An Eye for a Predator: Lateralization in Birds, with Particular Reference to the Australian Magpie

Abstract

Avian species with their eyes placed laterally on the sides of their head show eye preferences for viewing stimuli at a distance, as determined by the angle of the head adopted when they use the monocular field of vision. Studies of a number of species have revealed that eye preferences are present at the level of the population. Here we were most interested in discussing an apparently general pattern for the left eye to be used to view novel stimuli and stimuli demanding detection and rapid response, as in the case of responding to a predator. We discuss the evidence for this in the domestic chick and some other avian species and then consider lateralized eye use in the Australian magpie tested in its natural environment. We report our recent finding that the playback of a specific "eagle" alarm call to magpies elicits looking up with the left eye and contrast this with the absence of eye/ear preferences in magpies during foraging. We also report that magpies use their left eye to track and locate moving food objects (equivalent to insects). We conclude that magpies have the same pattern of lateralization shown previously in laboratory studies of the domestic chick and we discuss the structural asymmetry of the visual pathways and relate the eye preferences to differences between the hemispheres for processing visual information.