Birds as Dinosaurs It is currently, widely agreed that birds are the descendants of dinosaurs. This is due to the close similarity of advanced theropod (gl) dinosaurs and birds.
Birds are warm-blooded and the crucial question is:
When did their warm-bloodedness develop?
Some people claim that warm-bloodedness would have had to evolve before flight (to provide the large amounts of energy needed). However, as it is not possible to pinpoint the moment that warm-bloodedness began in the lineage, birds are almost irrelevant when considering dinosaur temperature control.