GPS dataloggers have beeen extensively used for pigeons.
Mostly for reasearch but also for recreative use in race pigeons.
GPS are fitted very easily on pigeons by attaching it with a velcro strip on the back, Pigeons are carrying plasticine dummies (see photo) all the time when in the aviary and when in free flight. Then, the dummy is replaced with the GPS datalogger just prior to release.

GPS were used for the realisation of a  movie on race pigeons realised by one of the director of “birds in migrations” in which pigeons were tracked in several races between France and Belgium (one was the mitical race from Bourges with 180.000 pigeons released).

This and another movie by the same team are available at: www.colombophiliefr.com

GPS data can be edited by a variety of software for geographical analysis.
Here you can view an example of the tracks recorded in a study area in central Italy

Click here to view a full size version


Pubblications:
How the viewing of familiar landscapes prior to release allows pigeons to home faster: evidence from GPS tracking
Pigeon Homing along Highways and Exits
A GPS Logger and Software for Analysis of Homing in Pigeons and Small Mammals
Miniature Neurologgers for Flying Pigeons: Multichannel EEG and Action and Field Potentials in Combination With GPS Recording