(Neubronner) showed his camera at international expositions, where he also sold postcards taken by the birds. Additionally, he developed a portable, horse-drawn dovecote, with a darkroom attached to it, which could be moved into proximity of whatever object or area the photographer hoped to capture from on high. These inventions represented a breakthrough at the time, allowing for surveillance with speed and range that was previously impossible. (Whether the cameras would actually capture the desired object, however, depended on luck and the whims of the pigeons.) The technology would soon be adapted for use in wartime—the cameras served as very early precursors to drones—although by the time of the First World War, just a few years later, airplanes were allowing people to do things that only pigeons could have done before.
(Thanks, Bob Pescovitz!)