Whistling Kite
Encyclopedia
The Whistling Kite is a medium-sized diurnal
raptor
found throughout Australia
(including coastal islands), New Caledonia
and much of New Guinea
(excluding the central mountains and the northwest). Also called the Whistling Eagle or Whistling Hawk, it is named for its loud whistling call, which it often gives in flight
. Some authorities put this species in the genus
Milvus
, despite marked differences in behaviour, voice
and plumage
between this species and other members of that genus.
The Whistling Kite ranges in size from 50 –, with a wingspan
between 123 –. Weights range from 380 –. As with most raptors, female
s are larger and heavier than male
s; though there is considerable overlap between the sexes, females can be up to 21% larger and 42% heavier. Southern birds are also larger than those found in the tropics. Male and female plumages are the same. Adult birds are a pale buff on the head, breast and tail, with browner wings and black flight feather
s. Immature birds are a heavily streaked reddish-brown with prominent pale spots on the wings. Throughout their lives, Whistling Kites have bone-colored legs and feet, which are unfeathered. Overall, the Whistling Kite looks small-headed and long-tailed, with wingtips falling well short of the tail tip when the bird is perched. Though its legs are short, the bird walks easily on the ground. Whistling Kites soar on slightly bowed wings, with their long flight feathers often well-splayed. The striking pattern on their underwings is distinctive.
. Its most common call is a clear descending whistle, often followed (less often preceded) by a rapid series of rising notes. Intriguingly, field research carried out in Taunton Scientific National Park
, Central Queensland
by Fiona Randall from the University of Edinburgh
, Scotland
has shown that Spotted Bowerbird
s (Chlamydera maculata) in that park regularly mimic the calls of Whistling Kites, with the frequency of mimicry increasing as the breeding season progresses. The function of this mimicry is unknown.
; some south Australian birds migrate to the south in the autumn. There is some evidence that the species is declining locally in southern Australia due to the drainage of wetlands and an accompanying decline in food supplies.
Whistling Kites are truly catholic in their tastes, taking small mammal
s, bird
s, fish
, reptile
s, amphibian
s, crustacean
s, insect
s and carrion
. Those in Australia tend to take primarily live prey (except in the winter, when they subsist largely on carrion), while those in New Guinea are principally scavenger
s. Most food items are taken either from the ground or from the water surface, though insects are sometimes hawked directly from the air. Whistling Kites are also known to pirate meals
from ibis
es and heron
s and from other raptors, and to force large waterbirds to regurgitate their catches. They regularly patrol roads in search of roadkill, and hover over the edges of grass fires in search of potential prey fleeing the flames.
—often a eucalypt
or pine
in a riparian area. Pairs often re-use the same nest year after year, annually adding material until the platform becomes quite large. Females normally lay 2–3 bluish-white eggs
, which are sometimes covered with reddish-brown blotches; clutches of 1–4 eggs have been recorded. Eggs are incubated for 35–40 days, and the species is reported to have a 60% hatching success. Chicks, which are covered with cream- or buff-colored down feathers, spend 44–54 days in the nest before fledging, and are dependent on their parents for a further 6–8 weeks after leaving the nest. In Australia, the birds generally breed between June and October in the south, and between February and May in the north, though they may nest at any time after rain providing there are adequate food supplies.
Diurnal animal
Diurnality is a plant or animal behavior characterized by activity during the day and sleeping at night.-In animals:Animals that are not diurnal might be nocturnal or crepuscular . Many animal species are diurnal, including many mammals, insects, reptiles and birds...
raptor
Bird of prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....
found throughout Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
(including coastal islands), New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...
and much of New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
(excluding the central mountains and the northwest). Also called the Whistling Eagle or Whistling Hawk, it is named for its loud whistling call, which it often gives in flight
Bird flight
Flight is the main mode of locomotion used by most of the world's bird species. Flight assists birds while feeding, breeding and avoiding predators....
. Some authorities put this species in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Milvus
Milvus
Milvus is a genus of medium-sized birds of prey. It is an Old World group consisting of three kites which form part of the subfamily Milvinae...
, despite marked differences in behaviour, voice
Bird song
Bird vocalization includes both bird calls and bird songs. In non-technical use, bird songs are the bird sounds that are melodious to the human ear. In ornithology and birding, songs are distinguished by function from calls.-Definition:The distinction between songs and calls is based upon...
and plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
between this species and other members of that genus.
