The On Board Call is a bespoke musical interface designed to engage the general public’s interest in wildlife sounds—such as bird, frog or animal calls—through imitation and interaction. The device is a handheld, battery-operated, microprocessorbased machine that synthesizes sounds using frequency modulation synthesis methods. It includes a small amplifier and loudspeaker for playback and employs an accelerometer and force sensor that register gestural motions that control sound parameters in real time. The device is handmade from off-the-shelf components onto a specially designed PCB and laser cut wooden boards. Development versions of the device have been tested in wildlife listening contexts and in location-based ensemble performance. The device is simple to use, compact and inexpensive to facilitate use in community-based active listening workshops intended to enhance user’s appreciation of the eco acoustic richness of natural environments. Unlike most of the previous work in wildlife call imitation, the Call does not simply play back recorded wildlife sounds, it is designed for performative interaction by a user to bring synthesized sounds to life and imbue them with expression.