How are birds different from reptiles?

Differences between birds and reptiles:
– For birds, flight is the main mode of movement;
– High and constant body temperature;
– Four-chambered heart, in which there is a complete separation of arterial and venous blood;
– Fusion of many bones;
– The presence of spongy lungs and air sacs;
– The central nervous system is more developed;
– Building nests by birds, hatching and caring for chicks