Description
Wingspan
The wingspan of an airplane or a bird, is the distance from one wingtip to the other wingtip. For example, the Boeing 777 has a wingspan of about ; and a Wandering Albatross caught in 1965 had a wingspan of , the official record for a living bird.The term wingspan, more technically extent, is...
between 123 –. Weights range from 380 –. As with most raptors, female
Female
Female is the sex of an organism, or a part of an organism, which produces non-mobile ova .- Defining characteristics :The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male...
s are larger and heavier than male
Male
Male refers to the biological sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. Each spermatozoon can fuse with a larger female gamete or ovum, in the process of fertilization...
s; though there is considerable overlap between the sexes, females can be up to 21% larger and 42% heavier. Southern birds are also larger than those found in the tropics. Male and female plumages are the same. Adult birds are a pale buff on the head, breast and tail, with browner wings and black flight feather
Flight feather
Flight feathers are the long, stiff, asymmetrically shaped, but symmetrically paired feathers on the wings or tail of a bird; those on the wings are called remiges while those on the tail are called rectrices . Their primary function is to aid in the generation of both thrust and lift, thereby...
s. Immature birds are a heavily streaked reddish-brown with prominent pale spots on the wings. Throughout their lives, Whistling Kites have bone-colored legs and feet, which are unfeathered. Overall, the Whistling Kite looks small-headed and long-tailed, with wingtips falling well short of the tail tip when the bird is perched. Though its legs are short, the bird walks easily on the ground. Whistling Kites soar on slightly bowed wings, with their long flight feathers often well-splayed. The striking pattern on their underwings is distinctive.
Voice
This is a noisy species, calling regularly in flight and while perched—even while at the nestBird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
. Its most common call is a clear descending whistle, often followed (less often preceded) by a rapid series of rising notes. Intriguingly, field research carried out in Taunton Scientific National Park
Taunton National Park
Taunton is a scientific national park in Australia, 130 km west of Rockhampton, Queensland....
, Central Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
by Fiona Randall from the University of Edinburgh
University of Edinburgh
The University of Edinburgh, founded in 1583, is a public research university located in Edinburgh, the capital of Scotland, and a UNESCO World Heritage Site. The university is deeply embedded in the fabric of the city, with many of the buildings in the historic Old Town belonging to the university...
, Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
has shown that Spotted Bowerbird
Spotted Bowerbird
The Spotted Bowerbird is a bowerbird widely distributed across inland Queensland and New South Wales.-Australia:...
s (Chlamydera maculata) in that park regularly mimic the calls of Whistling Kites, with the frequency of mimicry increasing as the breeding season progresses. The function of this mimicry is unknown.
Habitat
A species of open or lightly wooded areas, Whistling Kites are typically found near water, at elevations ranging from sea level to 1400 meters. Though the species as a whole is generally sedentary, some Australian birds are known to be nomadic, wandering to coastal areas in northern Australia during the dry seasonDry season
The dry season is a term commonly used when describing the weather in the tropics. The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year...
; some south Australian birds migrate to the south in the autumn. There is some evidence that the species is declining locally in southern Australia due to the drainage of wetlands and an accompanying decline in food supplies.
Behaviour
Whistling Kites tend to be found singly or in pairs, but sometimes gather in larger groups, particularly during nomadic movements, at roost sites and at sources of plentiful food.Feeding
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s, bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s, fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
, reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
s, amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
s, crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s and carrion
Carrion
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...
. Those in Australia tend to take primarily live prey (except in the winter, when they subsist largely on carrion), while those in New Guinea are principally scavenger
Scavenger
Scavenging is both a carnivorous and herbivorous feeding behavior in which individual scavengers search out dead animal and dead plant biomass on which to feed. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by...
s. Most food items are taken either from the ground or from the water surface, though insects are sometimes hawked directly from the air. Whistling Kites are also known to pirate meals
Kleptoparasitism
Kleptoparasitism or cleptoparasitism is a form of feeding in which one animal takes prey or other food from another that has caught, collected, or otherwise prepared the food, including stored food...
from ibis
Ibis
The ibises are a group of long-legged wading birds in the family Threskiornithidae....
es and heron
Heron
The herons are long-legged freshwater and coastal birds in the family Ardeidae. There are 64 recognised species in this family. Some are called "egrets" or "bitterns" instead of "heron"....
s and from other raptors, and to force large waterbirds to regurgitate their catches. They regularly patrol roads in search of roadkill, and hover over the edges of grass fires in search of potential prey fleeing the flames.
Breeding
The Whistling Kite’s nest is a bulky platform made of sticks and lined with green leaves, placed in an upright fork of a tall treeTree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
—often a eucalypt
Eucalypt
Eucalypts are woody plants belonging to three closely related genera:Eucalyptus, Corymbia and Angophora.In 1995 new evidence, largely genetic, indicated that some prominent Eucalyptus species were actually more closely related to Angophora than to the other eucalypts; they were split off into the...
or pine
Pine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...
in a riparian area. Pairs often re-use the same nest year after year, annually adding material until the platform becomes quite large. Females normally lay 2–3 bluish-white eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
, which are sometimes covered with reddish-brown blotches; clutches of 1–4 eggs have been recorded. Eggs are incubated for 35–40 days, and the species is reported to have a 60% hatching success. Chicks, which are covered with cream- or buff-colored down feathers, spend 44–54 days in the nest before fledging, and are dependent on their parents for a further 6–8 weeks after leaving the nest. In Australia, the birds generally breed between June and October in the south, and between February and May in the north, though they may nest at any time after rain providing there are adequate food supplies.