Pigeon Trained domestic pigeons are able to return to the home loft if released at a location that they have never visited before and that may be up to 1000 km away. A special breed, called homing pigeons has been developed through selective breeding to carry messages and members of this variety of pigeon are still being used in the sport of pigeon racing and the white release dove ceremony at weddings and funerals. The ability a pigeon has to return home from a strange location necessitates two sorts of information. The first, called "map sense" is their geographic location. The second, "compass sense" is the bearing they need to fly from their new location in order to reach their home. Both of these senses, however, respond to a number of different cues in different situations. The most popular conception of how pigeons are able to do this is that they are able to sense the Earth's magnetic field with tiny magnetic tissues in their head (magnetoception). This is all the more surprising as they are not a migratory species, which is a fact used by some ornithologists to dispute this theory. Another theory is that pigeons have compass sense, which uses the position of the sun, along with an internal clock, to work out direction. However, studies have shown that if magnetic disruption or clock changes disrupt these senses, the pigeon can still manage to get home. The variability in the effects of manipulations to these sense of the pigeons indicates that there is more than one cue on which navigation is based and that map sense appears to rely on a comparison of available cue. Other potential cues used include: