Eel-bird
The giant eel-bird was a bird-like animal native to the planet Regulus V. The eel-bird must return to the caverns from which they were hatched every eleven years in order to mate.

Like the salmon, Spock referred to the eel-bird while attempting to explain the Vulcan mating ritual pon farr in 2267. ()

de:Aal-Vogel
it:Uccello-anguilla
ja:ウナギ鳥
Avians