Australasian grebe (Tachybaptus novaehollandiae)

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Australasian grebe fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Australasian grebe description

Australasia’s smallest grebe species ⁽³⁾, the Australasian grebe (Tachybaptus novaehollandiae) is a dumpy waterbird with a blunt-ended body ^{(3) (4)}. It has a short, stout bill and neck ⁽³⁾, with a white or yellow patch of skin between the eye and the bill which contrasts starkly with its glossy black head and neck ^{(3) (4) (5)}. The Australasian grebe has a broad band of rich chestnut behind its eyes and on the sides of its neck ^{(2) (3) (4) (5)}, and its eyes are yellow or orange ^{(2) (4) (5)}.

In its non-breeding plumage, the Australasian grebe is dark brown or dark grey-brown on its upperparts ^{(3) (5)} and silver-grey below ⁽³⁾, and it lacks the chestnut markings of the breeding adult ^{(2) (5)}. The cheeks and foreneck are pale or whitish ^{(2) (5)}, and contrast strongly with the dark brown cap. The white or yellow skin patch near the bill becomes harder to see during the non-breeding season ^{(4) (5)}.

Male and female Australasian grebes are similar in appearance, although males are generally heavier than the females ⁽³⁾, while the juvenile Australasian grebe looks much like the non-breeding adult, except that its head and neck are striped black and white. The different subspecies of Australasian grebe all vary slightly in size and colouration ⁽²⁾.

Despite being a small bird, the Australasian grebe is said to have an explosive call, described as a tittering trill which is repeated at irregular intervals ⁽⁴⁾.

Also known as

Australasian little grebe, Australian dabchick, Australian grebe, black-throated grebe, dabchick, Eastern little grebe.

Size

Length: 23 - 27 cm ⁽²⁾

Wingspan: 39 cm ⁽³⁾

Weight

100 - 230 g ^{(2) (3)}

Australasian grebe biology

The Australasian grebe can often be found roosting on the water in pairs, families or small groups ⁽³⁾. This species is able to swim both high and low in the water ⁽⁴⁾ and is a frequent diver ⁽⁵⁾, often disappearing underwater in search of food ⁽⁴⁾. When disturbed, it may lurk within vegetation, with nothing but its head poking above the surface ⁽⁵⁾.

The Australasian grebe’s diet is relatively varied, and includes small fish, spiders, aquatic insects and their larvae, crustaceans, and freshwater molluscs such as snails ^{(2) (3) (9)}. However, this small bird is also known to feed on vegetable matter, including grass seeds ^{(3) (9)}, and has even been recorded consuming frogs ⁽³⁾. Commonly foraging near submerged or floating vegetation or at the edges of reed beds ⁽³⁾, the Australasian grebe catches its prey either through surface chases or by performing deep dives. This species is also known to associate with other waterbirds, capturing the insects and other invertebrates that these birds flush out ⁽²⁾.

It is thought that the Australasian grebe’s breeding season is stimulated by flooding ⁽³⁾, and it is known to be prolonged as a result of opportunistic breeding on temporary wetlands. However, on permanent waters of south-eastern Australia, this species breeds primarily in the spring ^{(2) (3)}, with egg laying occurring between September and November ⁽²⁾.

The Australasian grebe is a territorial species that breeds in solitary pairs ^{(2) (3)}. Nesting occurs in the water, usually among submerged, emergent or overhanging vegetation ⁽³⁾, and the nest consists of a small, floating platform made from plant material. The female Australasian grebe usually produces four or five eggs per clutch ^{(2) (3)}, and the eggs are laid within a small depression in the centre of the nest ⁽³⁾. The eggs are then incubated by both the male and the female Australasian grebe for a period of about 23 days ^{(2) (3)}. By eight weeks old, the chicks are independent from the adults, although it is not known at what age the young birds become capable of flight ⁽³⁾. A female Australasian grebe can produce two or three broods per breeding season ⁽²⁾.

Australasian grebe range

The Australasian grebe has a wide distribution in Australia ^{(3) (6)}, and is found in most parts of the country, including Tasmania ^{(2) (7) (8)}. However, it is not usually found in the drier, arid regions ⁽³⁾. This species also occurs in parts of the south-western Pacific ⁽⁷⁾ and south-western Oceania ⁽⁸⁾, including New Guinea, New Caledonia, Vanuatu, the Solomon Islands and New Zealand ^{(6) (7) (8)}. The Australasian grebe has also been reported in Indonesia ^{(6) (8)}, although it is thought to be a vagrant there ⁽⁸⁾.

