SPECIES

Black Falcon Falco subniger Scientific name definitions

Stephen Debus
Version: 2.0 — Published March 17, 2023

Sounds and Vocal Behavior

Introduction

Black Falcon is mostly silent away from the nest. Around the nest through the breeding cycle, it gives various cackling, creaking, and whining calls typical of large Falco. Some early accounts of calls may include confusion with the calls of the Brown Falcon (Falco berigora). Reliable anecdotal descriptions were summarized by Marchant and Higgins (1). The calls described and shown (with spectrograms) by Jurisevic (101) were from restrained or distressed captive birds. Studies of the calls of breeding falcons in the field (95, 7, 38, 18, 8, 9, 10) were interpreted and supplemented by new data, with spectrograms, by Debus et al. (102) and summarized by Debus (3). Because transliteration of bird sounds into words is subjective, universally onomatopoetic terms are generally used here (e.g., cackle, chitter, whine).

Vocalizations

Vocal Development

Young nestlings beg using plaintive, insistent peeping notes, which change into the typical Falco juvenile begging whine during the last three weeks in the nest, with the whine persisting throughout the post-fledging dependence period. Advanced nestlings also give an adult-like cackle, or hiss, when threatened; the whine can be deep and resonant or the cackle high-pitched with a screaming quality, when a nestling or fledgling is handled (1, 7, 102).

Vocal Array

Black Falcon has several main vocalizations, as described by Debus et al. (102), who also reinterpreted previous descriptions by Marchant and Higgins (1), Debus and Olsen (5), and Charley et al. (9).

A guttural, hoarse, clipped cackle of 2–3 notes/s , which is slower and less excited or strident than the equivalent cackle of the Peregrine Falcon (Falco peregrinus), and slightly deeper in pitch, though the cackle notes can rise to a churring or shrieking quality when defending the nest (9, 11), or a screaming quality when a fledgling falcon is restrained by a perceived enemy. The Black Falcon's slow cackle, typically rendered as kak-kak-kak..., gak-gak-gak... or chuck-chuck-chuck..., is essentially identical to the slow cackle of the Laggar Falcon (Falco jugger). Single sharp cackle notes may be given if the falcon is surprised, startled, or mobbed (1, 7).

An abrupt creaking call , which is sometimes disyllabic ("double cluck") when uttered as a single phrase (rendered as chip, chik, chip-chip or chick-chick), can become a falsetto (squeaky eep or scratchy eeik) during aerial display. This call becomes a long rattle or "chuckling" (kik-kik-kik...) when uttered continuously, in triplets with a brief pause in between, and is very similar to the long rattling call of the Saker Falcon (Falco cherrug). A soft version of the creaking call or rattling extension is "ticking" or "chittering," or a more musical trill (9, 10). A "soft whistle" (1) is apparently the trill or a "chirruping" version of it.

A whining call (sometimes rather inaptly termed a wail) , being a long (0.5–1 s), plaintive and rising note, rendered as waik, repeated in series (1–2 notes/s), is very similar to the whining call of the Saker Falcon. A single low, deep moan is occasionally uttered by an adult Black Falcon when approaching the nest tree or a roost tree (8, 102), and a deep, resonant whining series can be given by a handled nestling (7). A deep, drawn-out moaning call can also be given when a falcon is surprised or annoyed (1). The whine can take on a squealing quality when a falcon is under attack by a conspecific (19).

A maternal deep croaking note is given at the nest, typically when feeding chicks (1).

Geographical Variation

None known or suspected.

Phenology

Black Falcon calls mainly during the breeding season (late autumn to late spring), frequently and daily at all stages of the breeding cycle, with juveniles continuing to utter food-begging calls until late spring or early summer (7, 38, 9, 102; SJSD). Dependent juveniles also cackle at one another when interacting in the air (18).

Daily Pattern of Vocalizations

During the nesting season, Black Falcon calls at any time of the day, from up to an hour before sunrise, and sometimes when going to roost at dusk, though most frequently (juveniles and female parents) when food-begging to a parent or to the male, and (adults) when defending nestlings against the intrusion of large eagles (95, 7, 38, 9, 19, 102).

