Behavioral and Evolutionary Perspectives on Visual Lateralization in Mating Birds: A Short Systematic Review

Abstract

The division of cognitive processing between the two hemispheres of the brain causes lateralized eye use in various behavioral contexts. Generally, visual lateralization is shared among vertebrates to a greater extent, with little interspecific variation. However, previous studies on the visual lateralization in mating birds have shown surprising heterogeneity. Therefore, this systematic review paper summarized and analyzed them using phylogenetic comparative methods. The review aimed to elucidate why some species used their left eye and others their right to fixate on individuals of the opposite sex, such as mating partners or prospective mates. It was found that passerine and non-passerine species showed opposite eye use for mating, which could have stemmed from the difference in altricial vs. precocial development. However, due to the limited availability of species data, it was impossible to determine whether the passerine group or altricial development was the primary factor. Additionally, unclear visual lateralization was found when studies looked at lek mating species and males who performed courtship. These findings are discussed from both evolutionary and behavioral perspectives. Possible directions for future research have been suggested.

Keywords: courtship; evolution; mating; sexual selection; social cognition; visual lateralization.

Figure 1

Interspecific variation of the visual lateralization in mating context, with left and right eye bias plotted black and white and ambiguous gray, respectively at each tip of the phylogenetic tree (A). Node pie charts in (A) represent the relative probability of left, right, or ambiguous eye bias, inferred by ancestral state reconstruction. Typical examples of the behavioral contexts are given as illustrations, partner viewing in monogamous geese in (B), and courtship display of lekking grouse in (C). Table 1 data are summarized as the number of cases that found clear or unclear lateralization under C (courting), M (mounting) or V (viewing) context in (D).