Exo K.M., Scheiffarth G. & Haesihus U. (1996) The application of motion sensitive transmitters to record activity and foraging patterns of Oystercatchers Haematopus ostralegus. ARDEA 84 (A): 29-38

Time budgets are a fundamental tool in ecological research. The paper describes (a) a radiotelemetry system to monitor and quantify activity patterns in the foraging behaviour of free-living Oystercatchers, using mercury switches, and (b) how to analyse such telemetric activity data. The radiotelemetry system enables the entire daily patterns of different activities to be measured automatically. However, activity data recorded by radiotelemetry can be interpreted only if the pulse rate patterns characterizing different activities in each individual bird are known. Therefore, it is necessary to calibrate each transmitter by visual observations on each bird studied. After a transmitter had been calibrated, the system proved highly reliable for continuous long-term monitoring. The system overcomes the limitations of visual observations, and makes more comprehensive and complete data sets available than can visual observations alone. The system was developed to analyse time budgets in Oystercatchers, but the system can be easily modified to study other species.