A bird's primary feathers are the main flight feathers along the outer edge of a bird's wingtip. They often compared to human fingers, though the feathers have no internal joints or muscles and cannot be used for grasping or holding.
(rhymes with "try marry weather" and "buy very heather")
About Primary Feathers
Primary feathers are the "fingertip" feathers, the longest on a bird's wing and the farthest away from the bird's body when the wings are extended. These feathers are attached to the bones of the bird's wing, connected through the skin of the wing. In flight, they are responsible for thrust to propel the bird forward, and each feather can be rotated individually to control flight directions and to adjust lift and air resistance as needed. For example, if the primary feathers are lifted and splayed, the bird's flight will slow and the altitude will drop, a posture many birds use when landing. If the primary feathers are held tightly together in a narrow point, the bird's flight will be faster and more precise, such as a steep hunting dive by birds of prey.
When primary feathers are replaced through regular molting, they are generally shed in pairs, with one feather lost at a time from each wing. The feathers are lost in the same position from each wingtip, which helps the bird stay balanced in flight so no maneuverability is compromised. If multiple primaries are lost through an injury, such as having them torn out by a predator or caught in a wire fence, the flight can be much more difficult and the bird may be much clumsier or unable to turn effectively.
Because primary feathers are essential for flight, these are the wing feathers that are often trimmed on pet birds to minimize their flight capability.
Identifying Birds by Their Primaries
Primary feathers can be used for bird identification in several ways.
- Number: The number of primary feathers a bird has depends on the species and how specialized the feathers are, and most birds have 9-16 primaries. This can be useful for ornithologists or bird banders to properly identify very similar species or subspecies but is less effective for birders in the field since the bird must be held in the hand to accurately count feathers. If a bird stretches well or is sunning, birders may be able to see the primary feathers well enough for counting.
- Color: The color of primaries may contrast with other parts of the wing, creating a bar, patch, or "window" effect on the plumage. This color can be a key field mark for identification, particularly for identifying birds in flight when their primary feathers are easily visible. On some birds, such as many owls, the individual primaries may be striped, spotted, or barred.
- Shape: The overall shape of primary feathers can be useful for identification, especially if the feathers are found after they are shed. The total length measurement can be a clue to the bird species, and whether the tip is rounded, tapered, squared-off, or sharply pointed can also be helpful. These feathers are asymmetrical, and the proportions of the two sides of the feather can also help identify the bird species that shed the feather.
- Flight Position: How the bird holds its primary feathers in relaxed, gliding flight can be a good identification clue. Some birds, such as turkey vultures, have a much wider natural splay to their primaries, while hawks and falcons keep these feathers more closely together.
- Folded Projection: When a bird is perched, the primary feathers will project past other parts of the body, and the length of that projection can help identify bird species. Primaries may be compared to the position of the secondary feathers, tail tip, or other markings on the body for identification purposes.
Primaries in Culture
In cultures where certain birds are honored or otherwise spiritually significant, primary feathers may hold sacred value because of their size and distinction. Many Indigenous cultures use the primary feathers of eagles, hawks, owls, and other raptors for ceremonial dress or adornments. In some African cultures or pagan-like beliefs, primary feathers may be used as part of rituals for potions or spell-casting.
Primary feathers are also known as primary, pennaceous feather, primary remiges (plural), primary quill, primaries (plural).