What can birds tell us about Darwins mystery of mysteries, the origin of species?
JT: One upshot of the popularity of birds is that we know lots about them, and this simple fact accentuates their importance for studies of speciation. We have at our disposal more information about species limits, global ranges, ecological niches, and life-history strategies for birds than for any other diverse group of animals or plants. The same can be said of sequence data, as a flood of phylogenetic studies is rapidly filling out the avian tree of life. Given that the molecular clock is relatively consistent in birds, biologists can use these sequence data not only to determine the relationships between the branches of the tree but to estimate the timing of evolutionary events, including speciation. By putting these resources together, and applying increasingly powerful computational methods, it is becoming possible to test previously intractable hypotheses about the factors promoting reproductive isolation and shaping patterns of diversity. Genetic data have already taught us mor
