The armed protesters who occupied a remote bird sanctuary in Oregon's high desert earlier this year did so to protest federal land policy, which has been a point of contention in Western states for decades.

On Tuesday opening statements are set to begin in the federal trial of seven protesters, including brothers Ammon and Ryan Bundy, part of a Nevada ranching family embroiled in a long-running dispute over land use.

The defendants are charged with conspiring to impede Interior Department employees from doing their jobs at the Malheur National Wildlife Refuge through intimidation or threats. Five of them are also charged with possession of a firearm in a federal facility.

The takeover started Jan. 2 as a protest against the imprisonment of two Oregon ranchers convicted of setting fires and quickly grew into demands for the U.S. government to turn public lands over to local control.