Crebain

"Its moving fast...against the wind" —Boromir Crebain (singular: craban) were a species of large Crow-like black birds in Middle-earth.

Overview
The Crebain were large, black crows who were native to Dunland and the Fangorn forest and made harsh croaking noises. Like crows and ravens, the birds seemed to possess at least some level of intelligence. They were often used as servants and spies by various evil powers. During the War of the Ring, a flock of crebain were used by Saruman as spies to get information on the Ring-bearer and search for him.

Etymology
Crebain "crows" would be the regular form of Sindarin *craban "crow," a word which (while unattested) seems to have been adopted by Tolkein from Indo-European languages, particularly a pre-Germanic form *krabn-, whence the proto-Germanic *hrabnaz, from which descended both Old High German hraban and English raven.