Data from: Larger brains spur species diversification in birds

Evidence is accumulating that species traits can spur their evolutionary
diversification through by influencing niche shifts, range expansions, and
extinction risk. Previous work has shown that larger brains (relative to
body size) facilitate niche shifts and range expansions by enhancing
behavioral plasticity but whether larger brains also promote evolutionary
diversification is currently backed by insufficient evidence. We addressed
this gap by combining a dataset for >1900 avian species worldwide
with estimates of diversification rates based on two conceptually
different phylogenetic-based approaches. We found consistent evidence that
lineages with larger brains (relative to body size) have diversified
faster than lineages with relatively smaller brains. The best supported
trait-dependent model suggest that brain size primarily affects
diversification rates by increasing speciation rather than decreasing
extinction rates. In addition, wee found that the effect of relatively
brain size on species-level diversification rate is additive to the effect
of other intrinsic and extrinsic factors. Altogether, our results
highlight the importance of brain size as an important factor in
evolution, and reinforce the view that intrinsic features of species have
the potential to influence the pace of evolution.