Often the bird announces its presence by the high-pitched but noticeable sound of the wings beating rapidly (50 -100 times a second) as it hovers, hence the common name in English.
I have a lot of flowers they love, like red bee balm and columbines, and I usually hear them before I see them. If I were just using my eyes, I might miss some of the show. The odd noise alerts me to pay attention and look around more closely.
@ragingloli‘s comment piqued my curiosity and so I just discovered that in French, Italian, Portuguese and Spanish it is also le (il, o, el) colibri. and in Dutch, de kolibrie.
Plus, apparently the genus is colibri or colubris.