Are you one of the many cat owners who has a “chitterer”? My current cat just gazes in helpless abandon at birds outside, but most of the cats I’ve had made a clicking chittering call. There’s disagreement about what this means, from the side effect of an anticipatory jaw movement to a deliberate “bird call” to sheer frustration.
In margays, though, it’s an explicit imitation of prey. It probably helps that tamarins have some calls that overlap with cat sounds. As Laelaps explains, because vocalizations can be used to mark territory, “a monkey or other prey animal that thinks it is coming over to tell a competitor to buzz off may instead come face-to-face with a margay.”