Dozens of blindfolded mountain goats are being flown on slings dangling from helicopters in a US national park.

Rangers at the Olympic National Park in Washington state have embarked on the daring mission in an attempt to return the mammals to their natural habitat and keep visitors safe.

The goats are sedated during the journey and flown to an assembly point, where they are checked by veterinarians.

Image: A similar mission took place last year. Pic: Washington Dept of Fish & Wildlife

They are then loaded into crates on refrigerated trucks and released at six locations in the Cascade Mountains where they belong.

Officials say goats are environmentally damaging to the local area and can be aggressive towards visitors. Last summer, 115 goats were successfully transported back to the alpine habitat.


Image: The animals will be transported in crates to their native North Cascades mountains. Pic: Olympic National Park

In 2010, a hiker died after being gored in the leg by a goat while out walking with his wife and a friend.

The Olympics have few natural salt licks, making it more likely goats there will be attracted to the sweat and urine of hikers, as well as their food.

Park officials hope this year's operation, which will happen over two fortnights in July, will remove around 90% of the mountain goat population.

This means approximately 625 to 675 of the original 725 goats will have been relocated over the two years.

Image: The goats are being dangled from a helicopter in specially-made slings. Pic: Olympic National Park

The non-native mountain goat population at Olympic National Park has more than doubled over the last 12 years, according to a 2016 US Geological Survey report.

About 12 mountain goats were originally released to the Olympic Peninsula between 1925 and 1929, historical records show.

Officials say their priority is to airlift as many mountain goats to safety as they can, but those on steep terrain will be killed if it is too dangerous to reach them.