Romulan warship of the 2260s whose cloaking device and plasma weapon gave the Federation its first face-to-face encounter with the Romulans.
The Romulan Bird-of-Prey was a compact warship with a broad saucer-shaped hull, twin nacelles and a large bird painted across its underside. It appeared to rely on simple impulse power, but it carried two innovations that alarmed Starfleet: an invisibility screen that let it approach unseen and a plasma weapon powerful enough to destroy shielded outposts.
In Balance of Terror, one of these ships crossed the Neutral Zone in 2266 and destroyed several Federation outposts, breaking a century of silence since the Earth-Romulan War. When the Romulan commander appeared on the Enterprise viewscreen, the crew saw Romulan faces for the first time, and their resemblance to Vulcans stirred suspicion of Spock.
Kirk and the Romulan commander fought a long duel of cat and mouse through a comet's tail and along the edge of the Neutral Zone. Crippled by the Enterprise's phasers, the commander saluted his opponent and destroyed his own ship rather than allow it to be captured.