Curiously, Star Trek‘s Klingons and Romulans both have Bird-of-Prey starships. First seen in Star Trek: The Original Series season 1, episode 8, “Balance of Terror”, the T’Liss-class Romulan Bird-of-Prey is so-called because of the predatory bird painted on its hull. Later, in Star Trek: The Original Series season 3, episode 2, “The Enterprise Incident”, a Romulan ship looks just like the D7-class Klingon battle cruiser in TOS season 3, episode 13, “Elaan of Troyius”. Instead of being a Romulan ship, the iconic D7 would go on to become the basis for almost all Klingon ships in Star Trek shows.

https://screenrant.com/star-trek-klingons-romulans-bird-of-prey-explainer/