The vacant cottages and boarded-up buildings taken over by the cats must to be razed to make way for what is to become the county's first "green" building, the Los Angeles Times reported Monday.

Before construction can start at the site just south of the Rancho Los Amigos National Rehabilitation Center, something must be done about the cats.

The never-tamed offspring of abandoned or lost pets are usually too wild to be adopted as house pets but euthanizing them would be both time-consuming and expensive, The Times said.

Efforts are currently under way to relocate the cats.

Los Angeles County says it is sending hundreds of fliers advertising an initiative called Project Barn Cat.

"We're trying to get these cats placed in local barns and equestrian environments, where hay storage makes rats a problem," says Michelle Roache, deputy director of the county's Department of Animal Services and Control.