alula

Also, in all of these photos, you cannot see "hanging" alula or primary coverts often shown by Rook.

同时，所有的照片都看不到『悬挂起来』的小翼羽或大覆羽，通常秃鼻会有这个特徵。

The team also noted a hinged flap near the base of the wing, called an Alula, which is deployed at right angles to the wing, which may be being used as a air flow-control device.

这个小组还注意到，翼根附近铰接的副翼，被称为小翼的，对翼成直角配置，它可能被用来作为空气流量置。