mega-birdos
Pterosaurs weren't birds; they weren't even dinosaurs.
I reckon if you gave me a bit of armor of some sort, a good knife and a baseball bat, I could take one on.
Yeah, try that with a cassowary. Or even an ostrich or an emu. Australia lost two wars to emus. (Again, pterosaurs weren't birds, but since you're using birds as a comparison...)