11 Lesser coverts These shape the part of the wing that meets the oncoming air. Main coverts Covert feathers protect the flight feathers below. First fingerWrist bones Second finger Wing bones The wing bones form a system of lightweight levers for the wing muscles to act on. Thumb Forearm bones Part of the upper arm bone Wings and arms Bird wings and human arms have evolved from the same type of limb. Bones of the bird’s wing Bones of the human arm Secondary flight feathers The “secondaries” add to the curve that provides lift. Tertiary flight feathers These innermost flight feathers shape the wing into the body to prevent turbulence during flight.