These two Klingon Birds-of-Prey escorted Duras ship by launching a third attack on Enterprise (NX-01) inside the thermobaric clouds of the Delphic Expanse in 2153. This time, Enterprise managed to evade the attack by entering the Expanse, something which Duras was willing to risk, but the other ship captains were not. The two Klingon Birds-of-Prey reluctantly withdraw while Duras continued his attack on Enterprise. (ENTepisode: "The Expanse")
This Bird-of-Prey was seen in the "mirror" title sequence for the two part "In a Mirror, Darkly". Footage of Enterprise attacking Duras's bird-of-prey in ENTepisode: "The Expanse" was used to depict this attack.