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
This bird wing anatomy quiz names a part and you tap it. The wing is a right wing, spread flat and seen from above, with the body at the left and the tip at the right.
Read the full guide
Which row of coverts is which
Three sets lie on the inner wing. The greater coverts are the largest row, resting on the secondaries. The median coverts are the next row forward, and the lesser coverts are the many small feathers that fill the front. The primary coverts are apart from these, on the outer wing, over the bases of the primaries.
Radius or ulna
Both run side by side through the forearm. The radius is the thinner bone, toward the front edge of the wing. The ulna is the stouter one, toward the back edge, where the secondaries are anchored to it. Past the wrist come the hand bone and then the finger bones.
Alula is Latin for winglet.
Questions and answers
What does the alula do?
It helps a bird fly slowly and land. The bird lifts the alula up and forward, which opens a small slot at the front edge of the wing, so the wing can tilt more steeply without stalling.
How many primary feathers does a bird have?
It depends on the bird. Most perching birds have ten and some have nine. Other birds usually have nine to eleven; grebes, storks and flamingos twelve, ostriches sixteen.
What are remiges?
The flight feathers of the wing: the primaries and the secondaries. The flight feathers of the tail are the rectrices. Remiges comes from the Latin for oarsman, rectrices from the Latin for helmsman.
Are tertials flight feathers?
Not strictly. True tertials grow from the upper arm and are not anchored to its bone, so they are not counted with the remiges. They lie over the folded primaries and secondaries as a cover.