We’ve seen these pigeons before. This article also has examples of the pictures they took.
Carrier Pigeons Turn Cameramen
SOMETHING entirely new in aerial photography has been developed in Munich, Germany. In place of trained photographers carried aloft in airplanes or observation balloons, camera equipped pigeons are released to fly over the object to be photographed.
The pigeons do not fly at random. Months of training and selection are required before a few birds are chosen for camera work. Then their flights in each direction are timed so that the trainer knows exactly at what time the bird will be over a certain point. It is then a simple matter to time the camera to expose the film at the point desired.