A research helicopter has crashed after an elk it was trying to capture jumped into its tail rotor, authorities in the United States state of Utah reported.

The accident happened as crew tried to drop a net on the animal as the aircraft flew about three metres above ground in a mountainous part of eastern Utah, the Wasatch County Sheriff’s Office’s Jared Rigby said.

The two people on board were not seriously hurt, but the elk died of its injuries Monday afternoon.

The state-contracted Texas-based helicopter crew was trying to capture and sedate the elk and give it a tracking collar to research its movements in the area, about 145 kilometres east of Salt Lake City.

State Division of Wildlife Resources’ Mark Hadley said the crash happened after the crew launched a net to catch the animal, but when that didn’t immediately work the pilot started to slow down so someone could jump out and hobble the elk.

As the helicopter slowed down, the elk collided with the rotor, Mr Hadley said.

State officials will review the incident.

Utah state captures about 1300 animals each winter, almost all using helicopters, and Tuesday’s downing of the helicopter was the first accident of its kind, Mr Rigby said.

The tracking collars help wildlife officials monitor elk migration paths and survival rates.

However, environmental groups have protested against the use of helicopters to monitor wildlife.

The group Wilderness Watch is objecting to a plan to study mountain goats using helicopters in a central-Utah wilderness area, calling the aircraft an “unnecessary intrusion into some of our most treasured lands,” according to local media.

-AP