Pigeons were also used experimentally by the coast guard as spotters. They were trained to locate the emergency orange color and would be placed in a plastic pen below a helicopter. The pen had keys which the pigeons could tap when they saw something indicating a direction to the pilot.
The program was canceled due to budget cuts but the science behind it and the preliminary results seem sound.
http://www.uscg.mil/history/articles...SARProject.asp