(syn. Chaetura Ϯ Lesser Antillean Swift C. martinica) Gr. ακανθα akantha thorn, spine < ακη akē point; ουρα oura tail; "Mr Stephens, in the family of Hirundinidæ, described in his supplement to the continuation of Shaw's Zoology, has separated under the generic title of Chætura, a group of birds which I had named Acanthura in my cabinet. ... H. acuta of Stephens may stand as the type ... The strong tail-feathers with their spurious naked terminations may probably be useful in supporting the animal in the attitude of Woodpeckers, while building in the cavities of rocks" (Guilding 1828).