Places of Vocalizing

Nestlings call from the nest; fledglings also call from the nest, as well as from nearby perches in trees, and in the air. Adults call from perches, the nest, and in the air. Fledglings may call on the ground when mantling a prey item against siblings (SJSD).

Sex Differences

Calls of the female are somewhat deeper or more guttural than those of the male, whose cackle can be more Peregrine Falcon-like. The female's disyllabic creaking call can be rendered as kuk-chip or cluck-cluck (1, 38, 8, 9, 102). During the breeding cycle, the female is much more vocal than the male, more frequently giving the three main call types (cackle, creaking, and whining) through the cycle, except that mainly the male uses the mono- or disyllabic creaking call during the nestling period, whereas the female more frequently prolongs the creaking call into a rattling or chittering series in the earlier stages of the cycle (102).

Social Context and Presumed Function of Vocalizations

Information is taken mainly from studies by Debus and colleagues (7, 38, 8, 9, 10, 19, 102, 11), which clarify the somewhat confused earlier literature on call descriptions.

The cackle is typically given when the adults are defending the nest or young against the intrusion of other predatory birds, mostly large eagles, into the falcons' territorial airspace, but also sometimes by females when defending nestlings or fledglings against a human on the ground below the nest (9, 10, 19, 102, 11). It is also given by females when performing a high "winnowing" display flight (see Behavior: Locomotion: Flight) against, or in pursuit of, intruding conspecifics or other raptors, or by either sex when under attack or mobbing by other birds, and sometimes by the nesting female in the male's presence (7, 8, 9, 19). The cackle appears to be a defensive, challenging, or assertive call, sometimes also given by the female apparently to induce the male to hunt or transfer prey (9).

The creaking call and its variants are given around the nest during the breeding cycle. The female's disyllabic version is given when inspecting, testing, and occupying a nest or potential nest, and at other times through the cycle, e.g., between mates at the nest or when the female is "mobbed" by hungry young, or between cackle calls when about to defend the nest (95, 38, 9). The male's mono- or disyllabic version is given when showing or enticing the female to a potential nest, and as a food-call when bringing prey to the nest during the breeding cycle (19, 102). The falsetto version is given during aerial advertising display flights (45, 103), apparently mostly by the male, and reportedly by both sexes in courtship flight and at the nest in the pre-laying phase (45, 95). Softer mutual "ticking" or chittering versions are given by either sex when together at the nest in the pre-laying phase, and become the louder rattling or chuckling series in the copulation phase and thereafter (10, 19). Females give the rattling series when joining the male at the nest, or before and after copulation, and by either sex preceding, during, or following intraspecific conflicts with intruders (19). The soft trill is given by the male when joining the perched female near the nest (9), apparently as a greeting or appeasement call. "Parrot-like" calls by a courting pair in autumn (74) were apparently the musical trilling or chirruping version of the extended chittering-type creaking call and not, as suggested (21), a misidentification of the falcon species. The creaking calls and their variants appear to be contact and intention-signaling calls between mates, and the louder rattling version appears to have an assertive component.

The whine is primarily a food-begging call, given by the female through the breeding cycle and by advanced nestlings and dependent juveniles (1, 7, 9, 19). It is also sometimes given by either sex when approaching the nest in the pre-laying phase, e.g., the male with food for the female and apparently by the male during copulation while the female utters the long rattling call, although it is mostly the female that gives the whine call during copulation (95, 38, 10, 19). An intruding Black Falcon under attack by the territory owner may also whine, though with a squealing quality (19). The whine appears to have a soliciting function.

Nonvocal Sounds

Breeding adults, when stooping at intruders at the nest, produce a whistling rush of air through feathers (104, 11; SJSD). Falcons stooping at prey or other raptors also produce an audible whoosh at close range (45, 22, 51, 91, 105, 106, 89). This whooshing sound may just be the wind rushing over feathers, rather than having a function; it feels intimidating to a human climbing to the nest, but whether deliberately so is unknown.

Recommended Citation

Debus, S. (2023). Black Falcon (Falco subniger), version 2.0. In Birds of the World (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.blafal1.02