Nombre en español: Halcón Murcielaguero

Nombre en inglés: Bat Falcon

Nombre científico: Falco rufigularis

Familia: Falconidae

El halcón murcielaguero​ (Falco rufigularis), también conocido como halcón plomizo menor, halcón golondrina y halcón negro chico es una especie de ave falconiforme de la familia Falconidae propia de América, desde México hasta Argentina.

Es un ave crepuscular y nocturna que aunque su nombre lo indica no se alimenta únicamente de murciélagos. Su nombre Falco proviene del latín tardío y significa Halcón. El epíteto rufigularis proviene del latín rufus = rojo y del latín moderno gularis = garganta.

Características

Tamaño y Forma

Mide de 24 a 29 cm, el macho pesa de 108 a 148 g y presenta una envergadura de 56 a 58 cm. La hembra pesa de 177 a 242 g y presenta una envergadura de 65 a 67 cm. Presenta iris café oscuro, pico negro con base gris, cera y patas amarillas. El adulto presenta cabeza y partes superiores negras con las plumas de la alta espalda hasta las cobertoras caudales con márgenes grisáceos. Presenta garganta, lados del cuello blancos y una pequeña banda en el alto pecho naranja; bajo pecho y la superficie interna del ala de color negro finamente barradas de blanco; vientre, muslos y cobertoras infracaudales de color rufo castaño. Su cola es bastante larga y de color negruzca con varias barras finas blancas o grisáceas y punta blanca o ante. La hembra es más grande que el macho y el individuo inmaduro es enteramente negro por encima con garganta más coloreada de ante y tinte leonado en el pecho.

Distribución y Habitat

Se distribuye desde el norte de México hacia el sur por Centroamérica hasta Panamá. También en Suramérica por Colombia, Ecuador, este de Perú, Venezuela, Guayanas, Trinidad, norte y este de Bolivia, Paraguay, norte y noreste de Argentina y Brasil. En Colombia se encuentra por debajo de 1600 m de altura sobre el nivel del mar en todo el país excepto en el nudo de los Pastos.

Habitan en bosques de tierras bajas hasta bosques montanos. Utiliza bosques de bosque, pasos de carreteras, riberas de ríos y áreas agrícolas con árboles dispersos. Comúnmente caza por encima del dosel y al parecer muestra cierta preferencia por bosques no perturbados.

Especies Similares

Muy similar al Halcón Colorado (Falco deiroleucus) el cual es de mayor tamaño, con banda pectoral negra menos amplia, barrado del bajo pecho más ancho y naranja del alto pecho más reducido.  

Diferencias Regionales

Se reconocen tres subespecies: F. r. petoensis, F. r. rufigularis y F. r. ophryophanes de las cuales las dos primeras se encuentran en Colombia. La raza petoensis se encuentra al oeste de los Andes y la raza rufigularis al este de los Andes.

Alimentación

Se alimenta principalmente de murciélagos, aves e insectos grandes que atrapa en el aire. Entre sus presas han sido registradas golondrinas, vencejos, colibríes, libélulas, polillas, grillos y cigarras. Sin embargo, en ocasiones también captura presas en el suelo en donde encuentra pequeños lagartos y ratas. 

Reproducción

En Colombia se han registrado individuos en condición reproductiva desde febrero a marzo en el golfo de Urabá. También se han registrado un nido en febrero en Trinidad, huevos en marzo en Venezuela y en abril en Guyana. Anida en cavidades de árboles, agujero cavados por loros, nidos de trogones abandonados, termiteros y edificaciones abandonadas. Pone de dos a cuatro huevos y las crías empluman totalmente del día 35 al 40 después de la eclosión. El macho alimenta a la hembra antes de la cópula, al parecer como parte del cortejo y durante el periodo anidación. 

Comportamiento

Permanece solo o en parejas. Es un ave principalmente crepuscular y nocturna que caza desde perchas altas y expuestas desde las cuales captura presas que se mueven por encima del dosel o en zonas abiertas. Algunas veces vuela baja muy a ras del dosel tratando de hacer levantar presas para capturarlas. En una ocasión se observó un individuo volando al dosel de un árbol y aferrarse a una rama mientras aleteaba por algunos segundos, para luego volar en busca de los insectos espantados mediante esta técnica. 

