The USS Kestral (NCC-1766) was a Constitution-class Federation heavy cruiser starship of the Achernar-subclass, ordered for construction in the 23rd century, named for the star Kestral.
Construction of Kestral was authorized by the Starfleet appropriation of stardate 5930. (TOS reference: Star Fleet Technical Manual)
In 2290, the Kestral was being used in a bridge crew training simulation in the Klingon Command Academy. In one simulated mission, the Kestral was encountered by the simulator vessel in the Cain system, along with the USS Eagle.
In this simulated mission, both the Kestral and Eagle were older-style starships which had been brought out of mothballs to be refitted to modern specifications, in order to replace "losses" suffered against the Klingons. (TOS video game: Klingon Academy)
- The stardate given would seem to suggest this ship was ordered during the TAS era. It is not positively known if this vessel was built, only that it was authorized and depicted in simulations.