User blog comment:Monkey D. Luffy;Gomu Gomu No Mi/Friendly Hacker/@comment-26947480-20150911112011/@comment-24808864-20150913015407

"The scientific consensus is that  birds are a group of theropod  dinosaurs that evolved during the Mesozoic Era. A close relationship between  birds and  dinosaurs was first proposed in the nineteenth century after the discovery of the primitive  bird Archaeopteryx in Germany."

Search wikipedia 'Origin of birds.'