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Barred Forest Falcon
Micrastur ruficollis

Status: Lower risk

Population Trend: Declining.

Other Names: Barred Forest-falcon, Cassin's Barred Hawk, Gray-throated Harrier Hawk (guerilla), Northern Wood Falcon, Red-necked Harrier-hawk (ruficollis), Rufous-faced Harrier-hawk (zonothorax).

Micrastur ruficollis
click to enlarge
Distribution: Neotropical. Central MEXICO southern through Central American lowlands to COLOMBIA and west of the Andes to northwestern PERU and east of the Andes in northern VENEZUELA and from eastern PERU and central and eastern BRAZIL (south of the Amazon) to northern ARGENTINA and southern BRAZIL. more....

Subspecies: 6 races. M. r. guerilla: Central MEXICO (Guerrero, San Luis Potosí, Hidalgo, Veracruz) to NICARAGUA; M. r. interstes: COSTA RICA and PANAMA to western COLOMBIA and western ECUADOR; M. r. zonothorax: COLOMBIA and northwestern VENEZUELA south through ECUADOR to BOLIVIA; M. r. concentricus: Southern VENEZUELA, the GUIANAS and Amazonian BRAZIL; M. r. ruficollis: South of Amazonia in BRAZIL, PARAGUAY, and north-central and northeastern ARGENTINA; M. r. olrogi: Northwestern ARGENTINA. more....

Taxonomy: Formerly considered to be conspecific with the Lined Forest Falcon (M. gilvicollis) by Sclater (1918), Peters (1931), Amadon (1964), Brown and Amadon (1968), Meyer de Schauensee (1970), and Blake (1977), but as a separate species by Pinto (1938, 1947, 1964), Hellmayr and Conover (1949), Phelps and Phelps (1958), Meyer de Schauensee (1966), and Haverschmidt (1968). Schwartz (1972) showed that the two species are distinct, based on differences in voice, plumages, soft part colors, and mensural characters, including the wing/tail ratio. They are broadly sympatric throughout Amazonia.

Movements: Probably non-migratory.

Habitat and Habits: Occurs in lowlands and middle elevations, generally staying well hidden low in the understory of humid primary forest, adjacent late second-growth, and dense thickets in semi-open areas. At Tikal National Park, Guatemala, Thorstrom (2000, 2001) found that this species is more dependent upon primary forest than the congeneric Collared Forest Falcon, but in Brazil, it occurs in second-growth and even in cities (Sick 1993). It often flies accipiter-like through forest with speed and agility and avoids crossing openings (Hilty and Brown 1986, Hilty 2003), but is generally less active than an accipiter. It does not soar, and like other members of this genus, it is partly crepuscular. Various observers have commented on the difficulty of locating it from its ventriloquial calls and have commented on its shyness. Others have characterized it as fearless and confiding. more....

Food and Feeding Behavior: Feeds mostly on lizards (Thorstrom 2000), but also takes small birds and nestlings, mice, rats, bats, reptiles, frogs, crabs, and large insects. Thorstrom (1996) also recorded one feeding on the fallen fruits of a "palo de tzol" tree (Tikalia prisca) in Guatemala. This species tends to occupy low, well concealed perches in the forest understory, dashing out to capture prey. It frequently associates with ant-followers and other mixed-species flocks of small birds. Although it will occasionally attack the birds (usually unsuccessfully) following the ants (Slud 1964, Skutch 1971, Robinson 1994), the majority of prey at ant swarms are large insects and other arthropods (Willis et al. 1983). Nunnery and Welford (2002) reported the capture of a hummingbird by one of these forest falcons at a feeder in Ecuador.more....

Breeding: Virtually all that is known about the nesting biology of this species resulted from studies by Russell Thorstrom and his Guatemalan assistants of the nesting population at Tikal National Park, Guatemala from 1988 to 1996 (Thorstrom 2001, 2007, Thorstrom et al. 1990, 2000). Nearly all nests (n = 70) were in natural cavities 10-30 m high in living or dead trees. There were 23 clutches of 2 eggs and 36 clutches of 3 eggs, which were usually laid on alternate days. The eggs are dark reddish-brown and heavily marked with light and dark brown spots. Incubation lasted from 33 to 35 days (n = 6), and nearly all was done by the female. Males brought food to the nest throughout the incubation period and during the early part of the nestling period. Fledging occurred at 35 to 44 days (n = 13), and young dispersed from their natal areas from four to seven weeks after fledging. Nest predation was relatively high, and only 62% of eggs hatched. Seventy-seven percent of hatched nestlings fledged for an average productivity of 1.1 young per nesting attempt. more....

Conservation: Although most regional avifaunal treatments throughout its extensive range have characterized this species as uncommon to fairly common, Russell Thorstrom, who has studied it intensively, regards it as the probably the most common raptor in Neotropical forests. Unquestionably, its abundance is nearly always underestimated by observers unfamiliar with its characteristic vocalizations and its unobtrusive habits. It is categorized globally as a species of "Least Concern" by BirdLife International (2007). more....

Important References: 
Bierregaard, R.O. 1994. Barred Forest-falcon. P. 253 in del Hoyo, J., A.
  Elliott, and J. Sargatal (eds). Handbook of birds of the world. Vol. 2. New
  World vultures to guineafowl. Lynx Edicions, Barcelona, Spain.
Ferguson-Lees, J., and D.A. Christie. 2001. Raptors of the world. Houghton
  Mifflin, Boston, MA.
Schwartz, P. 1972. Micrastur gilvicollis, a valid species sympatric with
  M. ruficollis in Amazonia. Condor 74:399-415.
Thorstrom, R. 2000. The food habits of sympatric forest-falcons during the
  breeding season in northeastern Guatemala. Journal of Raptor Research
Thorstrom, R. 2001. Nest-site characteristics and breeding density of two
  sympatric forest-falcons in Guatemala. Ornitologia Neotropical 12:337-343.
Thorstrom, R. 2007. Home ranges of Barred (Micrastur ruficollis) and
  Collared Forest-falcons during the breeding season in Tikal National Park,
  Guatemala. Ornitologica Neotropical 18:395-405.
Thorstrom, R.K. 2012. Barred Forest Falcon. Pp. 234-249 in D.F. Whitacre
  (ed.), Neotropical birds of prey: biology and ecology of a forest raptor
  community. Cornell University Press, Ithaca, NY.
Thorstrom, R.K., J.D. Ramos, and C.M. Morales. 2000. Breeding biology of
  Barred Forest-falcons (Micrastur ruficollis) in Guatmala. Auk 117:781-786.
Thorstrom, R.K., C.W. Turley, F.G. Ramirez, and B.A. Gilroy. 1990.
  Descriptions of nests eggs and young of the B arred Forest-falcon
  (Micrastur ruficollis) in Guatemala. Condor 92:237-239.

Sites of Interest:
Barred Forest Falcon photos.
Aves de Rapina do Brasil
Species account with emphasis on Brazil.

Albuquerque, Jorge
Gómez, César
Quirós Bazán, Norman
Riba-Hernández, Laura
Thorstrom, Russell
Valdez, Ursula
Vargas G., José de J.
Whittaker, Andrew

Last modified: 5/8/2014

Recommended Citation: Global Raptor Information Network. 2020. Species account: Barred Forest Falcon Micrastur ruficollis. Downloaded from http://www.globalraptors.org on 5 Aug. 2020

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