Officials with the Tonto National Forest are under orders to change a proposal allowing the use of helicopters to manage Bighorn Sheep.
Environmentalists are applauding the decision.
The ruling by the Southwest Forester means the Tonto National Forest will have to come up with a new plan to catch Bighorns for medical testing and possible relocation.
Arizona Game and Fish wants to do the work with 450 helicopter take offs and landings over a ten year period.
"The question for the Forest Service is does the use of helicopters or landing a helicopter in the wilderness affect the wilderness and the environment and making sure that wilderness is not impacted in any way" said Tonto National Forest spokeswoman Carrie Templin.
She said helicopters might be the best way to capture the Bighorn because they live in areas that are very rugged and steep where there are no roads.
But, conservationists claimed helicopters stress the animals and create a lot of noise.
Forest officials hope to come up with an alternative plan by November.