Homing pigeons don't have the luxury of GPS or sat navs for guidance as they fly, yet release them far away from their home loft and they will quickly and efficiently find their way home. Their astonishing navigation skills have long intrigued scientists, who believe that they use a map-and-compass approach when homing. This involves the pigeons first determining their geographical location using a cognitive map and then using compasses, such as landmarks or celestial cues, to keep them on the right bearing on their way home. While most people assume that pigeons have these cognitive maps, Nicole Blaser, a PhD student from the University of Zürich, Switzerland, realised no one had really tested the idea, so with help from her colleagues and supervisor Hans-Peter Lipp, Blaser began her study (p. 3123).
To test their cognitive map skills, the pigeons were given the option of homing to either home or food loft. However, Blaser had to first train the birds to recognise the food loft. She began ferrying them by car to be fed only at the food loft. After they had adjusted to the food loft, she started releasing them along the beeline between the home and food lofts. Slowly, she incrementally increased the distance from the food loft until the birds could efficiently fly to the food loft from their home loft.
After training her pigeons, Blaser then took them to a novel release site equidistant from the two lofts. Half the pigeons were fed at the release site while the other half remained hungry. Once released, all the satiated pigeons flew off in the direction of their home lofts and all famished birds hungrily headed off towards the food loft. When the team repeated the experiment at new site in Italy, using GPS trackers to map the pigeons' aeronautical journeys, they found that all those heading towards their food loft never detoured via the home loft, which indicates that the cognitive map isn't centred around their home loft and the pigeons can head directly to their goals. The pigeons know their geographical position in relation to targets and will use this map to choose the appropriate bearing for their needs.