Following are the difference between aves and mammals:
(a) Aves also known as birds are group of vertebrates that can fly. While mammals are group of vertebrates that have mammary glands.
(b) Aves lay eggs while mammals give birth to babies.
(c) Aves have wings whereas mammals have hands, hooves, and paws.
(d) Aves have feathers while mammals have fur or hair.
(e) Aves have dual respiratory cycles whereas mammals have single respiratory cycle.