The grey falcon (''Falco hypoleucos'') is a medium-sized
falcon
Falcons () are birds of prey in the genus ''Falco'', which includes about 40 species. Falcons are widely distributed on all continents of the world except Antarctica, though closely related raptors did occur there in the Eocene.
Adult falcons ...
native to Australia, possibly the rarest.
It is uncommon throughout its range and is currently classified as
Vulnerable
Vulnerable may refer to:
General
* Vulnerability
* Vulnerability (computing)
* Vulnerable adult
* Vulnerable species
Music
Albums
* ''Vulnerable'' (Marvin Gaye album), 1997
* ''Vulnerable'' (Tricky album), 2003
* ''Vulnerable'' (The Used album) ...
.
Taxonomy
The description of the species was published by John Gould, based on a specimen obtained from
Lockier Burges, a pastoralist at
York, Western Australia, who provided it to the collector
John Gilbert.
Gould's description was issued in the fifth volume (1841) of ''
Birds of Australia'', and was accompanied by a lithograph produced by
Elizabeth Gould, rendered shortly before her early death. The specimen obtained from Burges, mentioned in Gilbert's report of September 1839, was later revealed to be an immature bird when another specimen was shot by Gilbert in 1842. This bird, found 60 kilometres north of
Moore River, was larger and paler than the first Gilbert had supplied, and although he thought it may be an older bird he hopefully noted it as a possible new species. The explorer
Charles Sturt also collected two specimens, and these were forwarded to Gould in England. Gould wrote an emended description and commissioned
Henry Constantine Richter to produce a new plate, this was issued in the 1848 volume of the same work.
The specific epithet ''hypoleucos'' is derived from Ancient Greek, literally 'beneath' and 'white' to mean 'whitish'.
Description

The species has mainly grey upperparts and white underparts, darker on the tips of the flight feathers and with a yellow cere. Young birds are darker. Adults have a body length of 30–45 cm and a wingspan of 85–95 cm, and weight 350–600 g. Females are larger.
[Marchant, S.; & Higgins, P.J. (Eds). (1993). '' Handbook of Australian, New Zealand and Antarctic Birds. Vol. 2: Raptors to Lapwings''. Oxford University Press: Melbourne. ][Schoenjahn, J. (2010). Field identification of the Grey Falcon ‘Falco hypoleucos’. ''Australian Field Ornithology'', 27(2), 49-58.] The call of the grey falcon consists of hoarse chattering, clucking and whining sounds, similar to the
peregrine falcon
The peregrine falcon (''Falco peregrinus''), also known as the peregrine, and historically as the duck hawk in North America, is a cosmopolitan bird of prey ( raptor) in the family Falconidae. A large, crow-sized falcon, it has a blue-grey ...
but slower and deeper. Calls include a loud, slow "kek-kek-kek" or "kak-ak-ak-ak".
Both of the collectors of Gould's specimens were effusive in their praise of this falcon's appearance, Sturt's field note says it had a "delicate beauty", and when Gilbert obtained his second specimen in August 1842 he wrote,
Distribution and habitat
The grey falcon is an Australian endemic, usually confined to the arid inland. It inhabits ''Triodia''
grassland
A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...
, ''Acacia''
shrubland
Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity. It ...
, and lightly timbered arid woodland.
[ It has been sighted over most of mainland Australia except for Cape York. Very few have been seen on the Nullarbor Plain and in the Great Victoria, Gibson and Great Sandy Deserts. Most sightings of the grey falcon have been within the arid zones, with annual rainfall less than 500 mm. When they have been occasionally seen outside of these areas, they have been found in similar dry, low altitude, open woodland or grassland. The only times this bird has been seen in different conditions has been along the Queensland coast during drought years. The grey falcon is often seen in family-type groups of an adult pair and usually one (but up to four) first year birds.][Olsen, P. D. (1986). Short communications - Distribution, status, movements and breeding of the Grey Falcon Falco hypoleucos. ''CSIRO'', 47-51.]
In Sturt's notes to his 1845 contribution to Gould's set of specimens, collected at the interior of New South Wales, he commented that the pair were the only individuals to be seen in their seventeen-month exploration of the region. The grey falcon is one of the world's rarest falcons, and possibly the rarest of the Australian falcons, and may also have been historically uncommon.
