A large, rather scruffy-looking kite species, the whistling kite (Haliastur sphenurus) is named for its loud, descending, whistling call. This bird of prey has a relatively small head and slim body, and fairly long wings with long ‘fingers’ at the ends. The tail is also quite long and has a rounded tip (2) (3) (5).
The adult whistling kite is mainly sandy brown, with a lighter brown, pale-streaked head and underparts (2) (3) (5). The secondary feathers of the wing are darker brown and the primary feathers are black (2) (3), while the tail is greyish (2). The pattern on the underside of the wing is quite distinctive, with pale wing linings contrasting with the dark secondary feathers and outer primary feathers, and these two dark areas being separated by a pale patch on the inner primaries (2) (3).
The eyes of the adult whistling kite are brown, while the fleshy cere is pale grey. The whistling kite has short legs which vary from cream to yellowish- or bluish-white (2) (3). The male and female whistling kite are similar in appearance, but the female is usually larger than the male (2) (5). Juveniles are slightly darker than the adults and have paler streaking on the head and underparts, while the upperparts are spotted with buff or white (2) (3) (5).
The whistling kite is easily confused with the similar-looking little eagle (Hieraaetus morphnoides), but has a longer tail and wings, a more slender head and body (2) (3) and a slightly different pattern on the underwings (2).
The distinctive whistling call of the whistling kite has been described as a leisurely, descending ‘seeeo’ or ‘teee-ti-ti’ (2) (5), preceded or followed by a fast, rising chatter of shrill, staccato notes (2) (3). Individuals or pairs often call noisily from the nest or from a prominent perch, standing in an upright posture with the head raised and the beak tilted towards the sky (3).
- Also known as
- whistling eagle, whistling hawk.
- Milvus sphenurus.
- Length: 51 - 59 cm (2) (3)
- Wingspan: 120 - 146 cm (2) (3)
- Male weight: 600 - 750 g (2)
- Female weight: 760 - 1,000 g (2)
Whistling kite biology
The whistling kite has a characteristic lazy, soaring flight (3) (5), and it often calls while flying (3). This species either hunts from a perch or glides and circles above the ground as it searches for prey, sometimes even hovering, albeit clumsily. It often patrols along roads and the edges of grass fires looking for food, and occasionally takes insects in flight or steals food from other birds of prey (2) (3). The whistling kite has a varied diet which includes small mammals, birds, reptiles, frogs, fish, insects and crustaceans. It also feeds on carrion (2) (3) (5). Most prey is taken from the ground or snatched from water (2) (3).
Although usually seen alone or in breeding pairs, the whistling kite sometimes gathers in small flocks at roosts or at abundant food sources (3). The breeding season of this species is variable (3), but generally occurs between July and January in southern parts of its range, and March to October in the north (5). During this time, pairs of whistling kites may soar together and perform acrobatics or mock fights in the air (2) (3).
The nest of the whistling kite is built from sticks and may measure up to 1.5 metres across and 1 metre deep after repeated use year after year. The nest is lined with green leaves, and is generally located in a tall tree or occasionally on a pylon. The female whistling kite lays a clutch of one to four eggs, although two to three is most common. The eggs are incubated for 35 to 40 days, and the young kites leave the nest at about 44 to 54 days old (2) (3). The young are then dependent on the adults for six to eight more weeks (2) (3) (5).
Whistling kite range
The whistling kite is found across much of Australia, although it is uncommon in Tasmania and is generally absent from inland deserts on the mainland. It also occurs in New Caledonia and much of New Guinea, other than in the mountains and in western Irian Jaya (2) (3) (5) (6).
Many populations of the whistling kite are sedentary, remaining in the same area year-round, but others are partially migratory, undertaking seasonal movements between different areas (2) (5).
Whistling kite habitat
Found at elevations from sea level to around 1,400 metres (2), the whistling kite inhabits a range of habitats, from woodland and open forest to savanna, plains and wetlands. It is often found near water, commonly occurring in woodland near lakes, rivers, swamps, estuaries or coasts, but tends to avoid dense forest (2) (3). This species also occurs around farmland and in areas where carrion can be found, such as at rubbish dumps, abattoirs and along roadsides (5).
Whistling kite status
The whistling kite is classified as Least Concern (LC) on the IUCN Red List (1) and is listed on Appendix II of CITES (4).
Whistling kite threats
The whistling kite is widespread and has a large population, and is therefore not currently considered to be threatened (6). This species may have benefitted from forest clearance, and farmland often provides it with suitable hunting grounds and artificial water sources. Road kill also provides the whistling kite with an extra food source (5).
However, populations of the whistling kite in the southern parts of its range appear to be declining due to the drainage of wetlands and a reduction in its food supply (2) (3) (5). The scavenging habits of this bird may also potentially put it at risk from poisoning by agricultural chemicals or baited carcasses (3).
Whistling kite conservation
The whistling kite is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that any international trade in this bird of prey should be carefully regulated (4). This large kite is also protected in Australia under the Environment Protection and Biodiversity Conservation Act 1999 (7), but it is not known to be the target of any other specific conservation measures at present.
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- The flesh of a dead animal.
- In birds, an area of skin at the base of the upper mandible of the beak, surrounding the nostrils.
- Diverse group of animals with jointed limbs and a hard chitinous exoskeleton, characterised by the possession of two pairs of antennae, one pair of mandibles (mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, woodlice and barnacles.
- To keep eggs warm so that development is possible.
- Primary feathers
- In birds, the main flight feathers projecting along the outer edge of the wing.
- Secondary feathers
- The shorter flight feathers projecting along the inner edge of a bird’s wing.
IUCN Red List (November, 2012)
Ferguson-Lees, J. and Christie, D.A. (2001) Raptors of the World. Helm Identification Guides, A&C Black Publishers, London.
Debus, S. (2012) Birds of Prey of Australia: A Field Guide. Second Edition. CSIRO Publishing, Collingwood, Australia.
CITES (November, 2012)
Birds in Backyards - Whistling kite (November, 2012)
BirdLife International - Whistling kite (November, 2012)
Department of Sustainability, Environment, Water, Population and Communities (2012) Haliastur sphenurus. In: Species Profile and Threats Database. Department of Sustainability, Environment, Water, Population and Communities, Canberra. Available at: