YOSEMITE NATIONAL PARK — Ranger Chris Cagle, a lanky six-year veteran of the national park police force, was just following orders when, armed with his Remington 870 pump shotgun, he ventured into the woods last spring after an illegal tom that had settled into the area with a few of his favorite hens.
The resulting demise of the 25-pound male turkey highlighted an unusual policy that has turned the park's protectors into bird hunters. For the last two years, rangers here in California's most famous national park have had a shoot-to-kill order every time they spot the wild version of Thanksgiving's main course.
"We are experiencing disturbing movement of this exotic species into Yosemite," the park's chief wildlife biologist, Steve Thompson, warned in an internal park memo that led to the current turkey eradication program. "Although we have periodically been aware of turkeys along the southwestern boundary of the park, the current invasion is unprecedented in numbers and range."
Aggressive omnivores, turkeys will eat almost anything, from salamanders to acorns, the favorite food of California quail. In the process, they could overrun the quail's habitat and that of other native species.
Benjamin Franklin once proposed the wild turkey as the national symbol, instead of the bald eagle. But here, the wild turkey is on the same hit list as other invasive, nonnative plant and animal species that include star thistle, white-tailed ptarmigan and bullfrogs. Last year, for example, Thompson removed 1,600 bullfrogs from the park.
Thompson and other biologists view nonnative species in much the same way that many people think of rats and cockroaches. The problem in the Yosemite area is that their view is not always shared by custodians of the adjacent Stanislaus and Sierra national forests, where turkeys have been transplanted over the years by the California Department of Fish and Game as a highly prized game bird.
National Park Service officials thought they had checked the birds' advance when, several years ago, they successfully campaigned against a Fish and Game proposal to expand the state turkey-hunting range by introducing a higher-elevation bird, Merriam's wild turkey, on the Sierra's western slopes. That program, Fish and Game spokesman Steve Martarano said Wednesday, has since been put on "indefinite hold."
Until recently, however, Yosemite officials took comfort in the belief that the Rio Grande variety of wild turkeys prevalent in California kept mostly to the lower elevations below Yosemite.
They were proven wrong when the Rio Grande turkeys began moving to higher ground.
The first sightings, noted in the Yosemite Park research library, were in the community of Yosemite West in the southwest corner of the park in 1986.
"Bird height 2-2 1/2 feet, white banding on tail," Fresno resident Milton Irvine wrote in his report of April 2, 1986. "Observed crossing road and proceeding up slope."
Yosemite, most of which lies between 4,000 and 7,000 feet, was considered outside the range of the Rio Grande turkey (Meleagris gallopavo), which is native to the Great Plains states and northern Mexico. Earlier in Yosemite's history, in fact, an ill-advised attempt to implant the birds inside its boundaries failed to take hold.
The Rio Grande birds, first imported to the state from Mexico by ranchers in the late 19th century, were the first wild turkeys in California, although the fossil remains of a turkey-like bird were found in the La Brea Tar Pits.
The Rio Grande wild turkeys spread across the state so rapidly that they are considered a serious nuisance in many areas. Winemakers in the Sonoma and Napa valleys accuse them of feasting on grapes during peak harvest season. Citizens in rural retirement communities next to state parks and forests complain about birds defecating on their parked cars. Bicyclists along Sacramento's American River Trail report attacks from aggressive birds.
Under pressure from citizens fed up with the turkey explosion, the California Department of Fish and Game earlier this month began issuing depredation permits to property owners to kill wild turkeys on their own land. That puts wild turkeys in the same category as coyotes.
Though still relatively rare in Yosemite itself, the turkeys are populous in the neighboring Stanislaus and Sierra national forests and in the lower-lying communities of Oakhurst and Mariposa.
Biologist Thompson said he became alarmed when the birds appeared to be adapting to the conditions inside the park, possibly due to climate changes.
In a policy that has ruffled the feathers of turkey hunters and some full-time park residents, Thomas detailed in an August 2004 memo a program to eliminate the birds either by shooting them or by using a walk-in cage funnel trap.