"On-line" monitoring of jaw movements in the pigeon

A system for the monitoring of jaw movements in the pigeon is described. A Hall-effect device mounted on the pigeon's upper beak is used to sense voltage changes induced by variations in the position of a magnet mounted on the lower beak. Analogue voltage changes are digitized and monitored by a microprocessor. The system produces data comparable to that obtained using high speed cinematography but permits "on-line" measurements of gape and increases the rapidity of data acquisition and analysis. It may be used to monitor beak movements during consumatory (eating, drinking) and conditioned (key-pecking) behaviors.