The Pacific reef heron (''Egretta sacra''), also known as the eastern reef heron or eastern reef egret, is a species of
heron found throughout southern
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
and
Oceania
Oceania (, , ) is a geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern and Western hemispheres, Oceania is estimated to have a land area of and a population of around 44.5 million ...
. It occurs in two colour morphs with either slaty grey or pure white plumage. The sexes are similar in appearance.
Taxonomy
The Pacific reef heron was
formally described in 1789 by the German naturalist
Johann Friedrich Gmelin in his revised and expanded edition of
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...
's ''
Systema Naturae''. He placed it with the herons, cranes and egrets in the
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
''
Ardea'' and coined the
binomial name ''Ardea sacra''. Gmelin based his description on the "Sacred heron" that had been described in 1785 by the English ornithologist
John Latham in his multi-volume work ''A General Synopsis of Birds''. The naturalist
Joseph Banks had provided Latham with a specimen of a white morph that had been collected on Tahiti. The Pacific reef heron is now placed with 12 other species in the genus ''
Egretta
''Egretta'' is a genus of medium-sized herons, mostly breeding in warmer climates.
Representatives of this genus are found in most of the world, and the little egret, as well as being widespread throughout much of the Old World, has now started ...
'' that was introduced in 1817 by the German naturalist
Johann Reinhold Forster
Johann Reinhold Forster (22 October 1729 – 9 December 1798) was a German Reformed (Calvinist) pastor and naturalist of partially Scottish descent who made contributions to the early ornithology of Europe and North America. He is best known ...
.
The genus name comes from the
Provençal French for the
little egret, ''aigrette'', a diminutive of ''aigron'', "heron". The specific epithet ''sacra'' is from
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''sacer'' meaning "sacred". The Pacific reef heron is referred to by a variety of names by the indigenous peoples of the Pacific region. In
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
, multiple names have been given, including ''kākatai'', ''matuku moana'' and ''matuku tai''. It is known as ''belō'' in Fiji, ''matu'u'' in the
Samoan Islands
The Samoan Islands ( sm, Motu o Sāmoa) are an archipelago covering in the central South Pacific, forming part of Polynesia and of the wider region of Oceania. Administratively, the archipelago comprises all of the Independent State of Samoa an ...
, and ''motuku'' in
Niue
Niue (, ; niu, Niuē) is an island country in the South Pacific Ocean, northeast of New Zealand. Niue's land area is about and its population, predominantly Polynesian, was about 1,600 in 2016. Niue is located in a triangle between Tong ...
,
Tonga
Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in ...
, and
Wallis Island
Wallis ( Wallisian: ''Uvea'') is a Polynesian atoll/island in the Pacific Ocean belonging to the French overseas collectivity (''collectivité d'outre-mer'', or ''COM'') of Wallis and Futuna. It lies north of Tonga, northeast of Fiji, east-n ...
.
Two
subspecies are recognised:
[
* ''E. s. sacra'' (Gmelin, JF, 1789) – coastal south Bangladesh and Andaman Islands to ]Ryukyu Islands
The , also known as the or the , are a chain of Japanese islands that stretch southwest from Kyushu to Taiwan: the Ōsumi, Tokara, Amami, Okinawa, and Sakishima Islands (further divided into the Miyako and Yaeyama Islands), with Yona ...
(south Japan), Australasia (except south outlying islands), Melanesia (except New Caledonia) to Tuamotu Archipelago
The Tuamotu Archipelago or the Tuamotu Islands (french: Îles Tuamotu, officially ) are a French Polynesian chain of just under 80 islands and atolls in the southern Pacific Ocean. They constitute the largest chain of atolls in the world, extendin ...
(east Polynesia)
* ''E. s. albolineata'' ( Gray, GR, 1859) – New Caledonia including Loyalty Islands
The Loyalty Islands Province (French ''Province des îles Loyauté'') is one of three administrative subdivisions of New Caledonia encompassing the Loyalty Island (french: Îles Loyauté) archipelago in the Pacific, which are located northeast of ...
Description
Pacific reef herons are medium-sized herons, reaching 57 to 66 cm in length. They have a wingspan of between 90 and 110 cm and reach an average weight of 400 grams. The species displays an unusual, non-sexual dimorphism, with some members having entirely white plumage ('light' morph) and others (the larger portion) being charcoal-grey ('dark' morph). The reason for the colour variation or " morph", is unknown, though it is most commonly thought to be related to camouflage. The plumage of immature herons tends to be browner and duller in colour.
Pacific reef herons have yellow-grey legs, and the grey variety's throats and chins are marked by a narrow, white stripe. They have brown beaks, gold-yellow coloured eyes and the surrounding areas of their faces are normally of a greenish to yellow cast.
