eastern great egret
{{Short description|Subspecies of bird}}
{{Subspeciesbox
| image2 = Ardea modesta.jpg
| image2_caption = Non-breeding plumage in Tasmania
| image = Kotuku · Rina Sjardin-Thompson WCSW.jpg
| image_caption = Breeding plumage in New Zealand
| status =
| status_system =
| genus = Ardea
| species = alba
| species_link = Great egret
| subspecies = modesta
| authority = J.E. Gray, 1831
| synonyms = Ardea modesta
| range_map = Ardea modesta map.svg
| range_map_caption = Yellow: breeding, green: year-round, blue: non-breeding
}}
The eastern great egret (Ardea alba modesta) is a species of heron from the genus Ardea, usually considered a subspecies of the great egret (A. alba). In New Zealand it is known as the white heron or by its Māori name kōtuku. It was first described by British ornithologist John Edward Gray in 1831.
Taxonomy
This species was originally described as the "pure white heron of India", Ardea modesta, by Gray in 1831,{{Cite book|last=Gray|first=John Edward|url=https://www.biodiversitylibrary.org/bibliography/113722|title=The Zoological Miscellany|date=1831|publisher=Published by Treuttel, Wurtz and Co., G.B. Sowerby, W. Wood|location=London|doi=10.5962/bhl.title.113722}} but was later generally considered a synonym of Ardea alba, by Ellman in 1861 through to the Peters checklist in 1979.{{Cite journal |last=Ellman |first=J. B. |year=1861 |title=Brief Notes on the Birds of New Zealand |url=https://www.biodiversitylibrary.org/item/90004 |journal=The Zoologist: A Monthly Journal of Natural History |volume=19 |pages=7469}}Ardea alba modesta J.E. Gray; Payne 1979, in Peters Check-list Birds World 1 (2nd edition): 204. It was elevated to species status again by Sibley and Monroe in 1990,{{Cite book|last1=Sibley|first1=Charles G.|url=https://www.worldcat.org/oclc/23248877|title=Distribution and taxonomy of birds of the world|last2=Monroe|first2=Burt L.|date=1990|publisher=Yale University Press|isbn=0-300-04969-2|location=New Haven|oclc=23248877}} and this was supported by a 2005 revision of the herons.{{Cite book|last1=Kushlan|first1=James A.|url=https://www.worldcat.org/oclc/54913407|title=The Herons|last2=Hancock|first2=James A.|date=2005|publisher=Oxford University Press|isbn=0-19-854981-4|location=Oxford|pages=104|oclc=54913407}} It is still sometimes considered a subspecies of the great egret Ardea alba.{{Cite book|last1=Scofield|first1=R. Paul|url=https://www.wikidata.org/wiki/Q59440579|title=Checklist of the birds of New Zealand, Norfolk and Macquarie islands, and the Ross Dependency, Antarctica|last2=Medway|first2=D. G.|last3=Chambers|first3=Geoff K.|last4=Gill|first4=Brian James|last5=Bell|first5=Ben D.|last6=Palma|first6=Ricardo L.|last7=Tennyson|first7=Alan J. D.|last8=Worthy|first8=Trevor H.|publisher=Te Papa Press|year=2010|isbn=978-1-877385-59-9|location=Wellington|pages=157–158}}
Description
Measuring {{convert|83–103|cm|in|0}} in length and weighing {{convert|0.7–1.2|kg|lboz}}, the eastern great egret is a large heron with all-white plumage. Its bill is black in the breeding season and yellow at other times,[http://www.nzbirds.com/birds/kotuku.html Kōtuku, the white heron] and its long legs are red or black.{{citation needed|date=January 2016}} The colours of the bare parts of the face change to green during the breeding season. The breeding plumage is also marked by long neck plumes and a green facial area.{{cite web|date=February 12, 2010|title=Ardea modesta - Eastern Great Egret|url=http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=1004|access-date=June 11, 2010|work=Species Profile and Threats Database|publisher=Department of the Environment, Water, Heritage and the Arts, Commonwealth of Australia|location=Canberra}} The eastern great egret can be distinguished from other white egrets and herons in Asia and Australia by its very long neck, one and a half times as long as its own body.
