92. Notes on the vocalizations of Pearled Treerunner (Margarornis squamiger)

Pearled Treerunner has a variety of high-pitched vocalizations, varying from short single notes (also doubled and tripled) to longer rattles, either at a constant pitch or slightly going up and down, and with variable pace. It is unclear which of these could be named 'territorial loudsong'. In literature there is also little clarity. The fast high-pitched trill going up and down in pitch seems a good candidate to be named 'song', although it is heard much less than the stuttering rattles of high-pitched notes. The latter are however typically given in mixed-species flocks, when few birds really sing a territorial song. The trill is often preceded by a variable number of higher-pitched notes or a stuttering rattle (Fig. 1).