The Bird of Prey achieves warp flight using a different system of energized alloys from other ships in the IKDF fleet. Most civilizations that are capable of faster than light travel use circular or oval rings of space-bending metals and composites. The familiar 'warp coils' - housed in stand off nacelles or incorporated within a starship hull - warp space and provide propulsion when they are exposed to high energy plasma.
Early Klingon, Vulcan, and Romulan vessels used this system to make their way through interstellar space, employing a variety of cryogenic fuels and antimatter to achieve greater and greater speeds and distances. While plasma reactions had originally been triggered directly within the nacelles, advances in pumping super hot plasma from remote - and protected - engines allowed for larger, more powerful systems. Magnetically line conduits could be routed through different structures. Crystalline materials such as ikemenite, faslonite, and dilithium became standards for regulating the furious energies and smoothing out the plasma frequencies within the core.
Design engineers within the Imperial Klingon Defense Forces, with ship commanders taking an active role in deciding what systems were to be installed in their ships, experimented early in the 22nd century with reshaping the usual nacelle configuration for new classes of fast, stealthy attack vessels.
It was determined that the sequential energizing of warp alloys did not necessarily require the 'coils' to be coils at all, but the alloys could be compacted into flat sheets. Beginning with Klingon vessels of the late 2120s, the energized warp wing was born, leading to the development of the B'rel-class Bird of Prey with its imposing bird shape.
In the B'rel class, plasma produced in the twin warp cores is allowed to fill and pressurize the central horizontal conduits that lead to the wings, through penetrations in the engineering hull on Deck 5. Each central conduit has a variable aperture duct, which works in concert with the wings to provide different amounts and pressures of plasma to the warp system depending on the flight mode - liftoff/landing, cruise, and attack.