Hardhead

{{Short description|Species of duck}} {{Other uses}} {{Speciesbox | name = Hardhead | image = Aythya australis female - Hurstville Golf Course.jpg | image_caption = Female | image2 = Aythya australis male - Hurstville Golf Course.jpg | image2_caption = Male | status = LC | status_system = IUCN3.1 | status_ref = <ref name="iucn status 12 November 2021">{{cite iucn |author=BirdLife International |date=2017 |title=''Aythya australis'' |volume=2017 |article-number=e.T22680387A112385790 |doi=10.2305/IUCN.UK.2017-1.RLTS.T22680387A112385790.en |access-date=12 November 2021}}</ref> | genus = Aythya | species = australis | authority = ([[Thomas Campbell Eyton|Eyton]], 1838) | subdivision_ranks = Subspecies | subdivision = * ''A. a. extima'' ([[Ernst Mayr|Mayr]], 1940) (disputed) * ''A. a. australis'' (Eyton, 1838) | synonyms = ''Nyroca australis'' Eyton, 1838 }}

The '''hardhead''' ('''''Aythya australis'''''), also known as the '''white-eyed duck''', is the only true [[diving duck]] found in Australia. The common name "hardhead" has nothing to do with the density of the bird's skull, instead referring to the difficulty encountered by early [[Taxidermy|taxidermists]] in processing the head.<ref name=BA>{{cite web |url=https://birdlife.org.au/bird-profile/Hardhead |title=Hardhead: ''Aythya australis'' |publisher=Birdlife Australia |access-date=9 February 2021 |archive-date=18 March 2022 |archive-url=https://web.archive.org/web/20220318005257/https://www.birdlife.org.au/bird-profile/hardhead }}</ref> Hardheads are found in wetter, coastal regions of Australia, particularly in the south-east, but are known to disperse as far afield as [[New Guinea]], [[New Zealand]], and the [[Pacific Islands]].<ref name="Distribution">{{cite journal |title=Hardhead: ''Aythya australis'' |last1=Carboneras |first1=C. |last2=Kirwan |first2=G.M. |editor1-first=Josep |editor1-last=Del Hoyo |editor2-first=Andrew |editor2-last=Elliott |editor3-first=Jordi |editor3-last=Sargatal |editor4-first=David |editor4-last=Christie |editor5-first=Eduardo |editor5-last=De Juana |journal=Birds of the World |year=2020 |publisher=Cornell Lab of Ornithology |doi=10.2173/bow.wheduc1.01 |s2cid=226085401 }}</ref>

== Description == Hardheads are smaller than most [[duck]]s, with body length typically between {{Convert|42-59|cm|abbr=on}}. Both sexes are similar in size, ranging {{Convert|525-1100|g|abbr=on}} with wingspans of {{Convert|65-70|cm|abbr=on}}.<ref>Carboneras, C. and G. M. Kirwan (2020). Hardhead (''Aythya australis''), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. <nowiki>https://doi.org/10.2173/bow.wheduc1.01</nowiki></ref> Both male and female are a fairly uniform chocolate-brown above, with rufous flanks and white undersides (which are often not visible if the duck is in the water). The trailing edges and almost the entire underside of the wings are white. In the male, the eyes are a striking white, in the female, brown.<ref name=BA/><ref name=Backyards/>

== Distribution and habitat == Hardheads are common in the south-east of Australia, particularly in the [[Murray-Darling Basin]], but also in the wetter country near the coasts.<ref name=Backyards/> They are moderately nomadic in normal years, but disperse widely in times of [[drought]]. Significant numbers reach as far afield as New Guinea, New Zealand, and the islands of the Pacific, where they can remain for some time, even breeding for a season or two.<ref name="Distribution"></ref>

Hardheads prefer larger lakes, swamps and rivers with deep, still water, but are often seen in smaller streams, flooded grasslands, and shallow pools. As a general rule, they avoid coastal waters.<ref name=Backyards/> They rarely come to land and never perch in trees.

Widespread throughout its large range, the hardhead is evaluated as [[Least Concern]] on the [[IUCN Red List of Threatened Species]].<ref name="iucn status 12 November 2021" />

== Behaviour == Like the other members of the [[pochard]] group, hardheads feed by diving deeply, often staying submerged for as long as a minute at a time. They slip under the water with barely a ripple, simply lowering their heads and thrusting with their powerful webbed feet. They eat a broad range of small aquatic creatures, and supplement this with water weeds.<ref name=Backyards/>

Hardheads are usually silent, but males have a soft, wheezy whistle and 'whirr'. Females have a loud rattling 'gaark' call.<ref name=Backyards>{{cite web |url=https://www.birdsinbackyards.net/species/Aythya-australis |title=Hardhead: ''Aythya australis'' |work=Birds in backyards |publisher=Birdlife Australia |access-date=9 February 2021 }}</ref>

==Gallery== <gallery widths="200px" heights="145px"> File:Aythya australis - Lake Dulverton.jpg|Standing male File:Aythya australis -Coolart Wetlands, Mornington Peninsula, Victoria, Australia -male-8.jpg|Male in flight </gallery>

== References == {{Reflist}}

== External links == {{Commons category|Aythya australis}} {{Wikispecies|Aythya australis}} * [https://datazone.birdlife.org/species/factsheet/hardhead-aythya-australis BirdLife Species Factsheet]

[[Category:Aythya]] [[Category:Birds described in 1838]] [[Category:Birds of Australia]] [[Category:Ducks]] [[Category:Taxa named by Thomas Campbell Eyton]]