Family Tree for Birds Reveals Steady Diversification of Avian Species

A team of scientists has compiled what it calls the most comprehensive “family tree” of birds ever assembled, an evolutionary history that reveals that the world’s avian species have become increasingly biologically diverse in recent geological epochs, challenging the conventional wisdom of biodiversity experts. Using fossil evidence, DNA data, and geographical information collected from across the globe, the researchers categorized each of the 9,993 known bird species into a comprehensive lineage, creating a “full global picture of diversification” in space and time. While other types of species have seen declines in biodiversity as available “niches” become filled, the researchers found that the speciation of birds has actually accelerated over the last 50 million years. “Many parts of the globe have seen a variety of species groups diversify rapidly and recently,” said Walter Jetz, a Yale University biologist and lead author of the study, published in the journal Nature. The authors suggest this accelerated rate of diversification may be the result of group-specific adaptations, the opening of new habitats, and the inherent mobility of many bird species that has allowed them migrate to new regions and exploit ecological opportunities.