Distribution and habitat
The eastern great egret has a wide distribution throughout Asia and Oceania, with breeding populations in Australia, Bangladesh, China, Nepal, India, Indochina, Indonesia, Japan, Korea, Myanmar, New Zealand (in the Waitangiroto Nature Reserve), Pakistan, Papua New Guinea, Philippines (Zamboanga), Russia (north-eastern), Solomon Islands, Sri Lanka, Thailand and Taiwan.{{cite web | url=https://www.heronconservation.org/herons-of-the-world/list-of-herons/eastern-great-egret/ | title=HeronConservation » Eastern Great Egret }}{{Cite web |title=Visitor impacts on freshwater avifauna in New Zealand |url=https://www.doc.govt.nz/globalassets/documents/science-and-technical/casn240.pdf}}
The egret breeds across Australia but only rarely in the southwest of the continent or dry interior.{{cite book | last = Beruldsen | first = Gordon | title = Australian Birds: Their Nests and Eggs | publisher = self | year = 2003 | location = Kenmore Hills, Qld | page = 184 | isbn = 0-646-42798-9}} The largest colonies within Australia are in the Top End and Channel Country, which can number several thousand pairs. Colonies in the southeast of Australia can number several hundred pairs. The bird is an uncommon autumn and winter visitor to Tasmania.{{cite book|last=Watts|first=Dave|title=Field Guide to Tasmanian Birds|publisher=New Holland Press|location=Frenchs Forest, NSW|year=2006|orig-year=1999|edition=2nd|page=48|isbn=1-876334-60-6}}
Behaviour
=Feeding=
=Breeding=
The eastern great egret often breeds in colonies with other herons, egrets, cormorants, spoonbills and ibises. One brood is raised a year, although the breeding season varies within Australia. In the north of the country it is in March to May, in southern and central Queensland December and January, and October to December in the south. Located atop trees at a height of {{convert|20|m|ft|0}} or more, the nest is a flat wide platform of dry branches and sticks with a shallow basin for eggs and young. The clutch consists of anywhere from two to six pale blue-green eggs, with three or four being the usual number. They are oval in shape and measure {{convert|52 x 36|mm|in|frac=8}}.
Status
The subspecies is protected in Australia under the National Parks and Wildlife Act 1974. In New Zealand the white heron is highly endangered, with only one breeding site at Waitangiroto Nature Reserve in Whataroa. In 2023, there were 56 pairs of kōtuku nesting in the reserve, an increase compared with recent years. The increase was attributed mainly to the effects of predator control around the reserve.{{Cite web |date=8 November 2023 |title=Nesting season looks promising for critically endangered kōtuku |url=https://www.rnz.co.nz/news/national/501935/nesting-season-looks-promising-for-critically-endangered-kotuku |access-date=8 November 2023 |website=RNZ |language=en-nz}} The kōtuku shares this site with the kōtuku ngutupapa, or Royal spoonbill. When Queen Elizabeth II visited New Zealand in 1953 to 1954, she was compared to the kōtuku—a compliment to rare, distinguished visitors.{{Cite news | url = https://www.nzgeo.com/stories/kotuku/ | title = Kōtuku: The story of the bird on our $2 coin | author = Andrea Graves | access-date =May 8, 2020 |work=New Zealand Geographic |issue=145 | date = May–June 2017 }} The egret is featured on the reverse side of a New Zealand $2 coin.
Images
File:Great Egrets I3- Kolkata IMG 1132.jpg|Flock at Kolkata, West Bengal, India
File:Chudaisagi 06c1467.jpg|Non-breeding plumage in Japan
File:EasternGreatEgretLongNeck.jpg|Extended neck of an egret
File:Great Egret in Flight.jpg|In flight at Lake Monger, Perth, Western Australia
File:Ardea alba modesta Phuket Thailand.jpg|Non-breeding plumage in Thailand
File:A White Heron in the Waters of the Waikanae Lagoon.jpg|At Waikanae lagoon, New Zealand
References
{{Reflist}}
External links
{{Commons category|Ardea alba modesta|Eastern great egret}}
- Seven Sharp profile of the kōtuku breeding colony, Westland, New Zealand [https://www.tvnz.co.nz/shows/seven-sharp/clips/the-kotuku-bird-returns 9 October 2023]
{{Taxonbar|from=Q1207168}}