June 19, 2009 – Biologist James A. Bailey and wife Natalie A. Bailey petitioned to protect the plains bison as threatened or endangered under the Endangered Species Act.
June 16, 2010 – The Center filed a notice of intent to sue the U.S. Fish and Wildlife Service for missing its deadline to respond to the listing petition.
February 23, 2011 – The Service announced its decision that the plains bison didn’t warrant federal protection.
April 14, 2011 – The Center and Western Watersheds Project filed a notice of intent to sue the Service over its decision not to protect the bison.