The use of spatial and local cues for orientation in domestic chicks (Gallus gallus)

Birds have been widely used to study spatial orientation. However, since different birds rely on different types of visual information to find goal locations (such as spatial information from free-standing objects or local cues, i.e. characteristics of a goal location like color and shape), it is important to investigate this aspect in each model species. The aim of the present study was to clarify whether domestic chicks, a ground-living bird and a widely used model for the comparative study of spatial orientation, are able to reorient in relation to free-standing objects and if they preferentially follow local or spatial cues. Furthermore, we also investigated whether monocular eye occlusion influences the ability of chicks to use spatial or local cues. Chicks were trained and tested in a large circular arena with free-standing objects providing relational spatial information, to find food in one of the feeders. We found that dark-incubated male chicks were able to reorient in relation to distinct, free-standing landmarks (Experiment 1), but when local and spatial cues were put in conflict, chicks significantly preferred local cues over spatial cues (Experiment 3). Moreover, while the use of one eye system only was not sufficient to orient by spatial cues (Experiment 2), the preference for local over spatial cues was independent of monocular occlusion (Experiment 4). The results are discussed in relation to our general knowledge of spatial information processing in domestic chicks.