While a relatively enlarged brain with the capacity required for flight was present in one of the earliest known birds, Archaeopteryx, the researchers said a few earlier non-avian dinosaurs had brains as large as or larger than that of Archaeopteryx.
That suggests some dinosaurs suspected of possessing flight capability also would have had the neurological hardwiring necessary for this behavior, they said.
"Archaeopteryx has always been set up as a uniquely transitional species between feathered dinosaurs and modern birds, a halfway point," study lead author Amy Balanoff, a research associate at the American Museum of Natural History said. "But by studying the cranial volume of closely related dinosaurs, we learned that Archaeopteryx might not have been so special."
Birds can be distinguished from other living reptiles by their brains, which are enlarged compared to body size, a so-called "hyperinflation" considered important for providing the superior vision and coordination required to fly.
The new study suggests a hyperinflated brain first appeared in non-avian dinosaurs, the researchers said.