The influence of developmental environment on the evolution of olfactory foraging behaviour in procellariiform seabirds.

The evolutionary origins of foraging behaviour by procellariiform seabirds (petrels, albatrosses and shearwaters) are poorly understood. Moreover, proximate factors affecting foraging ecology, such as the influence of environment on the development of sensory systems, have yet to be addressed. Here, we apply comparative methods based on current procellariiform phylogenies to identify associations between sensory modalities and the developmental environment that may underlie the evolution of complex foraging behaviour. We postulate that, for burrow-nesting species, smell is likely to dominate the sensory world of the developing chick. Alternatively, for ground-nesting species, chicks receive exposure to a range of visual, auditory and olfactory cues. We employ maximum likelihood to test models of correlated trait evolution between nesting habit and olfactory foraging style and to reconstruct the ancestral states of these characters when coded as binary states. Our results suggest that nesting behaviour has evolved in conjunction with foraging style. Based on this analysis, we propose that nesting on the surface was a life-history innovation that opened up a new developmental environment with profound effects on the foraging ecology of procellariiform seabirds.