Taxonomía

Anteriormente llamada Falco albigularis. Probablemente pertenece al complejo F. subbuteo. Su similitud con F. deiroleucus ha sido considerada como reflejo de que hubo un ancestro común reciente, más que como evidencia de convergencia evolutiva. La validez de las razas petoensis y ophryophanes en ocasiones ha sido cuestionada bajo el argumento de que representan variación clinal. Las poblaciones del norte de su distribución han sido consideradas como una raza distinta (petrophilus) actualmente incluida dentro de petoensis.

Historia natural

Se encuentra en bosques, selvas y vegetación cercana al agua. No es gregario, por lo cual siempre se le observa solo o con su pareja. Se alimenta de otras aves, mamíferos, insectos y reptiles pequeños.

Suelen anidar en los huecos de los árboles, en arbustos, edificaciones abandonadas entre otros. Ponen 2 o 3 huevos de un color café.

Subespecies

Se conocen tres subespecies de Falco rufigularis:

• Falco rufigularis petoensis – tierras bajas y húmedas desde el norte de México al sur de Ecuador (al oeste de los Andes).
• Falco rufigularis rufigularis – tierras bajas del norte de Sudamérica hasta el sur de Brasil y norte de Argentina; Trinidad.
• Falco rufigularis ophryophanes – meseta de Brasil y zonas adyacentes de Bolivia, Paraguay y Argentina.

Bat falcon

The bat falcon (Falco rufigularis) is a falcon that is a resident breeder in tropical Mexico, Central and South America, and Trinidad. It was long known as Falco albigularis; the names Falco fusco-coerulescens or Falco fuscocaerulescens, long used for the aplomado falcon, are now believed to refer to the present species.

The female bat falcon, at 30.5 cm length, is much larger than the 23-cm-long male. Adults have a black back, head, and tail. The throat, upper breast, and neck sides are creamy white, the lower breast and belly are black, finely barred white, and the thighs and lower belly are orange. Young birds are similar, but with a buffy throat. The call of this species is a high pitched ke-ke-ke like the American kestrel.

It is probably closely related to and looks like a small version of the orange-breasted falcon. These two, in turn, are probably closest to the aplomado falcon and constitute a rather old American lineage of Falco species.

This small dark bird of prey inhabits open woodlands and forest clearings. Bat falcons perch conspicuously on high, open snags, from which they launch aerial attacks on their prey. They hunt bats, birds, small rodents and large insects such as dragonflies. The smaller male takes more insects, and the female more birds and bats. The flight is direct and powerful. This falcon is partly crepuscular, as the bats in its diet suggest. It lays two or three brown eggs in an unlined treehole nest.

Identification

23–30 cm ; male 108–150 g , wingspan 51–58 cm; female 177–242 g, wingspan 65–67 cm. Small, compact version of F. deiroleucus (though smallest female deiroleucus little bigger than largest female of present species), with slightly broader black breastband more finely barred  , less block-like head, less pure white throat (in South America) and much smaller feet; lacks pale nape of larger and quite differently shaped F. femoralis, which has longer, more clearly barred tail and even narrower wings. Long wings virtually reach tail tip when perched. Head and upperparts blue-black  , with greyish edging to contour feathers from upper back to tail-coverts; throat and upper breast white  , buff or cinnamon, extending to hindneck; rest of breast and underwings black, finely barred white; belly, thighs and undertail-coverts chestnut-rufous  ; rather long tail blackish, with several fine white or greyish bars and white or buff tip. Iris deep to black-brown, cere and orbital ring bright yellow  (sometimes greenish yellow in juvenile) and legs orange-yellow  (paler in juvenile). Female much larger, averaging 18% (6–32%) in size and 64% (20–124%) in mass. Juvenile duller and browner above; throat more buff-coloured; tawny tinge to barring on breast; undertail-coverts with black bars or spots. Races  distinguished by tone of plumage coloration.

