Question

What period of the Mesozoic era did birds first appear?

Answer 1

The dinosaurs and the mammals appeared during the Triassic period, roughly 225 million years ago. The dinosaurs went extinct 65 million years ago. The Mesozoic Era lasted about 180 million years, and is divided into three periods, the Triassic, the Jurassic, and the Cretaceous.

Answer 2

The earliest known birds appeared during the Jurassic Period of the Mesozoic Era, approximately 150 million years ago.

Thats what google said, sooo you decide what you want to do. :) Good luck!