What are quill feathers and what is their function in birds?

A) Quill

Quill feathers, also known as flight feathers, are the primary type of feathers used for flight in birds. These include the large, strong feathers on the wings (remiges) and tail (rectrices). They are essential for generating lift and thrust, allowing birds to fly.

Other feather types like filoplumes have sensory functions, coverts help smooth airflow, and down feathers provide insulation, but they do not directly contribute to the mechanics of flight.