All guns, traps, nets, seines, fishing tackle, teams, horses, or means of transportation of every nature or description used by any person or persons within the limits of said park when engaged in killing, trapping, ensnaring, taking, or capturing such wild birds, fish, or animals contrary to the provisions of this Act or the rules and regulations promulgated by the Secretary of the Interior, shall be forfeited to the United States and may be seized by the officers in said park and held pending prosecution of any person or persons arrested under the charge of violating the provisions of this Act, and upon conviction under this Act of such person or persons using said guns, traps, nets, seines, fishing tackle, teams, horses, or other means of transportation, such forfeiture shall be adjudicated as a penalty in addition to the other punishment prescribed in this Act. Such forfeited property shall be disposed of and accounted for by and under the authority of the Secretary of the Interior and the proceeds paid into the Treasury of the United States: Provided, That the forfeiture of teams, horses, or other means of transportation shall be in the discretion of the court.