Hundreds of goats trotted out of a truck Tuesday and bounded into the hillside surrounding the Ronald Reagan Presidential Library in Simi Valley to do what they do best -- eat.

In the process, the herd of nature's lawnmowers add another layer of fire protection around the Southern California landmark, clearing brush that might otherwise provide fuel for wildfires this spring and summer. It's an all-you-can-eat offer that's happily accepted by the goats.

"The goats are great, a wonderful attraction piece for the library, too," said Heather Sumagaysay, of the Ventura County Fire Department. "It's also a reminder that we are talking about wildfire season starting early. A couple weeks ago, we had a 50-acre brush fire. We have had recent rain, but that doesn't mean we don't have a high-risk fire season."

The goats provide what's known as a defensible space around the library, located about 50 miles northwest of downtown Los Angeles in Ventura County. Clearing brush from around the perimeter of the building helps firefighters protect the structure by removing dry fuel for a fire, which can be whipped by winds on the hilltop location and rapidly spread.

If not for the goats, firefighters would have to clear the brush by hand.

The goats, trucked in from a nearby ranch, are watched by herding dogs and a herder, who stays on the property in a trailer. About 300 to 400 goats will tackle the job this year, chewing through brush around the perimeter of the property in something akin to a movable feast.

"They pretty much eat around our entire property," said Melissa Giller, chief marketing officer at the Ronald Reagan Presidential Foundation. "They are within a fenced area, and once that area is 'clean' the fence is moved to the next part of the property."

Authorities make sure no plants that should not be eaten are in the fenced area. The sections also are cleared of wildlife.

The goats are expected to stay on the job for about three weeks. Last year, 1,000 goats were unleashed on the hillside, eating through all the brush in less that one week, Giller said.