Pigeons use mental map to fly home

Pigeons have a spatial map in their head and possess cognitive abilities, recognising where they are in relation to their loft, a new study has found.

Homing pigeons fly off from an unknown place in unfamiliar territory and still manage to find their way home. Their ability to find their way home has always been fascinating to us humans, researchers said.

Nicole Blaser, a doctoral student in biology at the University of Zurich demonstrated how homing pigeons navigate using a mental map.

Blaser and her colleagues fitted homing pigeons with miniature GPS loggers in order to monitor the birds' flight paths.

Beforehand the researchers trained the pigeons not to obtain food in the home loft, as was normally the case otherwise.

"We fed the pigeons in a second loft around thirty kilometres away, from where they each had to fly back to their home loft," said Blaser.

The scientists then brought the pigeons to a third place unknown to the pigeons in completely unfamiliar territory. This release site was in turn thirty kilometres from the home loft and the food loft.

Natural obstacles obscured visual contact between the release site and the two lofts. One group of the pigeons was allowed to eat until satiated before flying home. The other group was kept hungry before starting off.

"With this arrangement, we wanted to find out whether the hungry pigeons fly first to the home loft and from there to the food loft or whether they are able to fly directly to the food loft," Blaser said.

"As we expected, the satiated pigeons flew directly to the home loft," said Professor Hans-Peter Lipp.

"They already started on course for their loft and only deviated from that course for a short time to make topography-induced detours," said Lipp.

The hungry pigeons behaved quite differently, setting off on course for the food loft from the very beginning and flying directly to that target.

They also flew around topographical obstacles and then immediately adjusted again to their original course. Based on this procedure, Blaser concluded that pigeons can determine their location and their direction of flight relative to the target and can choose between several targets.

They thus have a type of cognitive navigational map in their heads and have cognitive capabilities, researchers said.

The study was published in the Journal of Experimental Biology.