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Grey Falcon
Falco hypoleucos

Status: Vulnerable

Population Trend: Stable.

Other Names: Blue Hawk, Gray Falcon, Smoke Hawk.


Falco hypoleucos
click to enlarge
Distribution: Australasian. Eastern AUSTRALIA, Northern Territory (an isolated population in the Top End), TASMANIA, and NEW GUINEA (vagrant). more....

Subspecies: Monotypic.

Taxonomy: The spelling "Grey" is used for the vernacular name to coincide with Australian usage.

Movements: Probably largely sedentary, except in periods of drought, when many birds disperse to the coast or inland refugia. There is clearly a tendency for birds to be further south in the summer and further north in the winter (Baker-Gabb 1984, Olsen and Olsen 1986), and regular movements from west to east are said to occur in Queensland (G. Czechura in Garnett 1992). Immatures and non-paired adults are reported to disperse during the non-breeding season (autumn to spring) toward coastal areas of Queensland and New South Wales (Longmore 1978, Debus 1982), and a comprehensive study from 1986-1990 confirmed that the species is apparently absent from these coastal areas in summer (Baker-Gabb and Steele 1999). It is probable that juveniles migrate north and south more than adults (Debus 1998).

Habitat and Habits: The distribution of the Grey Falcon is centered on inland drainage systems, where it frequents timbered lowland plains, particularly acacia shrublands cross by tree-lined watercourses (Garnett 1992). It also hunts in treeless areas and frequents tussock grassland and open woodland, especially in winter, but it generally avoids deserts (Olsen and Olsen 1986), but Mooney and Holdsworth (1988) reported that in Tasmania it prefers closed forest habitats which provide both concealment and perches for hunting. Grey Falcons spend much time perched in dead or living trees, but also courses over the landscape widely in search of prey, sometimes sweeping low over waterholes (Debus 1998). Quiet and unobtrusive.

Food and Feeding Behavior: Feeds mostly on pigeons and parrots, but also on other birds, small mammals, lizards, and large insects (Marchant and Higgins 1993). It also feeds on carrion, including dead lams (Olsen and Olsen 1986). Forages by low, fast flight, quartering, high soaring, or still-hunting from a perch, seizing prey in flight by a stoop or direct flying attack, or by gliding from a perch to take prey on the ground (Debus 1998). To Olsen (1995), the hunting flight is often hobby-like, at treetop level, zig-zagging at speed down inland watercourses. more....

Breeding: Solitary nester, using the large stick nest of another species, usually a corvid, in the top of a tree 9-25 m above the ground (Debus 1998). Nests are usually in the tallest trees along watercourses, particularly River Red Gum (Marchant and Higgins 1993). Clutch size is usually 2 or 3 eggs, occasionally 4. The incubation period is 35 days, and the nestling period is 41-52 days (Debus op cit.). Nesting may be confined to years of above average rainfall, and the falcons may vacate nesting areas during droughts (T. Aumann in Garnett and Crowley 2000).more....

Conservation: Scarce and possibly declining, owing mostly to habitat degradation, particularly overgrazing of arid zone rangelands, and possibly competition from the peregrine, whose numbers are increasing in Australia (Debus 1998). Olsen (1995) felt that there has been a slight decrease in distribution, but perhaps not a change in status because of the increase in bodies of permanent water. Garnett and Crowley (2000) found no evidence of a general population decline. However, Garnett et al. (2011) recently uplisted this species from Near Threatened to Vulnerable nationally, and BirdLife International (2012) made the same change. The Grey Falcon is categorized as Endangered in New South Wales and Victoria and as Rare in South Australia and Queensland. Debus (2008, 2009) regarded it as the least studied Australian falcon, and, like Garnett and Crowley (op cit.), he recommended that methods be developed to assess population trends and that the population should be monitored. more....

Population Estimates: Garnett and Crowley (2000) estimated the present population size at only 2,000 breeding birds, but they found no evidence of a general population decline.

Important References: 
Schoenjahn, J. 2013. A hot environment and one type of prey: investigating
  why the Grey Falcon (Falco hypoleucos is Australia's rarest falcon. Emu
  113(1):19-25
BirdLife International. 2000. Threatened birds of the world. Lynx Edicions
  and BirdLife International, Barcelona and Cambridge, UK.
Blakers, M., S.J.J.F. Davies, and P.N. Reilly. 1984. The atlas of
  Australian birds. Royal Australasian Ornithologists' Union and Melbourne
  University Press, Melbourne.
Cade, T.J. 1982. Falcons of the world. Cornell University Press, Ithaca,
  NY.
Collar, N.J., and P. Andrew. 1988. Birds to watch: the ICBP world
  check-list of threatened birds. International Council for Bird
  Preservation, Cambridge, UK.
Collar, N.J., M.J. Crosby, and A.J. Stattersfield. 1994. Birds to watch 2:
  world list of threatened birds. Birdlife Conservation Series 4:1-407.
Czechura, G.V., and S.J.S. Debus. 1985. The Grey Falcon Falco hypoleucos:
  a summary of information. Australian Bird Watcher 11:9-16.
Debus, S.J.S. 1994. Grey Falcon. P. 270 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.
Debus, S. 1998. The birds of prey of Australia: a field guide. Oxford
  University Press, Melbourne.
Falkenberg, I.D. 2011. Aspects of the ecology of the Grey Falcon Falco
  hypoleucos
in the South Australian arid zone. Corella 3523-28.
Ferguson-Lees, J., and D.A. Christie. 2001. Raptors of the world. Houghton
  Mifflin, Boston, MA.
Garnett, S.T., and G.M. Crowley. 2000. The Action Plan for Australian
  Birds 2000. Environment Australia, Canberra, Australia.
Hollands, D. 1984. Eagles, hawks and falcons of Australia. Thomas Nelson,
  Melbourne, Australia.
Marchant, S., and P. Higgins (eds.). Handbook of Australian, New Zealand,
  and Antarctic birds. Vol. 2. Raptors to lapwings. Oxford University Press,
  Melbourne, Australia.
Olsen, P. 1995. Australian birds of prey. John Hopkins University Press,
  Baltimore, MD.
Olsen, P.D., and J. Olsen. 1986. Distribution, status, and movements of
  the Grey Falcon, Falco hypoleucos. Emu 86:47-50.
more....

Sites of Interest:
Movements and genetics of Grey Falcons
A site devoted to increasing knowledge of the ecology and biology of the Grey Falcon.

Researchers:
Morley, Mick
Olsen, Penny
Olsen, Jerry
Schoenjahn, Jonny

Last modified: 3/21/2013

Recommended Citation: Global Raptor Information Network. 2014. Species account: Grey Falcon Falco hypoleucos. Downloaded from http://www.globalraptors.org on 17 Apr. 2014








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