"Bird wings" refers to the specialized body parts found on birds that help them fly. These wings are shaped to create lift and adjust the bird's flight direction. Full definition
On about the fourth attempt to move in close, I crossed a small clearing and was about to swing around a bush when over it I saw a number of birds wing into the air with loud chirping. (si.com)
Fox swears she's no angel, just a girl born with bird wings, and people let this be a conversation ender. (rottentomatoes.com)
A «travel cage» is acceptable if it is large enough for the bird to stretch his or her wings and has an appropriate perch for your bird (svg-vets.com)