A humming bird (Thaumastura cora) having two of the tail feathers next to the middle ones very long in the male; -- called also cora humming bird.

the hollow shaft of a feather

The solid part in the center of a feather, in the part nearest to the tip. The quills are attached to this part.

the hard center "tube" of a feather The shaft of a feather pen holds the ink.

The stem or base of the feather.

The central hollow strut of a feather, giving it support.

The solid, or mostly solid, center spine of the feather. Also called the "rachis." Strengthening struts run across the shaft's core like steps on a ladder. See image above. When choosing primary feathers for making quill pens, keep in mind that the shaft curves to the right on the bird's left wing, and vice versa. Right-handed writers should choose left wing-feathers.