Original Description:
Avian enthusiasts: Grab your binoculars, because it's time to learn about birds! There are 10,000 unique species of birds, but they all share some characteristics. Birds are warm-blooded vertebrates with feathers, wings, and a beak or bill. The bones of most birds are hollow, and are fused together for strength to help them fly. Some birds fly tens of thousands of miles in a lifetime, due to their seasonal migration patterns. A bird's super-efficient respiratory system supplies its strong flight muscles with plenty of oxygen—and, of course, helps it sing! But birds don't just sing to show off: Their songs deliver messages and can help attract mates. The evolution of some of these traits can be traced back to birds' ancestors: the dinosaurs! Don't believe us? Check out this BrainPOP movie—it's for early birds, night owls, and everyone in between!