Data from: Contrasting drivers of diversification rates on islands and continents across three Passerine families

Rates of diversification vary greatly among taxa. Understanding how
species-specific traits influence speciation rates will help elucidate
mechanisms driving the production and maintenance of biodiversity over
broad spatiotemporal scales. Ecological specialization and range size are
two characteristics thought to predict differences in speciation rates
among clades, yet each mechanism predicts both increases and decreases in
speciation. We estimate a continuous index of specialization using avian
bill morphology. We determine the relative effect of specialization and
range size and shape on speciation rates across 559 species within the
Emberizoidea superfamily, a morphologically diverse clade distributed
across the Americas and associated islands. We find a significant positive
correlation between specialization and speciation rate, and a negative
correlation with range size. Only the effect of specialization persisted
after removing island endemics, suggesting that ecological specialization
is an important driver of diversity across large macroevolutionary scales
and the relative importance of specific drivers may differ on islands and
continents.