s 70 to 80 percent fewer than 30 years ago, the service said. The bird’s U.S. range, which once included most Western states, is now concentrated in Arizona, California and New Mexico.

The latest issue

The cuckoo’s proposed protection is the latest in a string of issues for the San Pedro over endangered or threatened species. Over the summer, the Wildlife Service proposed to list another San Pedro denizen, the northern Mexican garter snake, as a threatened species.

Also, the Wildlife Service and Fort Huachuca are rewriting — for the third time — a legally required biological report on how the fort’s presence affects two endangered species living along the San Pedro: the Southwestern willow flycatcher and the Huachuca water umbel. The report will focus on steps to mitigate the impacts of groundwater pumping.

Two earlier biological opinions for the fort were rejected by federal courts. A third was voluntarily withdrawn after the Tucson-based Center for Biological Diversity threatened to sue to have it tossed out. The center is also the group that petitioned the Wildlife Service back in 1998 to list the cuckoo. Now, due to its shaky status, “they have no choice but to list the cuckoo,” said center board Chairman Robin Silver.

“Because the San Pedro is so critical, as a remnant piece of riparian habitat, the city is going to have to grow up and start controlling the imbalance in their water supply between pumping and recharge, when they haven’t done it in the last few decades,” Silver said. “For the city to come in and say they’ll challenge one listing on technical grounds is like a child having a tantrum over something he can’t change,” he said.

Angela Camara, a Fort Huachuca spokeswoman, said the fort is working with the Wildlife Service on a biological assessment of its impact — a less comprehensive document than the biological opinion, which comes later. She declined to discuss the cuckoo because it’s not listed yet.

But as far as Sierra Vista is concerned, “obviously, we would oppose any listing that would increase regulations and costs, legal costs and costs for working on biological assessments for the fort, especially given the budget times we’re in,” city manager Potucek said. “We feel the river is already protected by federal law, and there doesn’t need to be any additional regulatory burden put on the fort.

“We’re constantly looking at a number of different strategies to mitigate impacts on the river, but as far as I know there is no law prohibiting people from moving to Arizona or Sierra Vista,” he said.

The declaration of critical habitat for the cuckoo — a step that is legally required for virtually all federally listed species — would be a more important issue for the city, he said. That’s because it’s easier for the federal government to prove that human activities can damage critical habitat than to prove that a single project will jeopardize a species’ existence.

Genetic challenge

One way the city might challenge the cuckoo listing is on genetic grounds, taking on the Wildlife Service’s view that the Western cuckoo represents a “distinct population segment” from the more common Eastern yellow-billed cuckoo, said Mary Darling, an environmental consultant for Sierra Vista. Matt Johnson, a Northern Arizona ecologist who has extensively studied the cuckoo, said it will be hard to challenge the service’s “pretty solid” finding that the Western cuckoo is genetically distinct from its Eastern counterpart.

“The habitat use by the Eastern and Western birds is quite distinct. The Eastern birds live in orchards and backyards, all kinds of habitat, but the Western birds just use riparian corridors,” Johnson said.

Rather than waste tax dollars to fight the cuckoo listing, the city, Cochise County and others should work together on a plan to protect habitat for all imperiled species in the area, said Tricia Gerrodette of the Huachuca Audubon Society. “Instead of us commenting on and fighting about garter snakes or yellow-billed cuckoos,” she said, “we would look at them all together.”

Contact reporter Tony Davis at tdavis@azstarnet.com or 806-7746. Follow Davis on Twitter@tonydavis987.