Navigational ability in the domestic fowl (Gallus gallus domesticus)
Zimmerman PH., Pope SJ., Guilford T., Nicol CJ.
Little is known about the navigational abilities of domestic fowl. The question of how chickens represent and orient in space becomes relevant when they are kept in non-cage systems. Since the sun is known to be the dominant spatial organiser in other diurnal bird species, we started our investigation of the chicken's spatial abilities by subjecting them to a food-searching task with the sun as the only consistent visual cue. In an additional experiment we tried to rule out the use of auditory cues in finding a food reward. Eight ISA Brown chicks were housed in outdoor pens. A separate test arena comprised an open-topped, opaque-sided wooden octagon (2 m wide and 1.5 m high). Eight goal boxes with food pots were attached to each of the arena sides; a wooden barrier inside each goal box prevented the birds from seeing the food pot before entering. After habituation we tested during five daily 5 min trials whether the chicks were able to find food in a systematically allocated goal direction. Food residue in every foot pot controlled for the use of olfactory cues and no external landmark cues were visible. Every day each box was unpredictably moved to a randomly assigned side of the arena and the side to face north was also randomly allocated, to prevent the chicks from using cues other than the sun's position. Circular statistics were used to determine whether birds moved in a non-random direction and if so, if they significantly oriented goalwards. The results showed that seven of the eight birds moved significantly in the goal direction. It seems likely that the chicks used the sun to orient. Due to weather constraints only four chicks received the same treatment on a new location, to rule out the use of auditory cues. Two of these four chicks significantly moved in the goal direction. The results from our experiments show that domestic chicks use spatial memory to orient towards a hidden goal. Moreover, their orientation is most likely to be based on sun cues opening up the possibility that the sun compass may dominate even in this ancestrally predominantly ground-living forest bird. © 2002 Elsevier Science B.V. All rights reserved.