ECOLOGY/EVOLUTION

Thinking About Birds

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Science  01 Oct 2004:
Vol. 306, Issue 5693, pp. 21
DOI: 10.1126/science.306.5693.21a

Evolutionary biology has benefited enormously in the past two decades from the application of the life-history approach, which views organisms in the context of conflicts resulting from the allocation of resources to growth, reproduction, foraging, predator avoidance, etc. Cognition is rarely considered in this context; however, if cognition is of benefit to and imposes costs on the individual, then resources devoted to cognitive function might be expected to trade off against other life-history parameters.

Ricklefs shows that, for birds, the relation of brain mass to body mass and that between egg mass and incubation period may both be indicative of the potential links between cognition and life history. For example, taxonomic groups such as parrots, owls, and corvids, which have complex social or foraging behaviors, have higher than average brain-to-body mass ratios, whereas pigeons, which are not renowned for their behavioral sophistication, rank lower than average. Long incubation periods and postnatal development tend to be associated with these same groups and also with raptors and pelagic seabirds; these birds confront some of the greatest challenges in learning social or foraging skills. Ricklefs argues that behavior based on accumulated experience can logically be treated as an integral part of bird life history and hence sets the stage for an exploration of the underlying mechanisms. — AMS

Wilson Bull. 116, 119 (2004).

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