JACKSON (AP) - Bright lights and firecracker-like blasts are deterring wolves from attacking cattle in Grand Teton National Park, officials said.

Ranchers have not reported any depredations since wolves from the Teton Pack killed a 400-pound calf Aug. 10 in the park, said Mike Jimenez, the federal wolf recovery project leader for Wyoming.

The attack was the first recorded in the park since the wolf pack took up residence at Grand Teton in 1999.

After learning of the incident, the U.S. Fish and Wildlife Service assigned a crew to spend three nights with the cattle. Each time wolves approached the herd, "we would shine a light and fire cracker shells to scare them away or make them uncomfortable," Jimenez said.

Although the crew had to chase the wolves away several times, no depredations occurred.

The methods sometimes work in the short term but do not have as much success with chronic problems, he said. But for now, the techniques are paying off.

"(The wolves) have gone back to their regular pattern, so hopefully they don't go back to bothering the cattle," Jimenez said.

This summer, the Teton Pack has hunted elk primarily along the Snake River. But to reach the elk from the pack's rendezvous site on the eastern edge of the park, the wolves must cross pastures where cattle graze.

Franz Camenzind, executive director of the Jackson Hole Conservation Alliance, said the grazing allotment is an unnecessary temptation for wolves that ought to be phased out.

"It's like having a field trip every day with your third-graders, right through the middle of the candy store, and expecting them not to get addicted to candy," he said.

The grazing permit, issued to the Porter, Lockhart and Gill families, originally expired in 1995.

Congress passed a law in 1997 to extend the permit and that of another ranching family while authorizing a study of whether grazing helps preserve open space in Jackson Hole by helping ranchers stay financially afloat, which can discourage them from subdividing their property.

The study was completed in 2001, and the National Park Service and Department of the Interior are working to draft a recommendation to Congress on whether grazing in Grand Teton should continue.

Until Congress acts, the Park Service is legally obligated to allow grazing, park spokeswoman Joan Anzelmo said.

Grand Teton officials have asked the ranch families to assign a rider to stay with the cattle overnight to discourage depredations.

"We're working closely with the grazers to mitigate any extra temptation for those wolves," she said. "So far, these things have been successful."