. . . the special police appointed by this act are authorized to arrest any person or persons who may be discovered in the act of hunting or shooting crippled ducks, or in purloining ducks that have been killed by other persons having a proper license to shoot, as well as other persons violating the provisions of this section, and upon conviction thereof before any justice of the peace of Cecil or Harford Counties, the license of such persons or persons shall be revoked, and such persons or persons, whether licensed or not, shall be fined not less than twenty dollars for each offense, and shall forfeit the boat and gun or guns, and material so employed in violation of the provisions of this section, which boat and gun or guns, and material shall be sold, and the proceeds of such fine and sale, after the costs of prosecution have been paid, shall go to the officer or officers making the arrest. . .