Evolution of growth pattern in birds

Living (neornithine) birds grow up rapidly and without interruption, terminating their growth within one year and, with a few secondary exceptions, starting to fly only after or near the completion of growth. Bone histology has revealed that pre-avian theropods also grew fast for most of the postnatal period, but that this growth was usually intermittent and probably extended for more than one year. We have found surprising evidence for an early...