remiges

Remiges are the flight feathers of a bird’s wing. In most birds the remiges are divided into primary remiges, the long outer feathers at the wing tip attached to the manus, and secondary remiges, attached to the ulna. The term can also be used to refer to the entire set of wing flight feathers, excluding covert feathers.

Anatomy and structure: Remiges are pennaceous feathers with a central rachis and two vanes formed by interlocking barbules. They are derived from keratin and grow from follicles that are supplied with blood during growth and then keratinize. The outer primaries typically extend beyond the wing tip, while secondaries are shorter and fill the inner wing. The leading edges of flight feathers are often tapered and asymmetrical, which helps control air flow and lift.

Function: Primary remiges generate thrust during the wing’s forward stroke and contribute to speed and maneuverability, particularly in fast or agile flight. Secondary remiges provide lift and improve wing-beat efficiency and stability. The arrangement and condition of remiges allow birds to adapt wing shape for various flight modes, including rapid flapping, gliding, and precise steering.

Moults and variation: Birds replace remiges through regular moults, usually in a way that preserves some flight capability, often one wing at a time. The exact number of primaries and secondaries varies among species, typically around nine to eleven primaries per wing and a similar number of secondaries, with species-specific patterns used in identification and taxonomy.

Significance: Remiges are central to avian locomotion and are a focal point in studies of flight mechanics, ecology, and evolutionary biology.