Beaks. Birds have beaks, which are made of keratin and bone. Beaks come in a variety of shapes and sizes, and they are used for a variety of purposes, such as eating, drinking, and preening.
Wings. All birds have wings, which are used for flying. Wings are made up of a long bone, called the humerus, which is connected to the shoulder joint. The humerus is followed by two shorter bones, called the radius and ulna, which are connected to the wrist joint. The wrist joint is then connected to the hand, which is made up of five digits, called the fingers. The fingers are covered in feathers, which help to create lift and drag.
Laying eggs. All birds lay eggs. Eggs are made up of a hard shell, a white yolk, and a yellow vitelline membrane. The yolk contains the nutrients that the embryo needs to grow and develop. The vitelline membrane protects the yolk and keeps it from drying out.
Endothermic metabolism. Birds are endothermic, which means that they are able to generate their own heat. This allows them to maintain a constant body temperature, even in cold climates.
High metabolic rate. Birds have a high metabolic rate, which means that they need to eat a lot of food in order to stay energized.
Keen eyesight. Birds have keen eyesight, which helps them to find food and avoid predators.
Strong sense of smell. Birds have a strong sense of smell, which helps them to find food and avoid danger.
Good hearing. Birds have good hearing, which helps them to communicate with each other and avoid predators.
Migration. Many species of birds migrate long distances in order to find food and a suitable climate.
Social behavior. Many species of birds live in flocks or colonies. This helps them to defend themselves against predators and find food.
Intelligence. Birds are intelligent creatures, and some species are even able to learn how to speak and use tools.