Federal snipers firing from helicopters killed 70 feral swine along a Colorado River wildlife refuge covering 3,500 acres in western Arizona and southeastern California. The campaign to eradicate the non-native pigs was completed in less than half the two week period envisioned when the extermination effort began February 20.

“For this operation to to take only three and a half days shows the expert skill of USDA personnel,” said Richard Meyers, Manager of the Havasu National Wildlife Refuge. “These swine live in areas of the Refuge that have thick, dense vegetation that can be nearly impossible for a person to trudge through.”

The U.S. Fish and Wildlife Service said the swine are known to represent a public safety threat for carrying a number of diseases and that they are very destructive to Refuge habitat. The agency said another 100 feral swine were eradicated by the USDA during disease monitoring last year and that others were killed in wildfires the two preceding years.

A news release said staff will continue monitoring the refuge in an effort to maintain the feral swine population at zero.