PrimariesThe long flight feathers of the outer wing. They grow from the bones of the hand.
SecondariesThe flight feathers of the inner wing. They are anchored to the ulna, a bone of the forearm.
TertialsThe innermost long feathers, next to the body. When the wing is folded they lie over the other flight feathers like a cover.
Greater covertsThe largest row of coverts on the inner wing. They lie over the bases of the secondaries.
Median covertsThe next row of coverts. They overlap the greater coverts the way one row of roof tiles overlaps the row below.
Lesser covertsCover the front of the inner wing, up to the leading edge. Small feathers in several rows.
Primary covertsThe coverts of the outer wing. They lie over the bases of the primaries.
AlulaA few small, stiff feathers on the bird's thumb. They are at the bend of the wing on its front edge.
ScapularsThe shoulder feathers, at the base of the wing. They cover the place where the wing meets the body.
The bones 5
HumerusThe bone of the upper wing, from the shoulder to the elbow.
RadiusThe thinner of the two bones of the forearm. It is on the front side of the wing.
UlnaThe stouter of the two forearm bones. The secondaries are anchored to it.
Hand bone (carpometacarpus)The bones of the wrist and hand fused into one. Primaries are anchored to it.
Finger bonesThe short bones of the three fingers. The outer primaries are anchored to them, and the thumb carries the alula.
How this list was compiled: Every name checked on 2026-09-30 in at least two of these: F. M. Chapman, Handbook of Birds of Eastern North America, 1912, https://archive.org/details/handbookofbi00chap; Cornell Lab of Ornithology, All About Birds, Bird ID Skills: Field Marks, https://www.allaboutbirds.org/news/bird-id-skills-field-marks/; Wikipedia, Flight feather, Covert feather, Alula, Glossary of bird terms and Bird anatomy; O. C. Bradley, The Structure of the Fowl, 1915; J. Jacob, Avian Skeletal System, Poultry Extension (University of Kentucky); Parker and Haswell, A Text-book of Zoology, volume 2, 1910. The sources list says which source gave what. Detail lines are in our own words. Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain geometry; nothing traced. Licence: own work
How it works
These are the parts of a bird wing, on a wing spread out and seen from above. The first drawing names the groups of feathers. The second shows the bones underneath.
Read the full guide
Feathers first, then bones
Numbers 1 to 9 are feather groups: the long primaries and secondaries along the back edge, the tertials next to the body, four kinds of coverts, the alula and the scapulars. Numbers 10 to 14 are the bones of the same wing. Read each name, then press Quiz me.
How the feathers are arranged
The long flight feathers grow from the bones: primaries from the hand, secondaries from the forearm. Coverts are smaller feathers that cover the bases of the feathers below them, row over row like roof tiles, and smooth the air that flows over the wing.
Primaries are on the outer half of the wing, past the bend. Secondaries are on the inner half.
A covert is named for what it covers: primary coverts lie over the primaries.
Questions and answers
What are the feathers on a bird's wing called?
The long flight feathers are the primaries, on the outer wing, and the secondaries, on the inner wing. The tertials are next to the body. Smaller feathers called coverts overlap their bases, and the alula sits at the bend of the wing.
What is the difference between primaries and secondaries?
Where they grow. Primaries are the long feathers of the outer half of the wing, anchored to the bones of the hand. Secondaries are on the inner half, anchored to the ulna, a bone of the forearm.
What is the alula?
A small group of stiff feathers on the front edge of the wing, at the bend. They grow from the bird's first finger, its thumb, which the bird can move on its own.
What bones are in a bird's wing?
The humerus in the upper wing, the radius and the ulna side by side in the forearm, then one fused hand bone, the carpometacarpus, and three short fingers.