The hoary-headed grebe (''Poliocephalus poliocephalus'') is a member of the
grebe
Grebes () are aquatic diving birds in the order Podicipediformes . Grebes are widely distributed freshwater birds, with some species also found in marine habitats during migration and winter. Some flightless species exist as well, most notably ...
family. It breeds in southern parts of
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
; it winters throughout the island of
Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
. The bird takes its name from the silvery-white streaking on its black head. It is common in Australia, with a population of about 500,000. Its habitat is similar to that of the
Australasian grebe.
Description
The hoary-headed grebe is a fairly small dark grey and white grebe. It has a brown eye and a black patch under the chin, and a narrow black streak down the back of the neck. During the breeding season the adult's
plumage
Plumage ( "feather") is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, ...
has white streaks over its entire head, giving them the common name of hoary-headed grebe. Juveniles have a white chin and throat and a striped face. Males have two plumage phases: after breeding they lose the buff breast and the white lines on the head, but can usually be identified then by the broad black bar down the
nape
The nape is the back of the neck. In technical anatomical/medical terminology, the nape is also called the nucha (from the Medieval Latin rendering of the Arabic , "spinal marrow"). The corresponding adjective is ''nuchal'', as in the term ''nu ...
.
Distribution and habitat
The hoary-headed grebe is found in all states and territories of Australia. It is generally absent from the central arid regions of
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
. The hoary-headed grebe is usually found away from the shoreline in large open waters, which may be
estuarine
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...
,
brackish
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...
or
freshwater
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
. It can also be found in sheltered coastal seas. It can sometimes be found in New Zealand, where it is much less common than Australia.
Food
The hoary-headed grebe feeds on
aquatic arthropods
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...
, mostly caught by deep diving. This species feeds during the day, and when the light is poor, forages mostly at the water surface.
Breeding
Hoary-headed grebes breed from August to January. The nests are a floating platform of water weeds, similar to that of the
Australasian grebe, and usually some distance out from shore among sparse reeds or other plants, anchored to and at least partly supported by them. A shallow depression on top is just slightly above water, so the eggs are lying in water or dampness. The eggs are concealed under pieces of wet vegetation when the incubating parent leaves so that the nest appears empty. Under full sun the covered eggs are warm and moist, often left unattended for some time. The egg's appearance is oval, white, and soon stained brownish
ochre
Ochre ( ; , ), or ocher in American English, is a natural clay earth pigment, a mixture of ferric oxide and varying amounts of clay and sand. It ranges in colour from yellow to deep orange or brown. It is also the name of the colours produced ...
, while the clutch is usually 2–5 eggs.
Incubation is 20–24 days and egg size is 39 x 27 mm.
[Morcombe, M. (2003) ''Field Guide to Australian Birds: Australia's Most Comprehensive Guide''. Steve Parish Publishing, Sydney.]
Conservation
With a large range and no evidence of significant population decline, this species’ conservation status is of
Least Concern
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...
.
References
* ''Grebes of the World'' – Malcolm Ogilvie & Chris Rose
{{Taxonbar, from=Q904167
hoary-headed grebe
The hoary-headed grebe (''Poliocephalus poliocephalus'') is a member of the grebe family. It breeds in southern parts of Australia; it winters throughout the island of Tasmania. The bird takes its name from the silvery-white streaking on its bl ...
Birds of Western Australia
Birds of South Australia
Birds of New South Wales
Birds of Victoria (Australia)
Birds of Tasmania
Endemic birds of Australia
hoary-headed grebe
The hoary-headed grebe (''Poliocephalus poliocephalus'') is a member of the grebe family. It breeds in southern parts of Australia; it winters throughout the island of Tasmania. The bird takes its name from the silvery-white streaking on its bl ...
Taxa named by Sir William Jardine
hoary-headed grebe
The hoary-headed grebe (''Poliocephalus poliocephalus'') is a member of the grebe family. It breeds in southern parts of Australia; it winters throughout the island of Tasmania. The bird takes its name from the silvery-white streaking on its bl ...
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