Distribution and habitat
The Pacific reef heron is widely distributed across southern Asia and Oceania. In Australia, Pacific reef herons inhabits most of the coastline, and offshore islands including the Torres Strait Islands
The Torres Strait Islands are a group of at least 274 small islands in the Torres Strait, a waterway separating far northern continental Australia's Cape York Peninsula and the island of New Guinea. They span an area of , but their total land ...
.
Pacific reef herons are widespread across Micronesia
Micronesia (, ) is a subregion of Oceania, consisting of about 2,000 small islands in the western Pacific Ocean. It has a close shared cultural history with three other island regions: the Philippines to the west, Polynesia to the east, and ...
, with breeding records in Guam
Guam (; ch, Guåhan ) is an organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. It is the westernmost point and territory of the United States (reckoned from the geographic cent ...
, the Marshall Islands
The Marshall Islands ( mh, Ṃajeḷ), officially the Republic of the Marshall Islands ( mh, Aolepān Aorōkin Ṃajeḷ),'' () is an independent island country and microstate near the Equator in the Pacific Ocean, slightly west of the Intern ...
, Northern Mariana Islands
The Northern Mariana Islands, officially the Commonwealth of the Northern Mariana Islands (CNMI; ch, Sankattan Siha Na Islas Mariånas; cal, Commonwealth Téél Falúw kka Efáng llól Marianas), is an unincorporated territory and commonw ...
, and Palau
Palau,, officially the Republic of Palau and historically ''Belau'', ''Palaos'' or ''Pelew'', is an island country and microstate in the western Pacific. The nation has approximately 340 islands and connects the western chain of the ...
, among various other islands. The species also breeds throughout western Polynesia
Polynesia () "many" and νῆσος () "island"), to, Polinisia; mi, Porinihia; haw, Polenekia; fj, Polinisia; sm, Polenisia; rar, Porinetia; ty, Pōrīnetia; tvl, Polenisia; tkl, Polenihia (, ) is a subregion of Oceania, made up of ...
, including in Fiji, French Polynesia, and Tonga
Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in ...
– though it does not breed in Niue
Niue (, ; niu, Niuē) is an island country in the South Pacific Ocean, northeast of New Zealand. Niue's land area is about and its population, predominantly Polynesian, was about 1,600 in 2016. Niue is located in a triangle between Tong ...
. Surveys of the Fijian island of Rotuma
Rotuma is a Fijian dependency, consisting of Rotuma Island and nearby islets. The island group is home to a large and unique Polynesian indigenous ethnic group which constitutes a recognisable minority within the population of Fiji, known as " ...
, conducted in 1991 and 2018, suggest that the Pacific reef heron has recently colonized the island.
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
is considered to be the southern limit of the Pacific reef heron's distribution. Despite being relatively uncommon, the herons are found throughout the country, though are most common in Northland.
Behaviour and ecology
Breeding
The species lay clutches of eggs year-round in colonies in the jungle, between palms and mangroves or in cavities of old buildings. Two to three paled greenish-blue eggs are laid in nests constructed from branches and blossoms. Males and females share brooding tasks. They normally have a 28-day brood period. After chicks are hatched, parents provide approximately five weeks of support.[
]
Food and feeding
Their food sources are made up predominantly of varieties of ocean-based fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...
, crustaceans
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gro ...
, molluscs
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estim ...
and worms.
Conservation status
In New Zealand, the Pacific reef heron has the conservation status of "Nationally endangered". It has been classified as "Regionally Critical" in the Wellington region
Greater Wellington, also known as the Wellington Region (Māori: ''Te Upoko o te Ika''), is a non-unitary region of New Zealand that occupies the southernmost part of the North Island. The region covers an area of , and has a population of
T ...
.
Gallery
Eastern Reef Egret - dark morph.jpg, Dark morph
Eastern reef egrets in Ko Tao.jpg, Two colour morphs, Ko Tao, Thailand
Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...
Eastern Reef-Egret96.ogg, Mooloolaba
Mooloolaba is a coastal suburb of Maroochydore in the Sunshine Coast Region, Queensland, Australia. It is located north of the state capital, Brisbane, and is part of the Maroochydore urban centre. In the , Mooloolaba had a population of 7,73 ...
, Australia
Juvenile Reef Egret.jpg, Juvenile dark morph, Coral Bay, Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
References
{{Taxonbar, from=Q392232
Egretta
Birds of Southeast Asia
Birds of the Pacific Ocean
Pacific reef heron
The Pacific reef heron (''Egretta sacra''), also known as the eastern reef heron or eastern reef egret, is a species of heron found throughout southern Asia and Oceania. It occurs in two colour morphs with either slaty grey or pure white pluma ...
Pacific reef heron
The Pacific reef heron (''Egretta sacra''), also known as the eastern reef heron or eastern reef egret, is a species of heron found throughout southern Asia and Oceania. It occurs in two colour morphs with either slaty grey or pure white pluma ...
Articles containing video clips