They have claws and scales on their feet, and also have an amniotic egg, with a brittle shell, that is incubated in a nest. They have modified scales on the rest of their body called feathers, which are lightweight and provide insulation and flight. They have modified front appendages called wings, which also helps them fly, with help from strong muscles attached to a large sternum. They have a four chambered heart, and are endothermic, or warm-blooded. They have one-way lungs to get more oxygen.
Birds have good vision, sense of smell and have a magnetic field detection.
Lastly, class mammalia is what humans belong to. They have a four chambered heart, two way lungs, hair made of keratin, mammary glands, a diaphragm, teeth, endocrine system and are endothermic. Placental mammals give birth to live young, and house the embryo until it is complete. They have a placenta as a way of exchanging nutrients during development. This group includes most mammals, including humans.