Abstract: This invention is concerned with devices for controlling movement of small animals, of the kind commonly known as "Cat Ports". The device is activated by an operating magnet worn by the small animal, which when the animal moves to pass through the device, closes a reed switch. The reed switch is adjustably pre-biased by a positionally adjustable permanent magnet, to afford the reed switch with a desired sensitivity, and a control circuit includes a re-setting coil to return the reed switch to its open position after a predetermined time interval. The device may readily be modified to control movement of animals in either, or both directions, to and from a designated area.