All birds have feathers, although not all birds can fly. We associate feathers with flying, but some, like down, are also for insulation. Other feathers are just for decoration, such as crests and plumes.
Birds have backbones, however, birds have lighter sometimes hollow bones with gaps and air sacs to keep them lightweight making flight easier.
All birds have a beak, which is a keratin-covered horny projecting jaw. These beaks help with specific food that birds eat, and are also sometimes used as tools for drumming, preening, carrying, and even drilling. Their beaks can also be a powerful weapon, and they also help regulate their body temperature. Bird communication is a highly developed skill, and many bird species communicate vocally through elaborate songs and calls. They also make nonverbal noises that are part of their communication abilities. They use these abilities for parent-chick recognition, community cooperation, and territorial defense.
Birds are warm blooded, and they have a very high metabolism. They eat their weight daily and their food turns into usable energy quickly. They have high body temperatures.
Every bird has a wishbone that protects the chest cavity during wing beats. It protects their four-chambered heart, and other organs.
Birds lay eggs as part of their reproductive cycle. Eggs size, shape and markings as well as the number of eggs laid varies for each bird species.
All birds have wings, even those who don’t fly, have adapted wings that they use for swimming, protecting their territory, and courtship dances. Wings vary on whether the bird flies and how they fly. Migratory and non-migratory birds have great navigational skills. Some birds migrate thousands of miles to the same places each year. Birds that don’t migrate use their skills to visit the same food and nesting sites each year.
All birds have two legs, these legs have evolved to different shapes and lengths to suit their needs.
These are some of the ways that all birds are the same. With around 10,000 birds species we shall never tire of discovering the differences.