|Australian Bush Birds|
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|Australasian Darter - Anhinga novaehollandiae|
|Male Australasian Darter with wings spread out in the sun; the bird is black overall with a white streak along the neck and pale grey streaks on wing and tail. Camden Haven River at North Haven|
|Female Australasian Darter with wings spread out; wings are black underneath, the body is pale grey below and grey/brown above. Yellow River, Kakadu Nat Pk.|
The Australasian Darter - Anhinga novaehollandiae - is a medium-size water bird (85 to 90 cm long, span to 1.2 metres). Long, sinuous neck with small, sleek head and straight, dagger-like yellow bill. Male and female are differently coloured.
Frequently swims with only the sinuous neck and narrow, tapering head above the water giving rise to the name "Snake Bird"
|Australasian Darter - page 2|
Males are almost entirely gloss black. The head is marked with a white stripe below the eye extending along the side of the neck from the base of the bill, passing under the eye and ending level with the throat. Naked skin around the eye and on the chin. Bill is brown above and yellow below; eye brown. Front of the neck is black with rusty-brown patch decreasing with age. Wing leading edge is black with grey buff behind/below the black. Feet cream to grey-brown. Long rounded tail is grey buff.
Breeding males have chestnut neck markings and long, pointed plumes on the upper wing.
Females are grey-brown above. The stripe on the side of the head has dark edges. Upper wing is pale grey. Underside (throat and breast down to the legs is creamy-white.
During courtship the upper mandible and the tip of the lower mandible become light green in males and females and the feet become cream-white.
Immature birds are like pale coloured females with greyish necks; the stripe on the head is less distinct. Naked skin around the eye and on the throat is pale yellow to orange. Legs and feet are pink, grey, light brown or dark brown. Young males develop a black neck with whitish belly.
Frequents large, shallow, salt or fresh, water submerging for up to a minute at a time and surfacing for a few seconds between dives. Lives in lakes, rivers, swamps and estuaries; in wetlands where water depth is greater then 0.5 metres and there are trees, logs and well-vegetated banks. Rarely in marine habitats. Tiny prey, such as insects, is swallowed during swimming but a larger prey item is speared underwater with the beak then returns to the surface to juggle the prey until it is swallowed head first. Large items may require up to 20 minutes of manipulation and may be taken to a perch.
|Left; Male Australasian Darter at Bundaberg; note the black feathers overall with black neck and white side streak.|
Right; Male Darter resting under water with head and neck above the surface at Fogg Dam, near Darwin. The chestnut patch on the breast of breeding males has extended up the throat, white streak and black at back of head and neck are unchanged.
|Left; Head of female Australasian Darter. The white streak along the neck is visible, while the overall colour is closer to grey than black. The pointed beak is the same as the male's|
Right; Young Australasian Darter yet to grow feathers on the body. Flesh coloured web feet grasping the perch are typical; young darters have head and neck colouring similar to adult females with often less prominent neck stripe.
|Australasian Darter - page 3|
Unlike most waterbirds Australasian Darter plumage is not waterproof and soon becomes saturated once the bird enters the water. Having saturated feathers is presumed to reduce buoyancy so manoeuverability under water is improved. After getting thoroughly wet Australasian Darters are commonly seen standing on rocks and piles with wings spread out drying in the sun.
Juveniles are paler with white undersides. The neck stripe is less distinct.
Frequently seen in solitary perches near water with wings outstretched to dry. Often in water floating very low with only the head showing; disappears below the surface easily with no ripples. Hunts underwater using the beak as a spear by forcefully straightening the kinked neck. Frequently with cormorants. Common in suitable habitats.
Breeds mainly in spring and summer but breeding birds may be found at any time of the year. The nest is a rough platform of coarse twigs with leafy branches drooping from the sides and lined with a few leaves, built in a tree above water. A nest may be used for several years.
Usually four eggs are laid (sometimes five or six); chalky white tinged with green; oblong-oval, 53 to 64 by 35 to 43 millimetres. Incubated for 26 to 30 days by both parents. Young fledge in about 50 days.
¶ Genus Anhinga is in Family Anhingidae. The Darter is found worldwide and various naming schemes have been used over time. Until fairly recently the Darter in Australia was described as subspecies novaehollandiae of Anhinga melanogaster with the English name Darter. After more DNA related investigation the Australian bird is named Anhinga novaehollandia with the English name Australasian Darter acknowledging that the species is found in Australia, New Zealand and parts of Indonesia (the Lesser Sundas and the southern Moluccas).