(noun) Small feathers on a bird's shoulder. In flight, these feathers are at the base of the wing's leading edge.
In some birds, the scapulars stand out as a colorful patch that may also be called an epaulet or epaulet patch. Birds that have this type of prominent scapular feathers include the red-winged blackbird, tricolored blackbird, red-shouldered hawk, white-tailed kite and the blue-winged mountain tanager. Other bird species, including the glossy ibis and bufflehead, may not have a bold color patch on the scapulars but can show distinct iridescence on the shoulder.
Birds with a very well defined scapular patch may use those feathers as part of territorial displays or courtship behavior by flaring their wings and hunching their shoulders to make the color more visible. This can warn off an intruder or advertise fitness to a potential mate.
Scapular feathers can be used for bird identification when they are a distinct color or when the color patch creates a distinct shape on the shoulder. At times, however, the scapulars can be difficult to see because how the feathers lay on the bird's body, any nearby breezes and the bird's posture, all of which can affect how much of the feathers are seen.
Photo – Red-Winged Blackbird © hart_curt
SCAP-you-laar or SCAP-you-lerr
Scapular Feathers, Scapulary Feathers
