For the third time in the past month, an owner of an unmanned drone has pled guilty to flying it in Yellowstone National Park, this time over crowds in the Midway Geyser Basin and close to bison.

Park officials announced Friday that Donald Criswell, of Molalla, Oregon, was charged with violating the ban against drones in Yellowstone after he flew the aircraft in the park on August 19. On Thursday he entered a guilty plea to the charge of violating a closure and was fined $1,000, plus court costs.

In late September, Theodorus Van Vliet of the Netherlands entered a guilty plea in connection with an August 2 incident where his unmanned aircraft crashed into Grand Prismatic Spring, a park release added. He was fined $1,000 and ordered to pay more than $2,200 in restitution.

Earlier in September, Andreas Meissner of Germany pled guilty to charges arising from operating an unmanned aircraft which crashed into Yellowstone Lake near the West Thumb Marina back on July 18, the release said. Meissner was sentenced to a one-year ban from the park, was placed on one year of unsupervised probation, and was ordered to pay more than $1,600 in fines and restitution.

All three successfully prosecuted cases arose from well-documented violations of the prohibition of the operation of unmanned aircraft along with other violations of park regulations or impacts to park resources.

The regulation was enacted due to the conflict or impact with a variety of park uses including disturbance of wildlife, impacts or damage to sensitive geothermal areas, and the creation of public safety hazards posed by their unregulated use. The ban is contained in the 2014 update to the Superintendent’s Compendium, which can be found online.

In addition, National Park Service Director Jonathan B. Jarvis signed a policy memorandum in late June that directs superintendents nationwide to prohibit launching, landing, or operating unmanned aircraft on lands and waters administered by the National Park Service.