Stiltia Isabella

The Australian pratincole (''Stiltia isabella'') is a species of bird in the family Glareolidae. It breeds in Australia's interior and winters in northern and eastern parts of the continent, Indonesia and New Guinea. It is a medium-sized nomadic shorebird but is commonly found in arid inland Australia. It breeds predominantly from south-western Queensland to northern Victoria, and through central Australia to the Kimberley region in Western Australia. The Australian population is estimated at 60,000 individuals.

They are a migratory species that generally move to the southern parts of their distribution range to breed during spring and summer. During winter they migrate to northern Australia, New Guinea, Java, Sulawesi and southern Borneo.Geering, A., Agnew, L. & Harding, S. (2007). Shorebirds of Australia. CSIRO Publishing, Collingwood. Although they are common, their occurrence is unpredictable and varies in location.Morcombe, M.(2003). Field guide to Australian birds. Steve Parish Publishing Pty Ltd. Archerfield, Queensland.

Taxonomy

The Australian pratincole belongs to the family Glareolidae. It is monotypic within the genus ''Stiltia''.Chrisitidis, Les and Walter. E. Boles. (2008). Systematics and Taxonomy of Australian Birds. CSIRO Publishing, Collingwood.

Other common names

The pratincole is also known as the Arnhem Land grouse, Australian courser, roadrunner (not to be confused with the genus of North American cuckoos, ''Geococcyx''), nankeen plover and swallow-plover.Higgins, P.J. & Davies, S.J.J.F. (eds) (1996). Handbook of Australian, New Zealand and Antarctic Birds. Volume 3: Snipe to Pigeons. Oxford University Press, Melbourne. .

Description

The Australian pratincole is a medium-sized slender shorebird with long legs, long pointed wings and a short decurved bill. It is long, has a wingspan of and weighs .

The sexes look alike but their breeding and non-breeding plumage differs.

In their breeding plumage, the head, neck, breast and upperparts are a sandy brown grading. The wings are pointed and black and there is a black loral strip. The chin and throat are white and the breast is a sandy brown. The bill is bright red with a black base and the iris is dark brown. Their legs and feet are grey to black.

Their non-breeding plumage is not well known, because there are seasonal and individual variations. The loral stripe is fainter than when in breeding plumage, and the base of the bill is paler. The upper parts are grey-brown with sandy-buff fringes. Sometimes there are dark flecks at the borders of the pale throat.

Juvenile plumage is similar to a non-breeding adult but a slightly paler sandy brown colour. The lores lack the black colour and the forehead, crown and nape are streaked dark brown. The bill is grey-black with a faint reddish base.

In flight, the upper body and inner wing are sandy brown with black on the outer wing. The tail is square-cut, and the upper-tail coverts and sides of the tail are white.

The Australian pratincole is slightly slimmer and smaller in size than oriental pratincole (''Glareola maldivarum''), with longer legs. Juveniles with worn plumage and birds in non-breeding plumage can also be confused with the oriental pratincole.

Habitat and distribution

The habitat of the Australian pratincole is treeless, open and sparsely wooded plains, grasslands, claypans and gibberstone. Most of those areas are in arid and semi-arid rainfall zones. The birds can also be found around the margins of wetlands, creeks, river beds, bore drains, lagoons, springs, claypans and sewage farms. During the breeding season, they inhabit low, scattered shrubland, because the chicks use the vegetation to hide and shelter in.

Behaviour and ecology

Diet

The diet of the Australian pratincole consists mainly of insects, spiders and centipedes. Insects are caught either hawking in the air or pecked from the surface of the ground. When foraging on the ground, the birds stalk their prey, then dart forward to catch the prey, sometimes with one wing outspread. They actively forage during the day, with peak periods at dawn and dusk. They require drinking water because they thermoregulate by evaporation from the mouth. They have salt glands, so both saline and ephemeral water can be drunk.Maclean, G.L (1976). "Field study of the Australian Pratincole" (PDF) Emu 76:171-182

Breeding

They are a monogamous species, with pairs staying together during the breeding season. They usually lay two eggs in a scrape on bare ground. Sometimes, in a dry season, only one egg is laid.G.Beruldsen. p. 224. . Beruldsen, Gordon (2003). Australian Birds: Their Nests and Eggs. Kenmore Hills, Queensland If the ground is soft, the birds will make a shallow depression. The nests are sometimes ringed with small stones or sheep droppings. They are sometimes lined with small pebbles, dry plant material or rabbit droppings. The eggs are light cream to stony brown in colour, with short wavy streaks and irregularly shaped spots of brownish black, intermingled with smaller underlying bluish-grey markings which are evenly distributed . The egg measure approximately 31mm x 24mm.

Both sexes have been observed to incubate the eggs and care for the chicks. The young are semi-precocial and downy, with sandy buff with black markings. At approximately 10 days, feathers start to appear and, at three weeks of age they are fully feathered, with similar colouration to that of a non-breeding adult. The parents continue to feed the young until they are able to fly at four or five weeks.

Migration

They are known to gather in flocks to migrate, and calls heard continuously within the flock.

Sexual behaviour/courtship

When the birds first arrive in the breeding grounds they appear to already be paired. At that time, the birds appear to be maintaining their bonds and possibly enter into courtship rituals. It appears that the nest site selection is part of the pair-bond ritual, with both sexes involved equally. They have been observed running to a spot where one sits down and shuffles its belly and throws small objects sideways. The mate watches, then selects another spot and repeats the ritual.

Family group relations

After hatching, the chicks are led by the parents to nearby cover or refuge. However, some chicks stay in the nest for one day. The parents feed the chicks, flying from up to away with food in their bill. The chicks run out to be fed, probably in response to calls by the parents.

Distraction displays

The Australian pratincole has a repertoire of displays to distract threats, including:
*False-brooding
*Low flight skimming tops of shrubs
*Wings held vertically upwards
*Injury-feigning display away from intruder, showing black and white tail pattern
*Injury-feigning display towards intruder
*Darting about or jumping 20 cm in the air ritualising feeding patterns with or without both wings partly spread.
*Non-vocal sounds- during intense distraction displays, the wings are beaten loudly on the ground accompanied by an intense alarm call.

Voice

The Australian pratincole is known to call during summer thunderstorms. The calls are sweet or plaintive whistles, or very soft and muted trills and loud sharp notes. No difference in calls between males and females has been identified.

Four different types of calls have been clearly identified:
* Flight call — sweet whistling upslurred ' or '. Calls are usually a series of three or four rapidly repeated notes, varying in length, with the tone rising then falling rapidly.
* Far-contact call — plaintive down-slurred '. The call is used between mates from the ground near the nest and also used to call chicks.
* Greeting call — gently trilled ' or short phrase ' which is used during courtship display and when flying to mate.
* Alarm call — loud sharp notes in increasing intensity ', ' and ', accompanied at times by distraction displays.

References

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{{Taxonbar, from1=Q1073618, from2=Q10821880

Glareolidae
Birds of Australia
Birds described in 1816
Taxonomy articles created by Polbot
Taxa named by Louis Pierre Vieillot