The song of the Chestnut-bellied Flowerpiercer is high pitched, nasal, and has a regular pattern. During the length of the song, it has alternating variety with a semi- metallic sharp inflection (https://www.xeno-canto.org/154850). The song can be described as “ chut-chet-chet-chet-chee-sa’wee, sa-wee-tu-tuu-tslee-chet-tslee, chet, chet chee,chut, sa wee…” (Isler & Isler 1987). The song can last almost 30 seconds and it may give “chet-chet-chee” notes before starting the song again (Isler & Isler 1987). The song can resemble the song of the Glossy Flowerpiercer (Diglossa lafresnayii). The Chestnut-bellied Flowerpiercer’s song is heard more often than its call which its shorter and more subtle. Additional audio recordings of vocalizations of the Chestnut-bellied Flowerpiercer can be heard at Macaulay Library and at xeno-canto.