Commonly refers to an organisnm capable of flight using appendages called “wings” to generate lift. They act as a glider taking advantage of thermals to increase thier lift and minimise
drag.
They are also usually very light, small and aerodynamic.
Some birds however don’t have the advantage of flight. Some birds, for example the emu, are too big and
heavy to
fly.
Also birds are NOT mammals, they are AVIANS.
My
friend Alex has a pet bird called, “frank”.
The emu won a
war against the australians in, “the great emu
war”.