The Ainu hunted eagles to obtain their tail feathers, which they used in trade with the Japanese.
They also vary the orientation and enlarge the collective surface area of their tail feathers into the shape of a fan.
He noted how remarkably the birds controlled their flight with their tail feathers, which he called the birds' equivalent of ailerons.
The shafts of their tail feathers are stiff and form projections at the end of the tail.
They moult their tail feathers irregularly and the flight feathers of their wings in stages, so that starting at the first moult, they always have some old feathers, some new ones, and some partly grown ones.
The northern gannet has more white in the wings and an all-white tail, the other species having black tips to their tail feathers.
The skin of the head, neck and caruncles (fleshy nodules) becomes bright blue and red, and the snood (an erectile appendage on the forehead) elongates, the birds 'sneeze' at regular intervals, followed by a rapid vibration of their tail feathers.
They display horizontal yellow stripes or bars on the ventral surface of their tail feathers, yellow spots on the ventral surface of the primary flight feathers of their wings, a grey coloured crest and face, and a dull orange patch on each of their cheeks.
Their tail feathers are olive green with a bluish tip.
The first was rampant overhunting to procure huia skins for mounted specimens and their tail feathers for hat decorations.
Next, the male birds move their tail feathers from side to side while quickly vibrating their wings and dragging the tips of them against the ground.
The males display on the lek by stamping their feet rapidly, about 20 times per second, and rattle their tail feathers while turning in circles or dancing forward.