Flight tracks of homing pigeons measured with GPS

Flight paths of homing pigeons were measured with a newly developed recorde r based on GPS. The device consists of a GPS receiver board, a logging faci lity, an antenna, a power supply, a DC-DC converter and a casing. It has a weight of 33 grams and works reliably with a sampling rate of 1 Hz for an o perating time of about three hours, providing time-indexed data on geograph ic positions, ground speed and altitude. The devices are fixed to the birds with a harness, and the data are downloaded when the bird is re-captured. The measured flight paths show many details: for example, initial loops flo wn immediately after release and large detours flown by some pigeons. Three examples of flight paths are presented from a release site 17.3 km northea st of the home loft in Frankfurt. Mean speed in flight, duration of breaks and total length of the flight path were calculated. The pigeons chose diff erent routes and have different individual tendencies to fly loops over the village close to the release site.