Evolutionary Divergence in Brain Size between Migratory and Resident Birds

• DOI: 10.1371/journal.pone.0009617
• Publication Date: 2010-03-09T18:04:09Z
• Authors: Daniel Sol; Núria Garcia; Andrew Iwaniuk; Katie Davis; Andrew Meade; W. Alice Boyle; Tamás Székely
• Keywords: Divergence (linguistics); Phylogenetic comparative methods

Despite important recent progress in our understanding of brain evolution, controversy remains regarding the evolutionary forces that have driven its enormous diversification size. Here, we report passerine birds, migratory species tend to brains are substantially smaller (relative body size) than those resident species, confirming and generalizing previous studies. Phylogenetic reconstructions based on Bayesian Markov chain methods suggest an scenario which some large brained tropical passerines invaded more seasonal regions evolved behavior migration itself selected for Selection birds may arise from energetic developmental costs associated with a highly mobile life cycle, possibility is supported by path analysis. Nevertheless, fraction (over 68%) correlation between mass distance comes direct effect size, perhaps reflecting cognitive functions become less necessary species. Overall, results highlight importance retrospective analyses identifying selective pressures shaped indicate when it brain, larger not always better.