There are seven different subspecies of Australasian grebe, each occupying a different part of the species’ range ^{(2) (4)}.

The movements of the Australasian grebe are poorly known. It is thought to be resident in eastern and south-western Australia, but migratory in the north. As this species colonised New Zealand relatively recently, it is believed to be capable of extensive movements, with ringing records showing that it can travel up to 338 kilometres ⁽²⁾.

Australasian grebe habitat

The Australasian grebe occurs in a wide variety of wetland habitats, although it prefers areas of shallow, permanent or semi-permanent freshwater ^{(2) (3)}. This species is typically found in marshes, swamps, ponds, lakes and even small reservoirs on farms ^{(2) (5) (4) (8)}, particularly in areas with waterside or floating vegetation ^{(2) (4) (7)}.

Australasian grebe status

The Australasian grebe is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Australasian grebe threats

With an extremely large range ⁽⁶⁾, and in the absence of any major threats to the species, the Australasian grebe is not considered to be globally threatened ⁽²⁾.

However, some of the island-based subspecies, such as Tachybaptus novaehollandiae javanicus and Tachybaptus novaehollandiae timorensis, have very small populations, and so may be at risk. Although generally common in Australia, the Australasian grebe has suffered some local declines and even extinctions as a result of human modification of its habitats, such as the drainage and exploitation of underground water supplies ⁽²⁾.

Australasian grebe conservation

As the Australasian grebe is not considered to be globally threatened, there are currently no known conservation measures in place specifically targeting this species. However, as it is reliant on wetland habitats, it is thought that the widespread creation of artificial wetland areas has benefitted this small Australasian species ⁽²⁾.

Find out more

Find out more about the Australasian grebe:

• BirdLife International - Australasian grebe:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=3629

Learn more about bird conservation in Australia:

• BirdLife Australia:
  http://www.birdlife.org.au/

Find out more about conservation in Australia:

• Australian Wildlife Conservancy:
  http://www.australianwildlife.org/
• Australian Conservation Foundation:
  http://www.acfonline.org.au/

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Glossary

Crustaceans

Diverse group of animals with jointed limbs and a hard external skeleton, 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.

Emergent

Aquatic plants whose stems and leaves extend beyond the water’s surface.

Incubate

To keep eggs warm so that development is possible.

Invertebrates

Animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.

Larva

Immature stage in an animal’s lifecycle, after it hatches from an egg and before it changes into the adult form. Larvae are typically very different in appearance to adults; they are able to feed and move around but are usually unable to reproduce.

Molluscs

A diverse group of invertebrates, mainly marine, that have one or all of the following: a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

Territorial

Describes an animal, a pair of animals or a group that occupies and defends an area.

Vagrant

An individual found outside the normal range of the species.

References

1. IUCN Red List (November, 2012)
   http://www.iucnredlist.org/
2. del Hoyo, J., Elliott, A. and Sargatal, J. (1992) Handbook of the Birds of the World. Volume 1: Ostrich to Ducks. Lynx Edicions, Barcelona.
3. Rogers, K. and Ralph, T. (2010) Floodplain Wetland Biota in the Murray-Darling Basin: Water and Habitat Requirements. CSIRO Publishing, Collingwood, Australia.
4. Dutson, G. (2012) Birds of Melanesia: Bismarcks, Solomons, Vanuatu, and New Caledonia. A&C Black Publishers Ltd., London.
5. Robertson, H. and Heather, B. (2001) Hand Guide to the Birds of New Zealand. Oxford University Press, Oxford.
6. BirdLife International - Australasian grebe (November, 2012)
   http://www.birdlife.org/datazone/speciesfactsheet.php?id=3629
7. Thomas, R., Thomas, S., Andrew, D. and McBride, A. (2011) The Complete Guide to Finding the Birds of Australia. CSIRO Publishing, Collingwood, Australia.
8. Sibley, C.G. and Monroe Jr, B. (1991) Distribution and Taxonomy of Birds of the World. Yale University Press, Connecticut.
9. Barker, R. and Vestjens, W. (1989) Food of Australian Birds 1. Non-passerines. CSIRO Publishing, Collingwood, Australia.