Here are some interesting facts about birds:

Size

The ostrich is the largest bird in the world, while the bee hummingbird is the smallest. 

Eyes

A bird's eye takes up about half of its head. 

Flight

Birds have hollow bones, which makes it easier for them to fly. A bird's heart can beat up to 1,000 times per minute while flying. 

Communication

Birds use their bodies, calls, songs, and dances to communicate. Some birds, like parrots, can mimic what people say. 

Migration

Many birds migrate, meaning they fly to different locations. The Arctic tern has the longest migration, traveling a round trip of 22,000 miles. 

Hollow bones

Birds have hollow bones, which makes it easier for them to fly. 

Sleep

Some scientists believe that albatrosses have sleep patterns that allow them to visually navigate while in flight. 

Swimming

Penguins are the only birds that can swim, but not fly. They use their flippers to propel themselves through the water. 

Brain size

Crows have the largest brain in relation to their body of any avian family. 

Poisonous bird

The Pitohui of Papua is the world's only poisonous bird. The poison is found on its skin and feathers.