[order] FALCONIFORMES | [family] Falconidae | [latin] Falco hypoleucos | [authority] Gould, 1841 | [UK] Grey Falcon | [FR] Faucon gris | [DE] Silberfalke | [ES] Halcon Gris | [NL] Grijze Valk
Members of the genus falco are mostly medium-sized falcons, but vary from the large peregrine falcon to the small American kestrel. The wings are long and pointed and used almost continuously during flight. The bill is short, powerful, and with a distinct ‘tooth’ on each side. Most falcons of this group have a black teardrop-shaped ‘mustache’ mark on each side of the head. Falcons are fastflying birds of open country and are famous for attaining high speeds as they dive from high altitudes to knock birds out of the air.
Typical falcon intermediate in size between Peregrine Falcon Falco peregrinus and Australian Kestrel Falco cenchroides and with loud repeated ‘kek’ call. Overall coloration grey with black primaries. Secondaries grey with 10 dark brown wavy bars. Small black moustachial stripe, with black streaking often around eye. Throat whitish. Underparts may be greyish white. Iris brown; bill bluish and yellow at base; cere orange; legs yellow or yellow-orange
Australasia : Australia. Infrequently seen over much of arid and semi-arid Australia. It may have been eliminated from some breeding areas early in the 20th century, particularly those with more than 500 mm annual rainfall in New South Wales, but the present range is believed to be stable.
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. It also hunts in treeless areas and frequents tussock grassland and open woodland, especially in winter, but it generally avoids deserts, but it is 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; quiet and unobtrusive.
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. Nests are usually in the tallest trees along watercourses, particularly River Red Gum. Clutch size is usually 2 or 3 eggs, occasionally 4. The incubation period is 35 days, and the nestling period is 41-52 days. Nesting may be confined to years of above average rainfall, and the falcons may vacate nesting areas during drought.
Feeds mostly on pigeons and parrots, but also on other birds, small mammals, lizards, and large insects. It also feeds on carrion, including dead lams. 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. The hunting flight is often hobby-like, at treetop level, zig-zagging at speed down inland watercourses.
copyright: Herve Jacob
This species qualifies as Near Threatened because it has a moderately small population in which all mature individuals are in one subpopulation. Although it has experienced a decline and range contraction, its population is now believed to be stable. However, if the species is found to be in decline it might qualify for a higher threat category.
Continued high levels of grazing in arid zone rangelands and clearance of the semi-arid zone for marginal farming is degrading habitat. Localised DDT-related eggshell thinning of up to 15% was detected when this pesticide was legal, but is no longer considered a problem. Nest site availability, particularly in sparsely-treed inland areas, may eventually become a limiting factor, especially where grazing by introduced herbivores is preventing tree regeneration.
Poorly understood; resident and partly migratory or dispersive populations. Some pairs resident except during drought, when may disperse to coast or inland refugia in summer; some birds, possibly mainly juveniles, migrate to winter in Northern Australia.