Scientists have puzzled for centuries over how different groups of birds are related. Did birds that look physically alike, such as falcons and hawks, arise from a common ancestor, or did they reach those similarities independently? This line of inquiry was given an immense boost in recent years when an international research team unraveled the genetic codes of 48 species of birds. The results are emerging, including a revised evolutionary tree for birds that places falcons such as this American Kestrel (right) - and parrots such as this Rainbow Lorikeet (left) - on adjoining branches.
