BILLINGS, Mont. (AP) — Western lawmakers are seeking to elevate the plains bison to a status similar to that of the iconic bald eagle with legislation to declare the burly animal America's "national mammal." Bison advocates launched a "vote bison" public relations campaign Friday to coincide with the bill. The National Bison Legacy Act introduced in the Senate is backed by lawmakers from Wyoming, Colorado, Nebraska, Kansas, New Mexico, the Dakotas and Rhode Island. The largely symbolic measure would provide no added protections for the estimated 20,000 wild bison in North America. Tens of millions of bison, also known as buffalo, once roamed most of North America. Overhunting reduced the population to about 1,000 animals by the beginning of the 20th century.