Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

In birds, large brains are associated with a series of population-level phenomena, including invasion success, species richness, and resilience to population decline. Thus, they appear to open up adaptive opportunities through flexibility in foraging and anti-predator behaviour. The evolutionary pathway leading to large brain size has received less attention than behavioural and ecological correlates. Using a comparative approach, we show that, independent of previously recognized associations with developmental constraints, relative brain size in birds is strongly related to biparental care, pair-bonding, and stable social relationships. We also demonstrate correlated evolution between large relative brain size and altricial development, and that the evolution of both traits is contingent on biparental care. Thus, biparental care facilitates altricial development, which permits the evolution of large relative brain size. Finally, we show that large relative brain size is associated with pair-bond strength, itself a likely consequence of cooperation and negotiation between partners under high levels of parental investment. These analyses provide an evolutionary model for the evolution of and prevalence of biparental care, altricial development, and pair-bonding in birds. © 2010 The Linnean Society of London.

Original publication




Journal article


Biological Journal of the Linnean Society

Publication Date





111 - 123