There are more than 10,000 species of bird around the world, they all evolved from the theropod dinosaurs of which Tyrannosaurus rex was one. They are a seemingly diverse bunch of animals from the tiny Firecrest and the Hummingbirds to the Emu and Ostrich by way of the Vultures and the Cockatoo.
There are 137 families of perching birds, the so-called passerine birds, which have three toes pointing forward and one pointing back. The Passeriformes account for almost two-thirds of all bird species and are found across the globe. The term passerine comes from the Latin word for that archetypal perching bird, the House Sparrow (Passer domesticus). Passero or passera is Italian for Sparrow.
Anyway, a new DNA analysis reveals that all of those thousands of species of Passeriformes have a common ancestor that lived 47 million years ago in Australia. Discussed in more detail by Eleanor Imster in EarthSky.
Meanwhile, a genetic analysis in Science this week, explains why that Australian resident, the Emu, and indeed Ostriches and other ratite birds cannot fly.