Sounds and Vocal Behavior

Translated into English, “diablotin” means little devil, presumably as a reference to the bird’s haunting nocturnal calls.

The Black-capped Petrel can be heard overland as a low-octave oooohhhh, oooohhh, ooohhhh-eek . Reynard (recordists notes in ML139296), while collecting sound recordings of the species in Haiti, described the flight calls as “a penetrating resonant growl punctuated by high frequency squeaks.” Simons et al. (5 Simons, T. R., D. S. Lee, and J. C. Haney (2013). Diablotin Pterodroma hasitata: a biography of the endangered Black-capped Petrel. Marine Ornithology 41:S3–S43. Close ) report that the birds fly in pairs or small groups calling back and forth, and it is likely that the primary function of calling behavior is related to pair formation and maintenance. Calling is most often heard in and around the colony locations. Calling of petrels in-flight over land away from colonies is rare and the birds seem to be mostly silent when traveling between the sea and nesting areas, though vocalizations have been heard at dusk on coastlines, presumably when flying to nesting areas (47 Plasencia León, C., Y. Segovia Vega, N. Viña Dávila, and F. Rodríguez Santana (2020). Informe sobre expedición para comprobar la presencia del Pájaro de la Bruja (Pterodroma hasitata) en la localidad de la Bruja, Santiago de Cuba. Unpublished report from Centro Oriental de Ecosistemas y Biodiversidad (BIOECO), Santiago de Cuba, Cuba. Close , 48 Plasencia León, C., N. Viña Dávila, J. Ramón Fuentes, L. Sánchez, F. Álvarez, A. Mustelier, Y. Barrientos, and A. Viña (2022). Informe sobre expedición para comprobar la presencia del Pájaro de la Bruja (Pterodroma hasitata) en la localidad de la Bruja, Santiago de Cuba. Unpublished report from Centro Oriental de Ecosistemas y Biodiversidad (BIOECO), Santiago de Cuba, Cuba. Close ). Occasionally, petrels call from inside their nesting burrows with low grunts or squeaks. The seasonal timing of calls peaks early in the nesting season and steadily declines over the course of the nesting season. At nesting sites, most calling activity is detected during 2–5 hours after local sunset (Fleishman and McKown, personal observation).

At sea, petrels are generally silent. Simons et al. (5 Simons, T. R., D. S. Lee, and J. C. Haney (2013). Diablotin Pterodroma hasitata: a biography of the endangered Black-capped Petrel. Marine Ornithology 41:S3–S43. Close ) summarized the observations of Wingate (21 Wingate, D. B. (1964). Discovery of breeding Black-capped Petrels on Hispaniola. Auk 81(2):147–159. Close ), Imber (35 Imber, M. J. (1985) Origins, phylogeny and taxonomy of the gadfly petrels Pterodroma spp. Ibis 127(2):197–229. Close ), and Lee (personal observation) that individuals at chum slicks occasionally uttered single waaahh or aaa-aw when feeding. On one occasion during December, Lee noted that many petrels he saw at sea were vocal. At sea offshore from Hatteras, North Carolina, petrels have been heard to vocalize when feeding on chum with other petrels but rarely when feeding on chum with mixed flocks (KES, personal observation, 2019–2021).

This species also has a tendency to produce a flute-like sound during nocturnal overflights of the colony, apparently created by wind passing over the birds’ wing (5 Simons, T. R., D. S. Lee, and J. C. Haney (2013). Diablotin Pterodroma hasitata: a biography of the endangered Black-capped Petrel. Marine Ornithology 41:S3–S43. Close ; AB, personal observation).