16 USC 1332, Definitions, WHB Act, a duly enacted statute.
Paragraph (c) defines “range” as “the amount of land necessary to sustain an existing herd or herds of wild free-roaming horses and burros” that’s “devoted principally but not necessarily exclusively to their welfare.” It stands as it did in 1971.
Paragraph (f), which defined “excess animals” as those “which must be removed from an area in order to preserve and maintain a thriving natural ecological balance and multiple-use relationship” did not appear in the original Act. It was added by PRIA.
CFR 4710.3-2, Wild horse and burro ranges, Part 4700, Subpart 4710, a federal regulation.
Accordingly, herd management areas, a term that did not appear in the original Act, “may also be designated as wild horse or burro ranges to be managed principally, but not necessarily exclusively, for wild horse or burro herds.”
Exhibit A lays down the law. Exhibit B makes it tentative.
Which one prevails? Can a regulation override a statue?