The Finger Tips of Bird's Wings - Primary feathers

Primary feathers are the "fingertip" feathers, the longest on a bird's wing and the farthest away from the bird's body when the wings are extended.

These feathers are attached to the bones of the bird's wing.

  The skin and muscle is strong to provide support for the feather. 

In flight, they are responsible for thrust.

  This helps to propel the bird forward

Each feather can be rotated individually to control flight directions 

They can be adjusted for lift and air resistance.

if the primary feathers are lifted and splayed, the bird's flight will slow and the altitude will drop.