The animals were spooked and volunteers there to help manage road jams when the sheep are easily visible from the road watched as they scattered. In some cases it appeared lambs were separated from their mothers in the chaos.
The volunteers, not authorized to hand out citations, approached the group and told them what they were doing was illegal.
"I am sure most people who fly drones have no desire to harm wildlife or endanger our other visitors. Many may not even know that it is illegal to fly a drone here at Zion," Superintendent Jim Milestone said in a statement.
"We hope that by educating the public about the reasons behind the restrictions, we will increase their understanding and compliance and help to protect the park," he said.
Law enforcement rangers in Zion average up to four drone cases each week and there are other reports.
"It seems to have exploded recently. They are getting more affordable and now that you can put a camera on them they are more purposed," said Zion National Park spokesperson Aly Baltrus. "We have had visitor complaints from Angel's Landing and Canyon Overlook. Drones kept buzzing them."
Bighorn are not the only species that officials fear could be impacted by the drones. Although no egg has been spotted it would be in a cliff area difficult to see biologists say a pair of California condors are displaying all the characteristics of a successful nesting.
If there is an egg, it is likely the first in Utah since the birds were reintroduced along the Utah/Arizona border as part of a nonessential experimental population through the Endangered Species Act.
"Condors usually only lay one egg every two years. If we have instances of unmanned vehicles running around stressing out wildlife it could be a significant impact," said Fred Armstrong, chief of natural and cultural resources at Zion.
"We could have situations where birds incubating eggs could be spooked or disturbed and it could cause them to lose interest and abandon the eggs," Armstrong said.
Zion annually closes popular climbing routes in the park near known peregrine falcon nesting areas.
"We don't need this next new element to stress in the environment," Armstrong said.
While it may seem like the perfect way to take unique pictures and video, Baltrus said not even international film crews or the park's search and rescue team are allowed to use drones in Zion. Other national parks adhere to the same policies.
The penalty for using a drone in a national park can be up to six months imprisonment and/or a $5,000 fine. Baltrus said she wasn't sure if any citations have been handed out at Zion.
State wildlife officials say they have seen a troubling increase in the number of people using drones in close proximity to animals.
"Technology opens up things we have never had to deal with before," said Torrey Christopherson, a captain with the Utah Division of Wildlife Resources' law enforcement section. "In the last few months it seems like everybody and their dogs has been going out and buying drones."
Recent drone reports, he said, have come from people concerned that people were using the contraptions to fly over rugged lands looking for antlers shed by deer and elk. In many of those cases the animals were still in the area. Big game animals are sensitive and fragile in the winter months and harassment by people can stress and even kill wildlife.
"Drones are a new challenge for Zion National Park and our mission of resource protection," said wildlife biologist Cassie Waters. "Animals can be injured when attempting to escape or avoid drone activity. Drones can also change the natural behavior of wildlife and lead to unnecessary energy expenditures. This has the potential to affect survival and reproductive success in many species."
DWR director Greg Sheehan said Utah and federal laws prohibit the use of drones to harass or hunt wildlife.
"We are making efforts to make sure people who enjoy photographing or hunting wildlife know that drones cannot be legally used," Sheehan said.
Zion and state wildlife officials say the public should report any apparently illegal use of drones.
Reporter Robert E. Mims contributed to this report.