Ecology
Diet
When sighted and observed, most grey falcons have been seen hunting. They have a habit of eating on the ground, in the open and around inland bores which make them quite easy to observe while eating. From 88% of observations it can be said that their main prey is other birds, followed by small mammals (6%), reptiles (5%) and invertebrates such as locusts and worms (1%). The birds which they feed on usually form flocks and feed on the ground which is typical of birds in arid regions such as parrots and pigeons. Grey falcons have also been sighted with animals such as; a mallee ringneck, a duck, a yellow-rumped thornbill, locusts, snakes, the house mouse
The house mouse (''Mus musculus'') is a small mammal of the order Rodentia, characteristically having a pointed snout, large rounded ears, and a long and almost hairless tail. It is one of the most abundant species of the genus ''Mus''. Althoug ...
, rabbit kittens, lamb carcasses and one has even been seen pursuing a bat.[
]
Nesting
The grey falcon's breeding range has shrunk recently with breeding occurring in the more arid sections of their distribution.[ They breed once a year but may nest twice a year during abundant seasons or may not nest during drought times. Breeding and nesting occur within the distribution range with nests normally being an abandoned stick nest from another species of bird of prey. Nests are often selected in an upright fork, of the top of a tall tree. These can be located in a patch or a belt of timber along a watercourse in dry inland areas. Nests can be used for several years within the nesting season of July to October in the south and April to June in the North. The grey falcon eggs look very similar to the black falcon’s (''Falco subniger'') but are slightly smaller. A clutch size is generally two or three and occasionally four eggs that are oval shaped and 51x38 mm on average.
]
Conservation
The species has very low densities, numbering only 1,000 breeding pairs, but the population may be stable. Continued high levels of grazing in arid zone rangelands and clearance of the semi-arid zone for marginal farming is degrading habitat.[ The grey falcon occurs in several protected areas, including Sturt National Park.]
Analysis of mitochondrial
A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is us ...
COI DNA sequence variation for grey falcons found low genetic diversity, indicating that the species can be managed as a single population. Despite the low genetic diversity, there was no evidence of a recent genetic bottleneck
A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities such as specicide, widespread violen ...
in the species.
Conservation listing
International
The species was previously listed as near-threatened; in 2012 it was uplisted to Vulnerable
Vulnerable may refer to:
General
* Vulnerability
* Vulnerability (computing)
* Vulnerable adult
* Vulnerable species
Music
Albums
* ''Vulnerable'' (Marvin Gaye album), 1997
* ''Vulnerable'' (Tricky album), 2003
* ''Vulnerable'' (The Used album) ...
. Listed on CITES
CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...
Appendix II.
Australian
Grey falcon are listed as endangered on the Australian Environment Protection and Biodiversity Conservation Act 1999
The ''Environment Protection and Biodiversity Conservation Act 1999'' (Cth) is an Act of the Parliament of Australia that provides a framework for protection of the Australian environment, including its biodiversity and its natural and cult ...
.
State of Victoria, Australia
* The grey falcon is listed as threatened on the Victorian Flora and Fauna Guarantee Act (1988). Under this Act, an ''Action Statement'' for the recovery and future management of this species has been prepared.
* On the 2007 advisory list of threatened vertebrate fauna in Victoria, The grey falcon is listed as endangered
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
.
State of Queensland, Australia
* The grey falcon is listed as rare under the Nature Conservation Act 1992
The ''Nature Conservation Act 1992'' is an act of the Parliament of Queensland, Australia, that, together with subordinate legislation, provides for the legislative protection of Queensland's threatened biota.
As originally published, it prov ...
.
State of Western Australia, Australia
* The grey falcon is listed as fauna that is rare or likely to become extinct under the Wildlife Conservation Act 1950.
State of New South Wales, Australia
* The grey falcon is listed as endangered under the NSW Biodiversity Conservation Act 2016.
References
External links
* BirdLife International. (2006). Species factsheet: ''Falco hypoleucos''. Downloaded from http://www.birdlife.org on 9/12/2006
{{Taxonbar, from=Q576912
grey falcon
Endemic birds of Australia
Diurnal raptors of Australia
grey falcon