18 U.S.C. § 47

(a) Whoever uses an aircraft or a motor vehicle to hunt, for the purpose of capturing or killing, any wild unbranded horse, mare, colt, or burro running at large on any of the public land or ranges shall be fined under this title, or imprisoned not more than six months, or both. (b) Whoever pollutes or causes the pollution of any watering hole on any of the public land or ranges for the purpose of trapping, killing, wounding, or maiming any of the animals referred to in subsection (a) of this section shall be fined under this title, or imprisoned not more than six months, or both. (c) As used in subsection (a) of this section— (1) The term “aircraft” means any contrivance used for flight in the air; and (2) The term “motor vehicle” includes an automobile, automobile truck, automobile wagon, motorcycle, or any other self-propelled vehicle designed for running on land.