Bird feathers
Primary feathers are located at the wing tip and provide thrust; secondary feathers are located close to the body and provide lift.
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"OpenStax College, Birds. October 17, 2013."
http://cnx.org/content/m44694/latest/Figure_29_05_01.jpg
OpenStax CNX
CC BY 3.0.