Systematics History

In the past, species alternatively labelled F. albigularis. May belong in the F. subbuteo complex (see below). Similarity to F. deiroleucus probably indicates a recent common ancestor, rather than convergence; vocal behaviour unusual among falcons, shared only with latter species. Cladistic analysis of syringeal morphology suggested close relationship with F. femoralis (but deiroleucus not included in taxa sampled) (3). Validity of races petoensis and ophryophanes often challenged, on grounds that they represent clinal variation in plumage darkness (4); on other hand, populations in far N of range (palest of all) sometimes awarded separate race, petrophilus (here subsumed within petoensis); some authors have preferred to recognize two races, petrophilus and nominate (5). Three subspecies currently recognized.

Subspecies

Falco rufigularis petoensis

N Mexico (from Sonora E to Tamaulipas) S through Central America to Colombia and, W of Andes, to Ecuador and extreme NW Peru (6).

Falco rufigularis rufigularis

E Colombia E to the Guianas and Trinidad, and S to E Ecuador, E Peru, N and E Bolivia, S Brazil and N Argentina (to Tucumán).

Falco rufigularis ophryophanes

tableland of C Brazil (Piauí S to Mato Grosso, São Paulo and Paraná) and adjacent Bolivia, Paraguay and NE Argentina.

Distribution

Habitat

Tropical forests, generally from lowlands up to montane forest at 1700 m, with a single record from highlands of La Paz, Bolivia, at c. 3250 m. Fairly adaptable: inhabits unbroken forest, where hunts over canopy; sometimes reported to be more common in more broken forest (disturbed areas, forest edge, road cuts, riverbanks or cleared agricultural land with scattered trees), but this apparent predilection may be result of species being more conspicuous in such areas; observations at one nest suggest preference for foraging over intact forest rather than cleared areas, and the species is speculated to reach highest densities in mosiac of mature forest, young successional forest and abundance of nest and perch sites (2). Sometimes even recorded in urban areas.

Movement

Apparently sedentary, but at least some (perhaps mainly juveniles) wander during non-breeding season, reaching near-shore islands such as Cozumel, off Yucatán Peninsula (Mexico), Islas de la Bahia (Honduras) and perhaps some of Panama’s offshore islands. Just two records from Tobago (breeds on Trinidad). Record from high altitude in Bolivia perhaps also reflects wandering or dispersal.

Diet and Foraging

Mainly bats  , birds  and large insects  . Percentage of birds to bats in diet varies greatly between areas, and the overall contribution of vertebrates to biomass varied from 66% in Guatemala, to 83% (Mexico) and 96% (Venezuela), although numerically invertebrates can be much more important, while the estimated importance of birds varied from 32% in lowland Venezuela to 85% in cloudforest habitat in same country. Wide variety of birds, with 56 species caught by one pair in Venezuela (c. 80% of all items), 35 species in another study (c. 65% of prey biomass) and 83 species at Tikal National Park (Guatemala): taking the different studies, cumulatively most avian prey involved highly aerial species, e.g. swifts, swallows and hummingbirds, but also tanagers, even grebes (1), species as large as White-fronted Amazon (Amazona albifrons) or understorey and forest interior birds including Tody-motmot (Hylomanes momotula), antbirds (Thamnophilidae), manakins (Pipridae) and wrens (Troglodytidae) (2). Insects include dragonflies (Odonata), moths  (Lepidoptera), large grasshoppers (Orthopera), Homoptera and Hymenoptera; in post-fledging period, dragonflies may form c. 40% of prey biomass, but there is considerable individual and temporal variation, thus insects (especially dragonflies) become more prevalent as breeding season progresses, while their overall contribution varied at different nests in Tikal, from 94% of insects at one to just 26–43% at two others. Bats rarely comprise more than 14% of biomass (Mexico), but locally some pairs may be highly specialized on such prey, whereas at Tikal they constituted just 2% of prey. There is an unconfirmed record of this species taking small green fruits. Mostly hunts around dawn and dusk, often well after sunset. Prey almost always taken in air (and small items often consumed on wing), but some rats and geckos caught on ground (although never witnessed during detailed Guatemalan study). From high perch  , will attack birds up to 100 m away moving above canopy, through open areas, or even across road cuts through forest; more rarely hunts from high in air, chasing high flying insects or stooping at prey below. Flies low over canopy trying to flush prey from canopy; one seen flying to canopy tree, clinging to branch while flapping wings for several seconds, and then flying up to catch insects flushed from tree, but during 900 hunts observed in Mexican study, just once observed to snatch prey from foliage . In French Guiana, males and females employ different techniques for catching bats, and study at Tikal found that males take on average larger prey (resulting from the fact that males are responsible for most provisioning during early part of nesting season, when birds are numerically more important constituent of diet) and perform longer-duration hunts (averaging c. 72 seconds versus c. 54 seconds). In this region, success rate was > 71%, as opposed to c. 60% in Mexico, while hunting tactics employed at Tikal were as follows: 12·5% were low above ground, 11·4% were over open areas, 23·9% were directed at the forest canopy, 22·7% were within forest and 18% were well above forest or open ground.

