Whistling Kite

The Whistling Kite, scientifically known as Haliastur sphenurus, is a medium-sized raptor gracing the skies of Australia, New Caledonia, and parts of New Guinea. This diurnal bird of prey, also referred to as the whistling eagle or hawk, is distinguished by its buff head, breast, and tail, contrasted with browner wings and stark black flight feathers. Adults exhibit a pale buff plumage, while juveniles are streaked reddish-brown with pale wing spots. Both sexes share the same plumage, and the species is characterized by a small head, long tail, and bone-colored, unfeathered legs.

Identification Tips

When perched, the Whistling Kite's wingtips fall notably short of the tail tip. In flight, it soars on slightly bowed wings, with long flight feathers often splayed, revealing a striking underwing pattern. Females are typically larger than males, with a size range of 50 to 60 cm in length and a wingspan of 123 to 146 cm. Weights vary from 380 to 1,050 grams, with females reaching up to 42% heavier than males.

Habitat

The Whistling Kite favors open or lightly wooded areas, often found near water bodies from sea level up to 1400 meters in elevation. It is generally sedentary, though some Australian populations exhibit nomadic tendencies or seasonal migrations.

Distribution

This species is widespread throughout Australia, including coastal islands, and extends to New Caledonia and much of New Guinea, with the exception of the central mountains and northwest regions.

Behaviour

Typically solitary or in pairs, Whistling Kites may congregate in larger groups during nomadic movements, at roost sites, or where food is abundant. They are known for their adaptability, often seen patrolling roads for roadkill or hovering at the edges of grass fires to capture fleeing prey.

Song & Calls

The Whistling Kite is vocal, with a signature descending whistle that may be followed or preceded by a series of rising notes. This call is a common sound in its habitat, heard both in flight and while perched.

Breeding

Nesting in tall trees, often eucalypts or pines near water, the Whistling Kite constructs a bulky platform of sticks lined with green leaves. The species exhibits high fidelity to nesting sites, reusing and adding to the same nest annually. Clutch sizes range from 1 to 4 bluish-white eggs, with a 60% hatching success rate. Chicks fledge after 44 to 54 days and remain dependent on their parents for an additional 6 to 8 weeks.

Similar Species

While some authorities suggest placing the Whistling Kite in the genus Milvus, it is distinct in behavior, voice, and plumage from other members of that genus.

Diet and Feeding

An opportunistic feeder, the Whistling Kite's diet includes small mammals, birds, fish, reptiles, amphibians, crustaceans, insects, and carrion. It is known to scavenge in New Guinea and actively hunt live prey in Australia, occasionally pirating food from other birds or forcing waterbirds to regurgitate their catches.

Conservation status

The Whistling Kite is currently listed as Least Concern on the IUCN Red List, although there is evidence of local declines in southern Australia due to habitat changes and reduced food availability.