Birds are feathered, bipedal endothermic vertebrates. Birds are one of the most diverse classes of vertebrates. Bird species have an incredible array of diets and live in many different terrestrial habitats, including the Arctic and the tropics. Birds are believed to have descended from dinosaurs, one of their recent ancestors being the Deinonychus.
Bird: Bipedal, endothermic, tetrapod vertebrate that lays amniotic eggs and has wings and feathers.
Bipedal: Organism that walks or moves on two legs.
Crop: Pocket-like structure that stores food for digestion later.
Gizzard: Food-grinding organ in the digestive systems of birds and some other animals.
Courtship: Behavior that precedes mating and are performed with the intent of attracting a mate.
Cloaca: Body cavity that stores waste/gametes and has an opening that allows them to leave the body.
Incubation: Period of bird reproduction when one or both parents sit on, or brood, the eggs in order to keep them warm until they hatch.
Generalist: An organism that has a varied diet.
Birds are tetrapods (four limbs), but they are bipedal. All have:
A lightweight body is needed for the bird to fly.
Birds have well developed brains, especially in the region that control flight. Birds are indeed very intelligent(not bird-brained at all!).
Diurnal means active during the day, nocturnal means active during the night.