Sounds and Vocal Behavior

Lone birds are generally quiet, but pairs together are highly vocal (2). Gives rapid shrill screaming “kee-kee-kee..  ” or “kew-kew-kew..” (male higher-pitched than female) at rate of c. 2 syllables/second especially around nest and during breeding season, and which becomes an even higher and thinner “tsee-tsee-tsee…”. Also longer “keee-keee-keee…”, a single sharp “kik”, a whining or high-pitched wailing call with a wavering quality (given solely by females and nestlings when food-begging), and low-intensity “chit” given in contact.

Breeding

Most data from E Mexico, with only handful of nesting attempts observed elsewhere. Season seems protracted: in Guatemala (Petén), Belize and Mexico, courtship begins in Feb–Mar (middle of dry season), with laying in Mar–Apr and young fledging mid May to late Jun; on Trinidad, nesting in Feb; in Colombia, birds in breeding condition in Feb–Mar; eggs in Mar in N Venezuela, in Apr in Guyana, and in Aug (middle of dry season) in NC Brazil (Manaus); season probably Oct–Feb in N Argentina. Nests in natural tree cavities  or holes excavated by parrots, in old trogon nests in termite colonies, or on cliffs, usually 10–50 m above ground; also on pre-Columbian ruins, and modern man-made structures, e.g. on sugar mill crane, in Guyana. Usually no material is added. In Guatemala, 19 nests were cavities in dead trees, three in live trees, three on cliffs, two each on palm fronds and in Mayan temples, and one each on steel girders and in old termite colony. Varied and spectacular aerial displays in run-up to breeding. Copulation often preceded by courtship feeding; both parents vocal and aggressive around nest tree, chasing other raptors flying as far as 1 km from nest-tree. Clutch 2–4 eggs (mean 2·9, in Mexico), mean size 40·6 mm × 31·7 mm, mass c. 22 g; no data on incubation period, but estimated at 30 days and males can incubate up to 10–25% of time (Guatemala), although in Mexico females incubated all of time, provisioned by male; young have white or pale greyish-white down and a pale grey cere; fledging c. 35–40 days, but young remain dependent on parents for up to at least 12 weeks post-fledging. Male provides virtually all of food during nestling phase, contributing > 60% throughout nesting period. Breeding success in Mexico: ten of 15 pairs successfully produced young, equating to 1·67 fledged young per nesting attempt (or 2·5 fledglings per successful nest), versus 2·25 and three young, respectively, in Guatemala (from just four nests). Subadult (i.e. younger than two years old) females apparently more likely to breed than young males.

Conservation Status

Not globally threatened (Least Concern). CITES II. Widespread and generally not uncommon in appropriate habitat, it being one of the most widely distributed New World falcons. Very few density estimates, but 0·08 individuals/km² in NW Peru, where species is considered rare (10), while a Mexican study found a mean distance of 1·5 km  between neighbouring pairs. Uncommon in NW Argentina, at S limit of range. Tolerates, and may even benefit from, patchy, small-scale deforestation (although this is uncertain). However, in Middle America no longer breeds in several areas where forest extensively transformed to agriculture, and is only common on Mexico’s Caribbean slope; this trend is likely to be repeated elsewhere throughout range. Further S local extinctions have occurred due to land-use change, specifically deforestation, e.g. in Cauca Valley of Colombia. Usage of pesticides has unquestionably affected breeding success, with 18% eggshell-thinning reported in Mexico, and DDT may have been a factor behind local extirpations in parts of Guatemala and SE Mexico. Range might be more extensive in the south, where recently reported from Santa Catarina, S Brazil.

Fuentes: Wikipedia/eBird/xeno-canto/WikiAves/Bids of the world