You obviously don't know what floating cause you cant float in the air the Mobs flap their wings. they used the same birds from xi those didn't float either they just hover in place which is still flying in a sense. because helicopters can hover and still maintain flight.

So i will ask you one more time what do you want the birds to do. Resting on the ground then fly again after a while? Or do you just want them flying really high in the sky and flying everywhere?