CHICAGO (CBS) — Project Herd, an experiment that started last year to clear brush at O’Hare International Airport, will return this spring; bringing back a herd of goats, sheep, llamas, and wild burros to get to areas crews can’t reach with lawnmowers or other equipment.

“They had voracious appetites, so they were able to do a very good job, and they’ll be brought back sometime later this spring,” said Karen Pride, spokeswoman for the Chicago Department of Aviation.

WBBM Newsradio’s Kimberly Easton reports the herd, comprised of 25 rescued animals, has a perfect appetite to help clear brush in rough terrain at Chicago O’Hare’s International Airfield.

“There might be hills, or gullies, or those types of areas that it’s a little difficult to get in with equipment and clear that brush, and it’s important we get in there and clear that brush,” Pride said. “There’s 7,000 acres at O’Hare, so there’s plenty of brush that needs to be cleared so that other animals, wildlife, who might be around the airport don’t find nesting areas, or burrowing areas.”

The grazing animals are also a greener, more inexpensive option for clearing brush than typical yard equipment. Officials at Settler’s Pond, the animal rescue group that has provided some of the animals, said they don’t even notice all the planes taking off and landing at O’Hare while they’re grazing.

Pride said keeping the brush low prevents birds and other wildlife from nesting on the airfield. Such wildlife could present a serious hazard to airplanes as they take off and land at O’Hare.

The herd of animals is kept in fenced-off areas of the airport, so there’s no chance of them running onto a runway or taxiway.

Other airports have similar projects, including airfields in San Francisco, Seattle, and Atlanta.

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