Early Klingon Bird-of-Prey of the 2150s, flown by Duras in his last pursuit of Enterprise toward the Delphic Expanse.
In the 2150s the Klingon Empire fielded an earlier Bird-of-Prey design, with an angular forward section on a neck, two warp nacelles above the impulse engine and downswept wings mounting heavy disruptors. It served as a patrol ship and escort, often alongside the larger D5-class battle cruisers.
In The Expanse, the disgraced Klingon officer Duras pursued Enterprise in a Bird-of-Prey as Archer set out for the Delphic Expanse, and his ship was destroyed in the attempt. In Borderland, the renegade Augments attacked and boarded a Klingon Bird-of-Prey and killed its crew.