Western reef heron

Last updated

Western reef heron
Western reef egret (Egretta gularis schistacea) dark morph.jpg
E. g. schistacea dark morph

Dohat Arad Lagoon, Muharraq, Bahrain

Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Pelecaniformes
Family: Ardeidae
Genus: Egretta
Species:
E. gularis
Binomial name
Egretta gularis
(Bosc, 1792)
Egretta gularis map.svg
Range with subspecies and related species. For dimorpha, see dimorphic egret

The western reef heron (Egretta gularis), also called the western reef egret, is a medium-sized heron found in southern Europe, Africa and parts of Asia. It has a mainly coastal distribution and occurs in several plumage forms: a slaty-grey plumage in which it can only be confused with the rather uncommon dark morph of the Little egret (Egretta garzetta); a white form which can look very similar to the little egret although the bill tends to be paler and larger and the black form with white throat E. g. gularis of West Africa. There are also differences in size, structure and foraging behaviour. There have been suggestions that the species hybridizes with the Little Egret, and based on this, some authors treat schistacea and gularis as subspecies of Egretta garzetta. Works that consider the Western Reef Heron as a valid species include the nominate gularis and schistacea as subspecies.

Contents

Description

This bird has two plumage colour forms. There is an all-white morph and a dark grey morph; morphs can also occur with intermediate shades of grey which may be related to age [2] or particoloured in grey and white. The white morph is similar in general appearance to the little egret, but has a larger yellower bill, extended yellow on thicker legs, and when foraging tends to be very active, sometimes also moving its wing or using it to shade the water surface. The grey morph has a whitish throat and is unlikely to be confused with any other species within the range of this egret with beak and legs similar to that of the white morph. During the breeding season the legs and facial skin are reddish. [3] Breeding birds have two long feathers on the sides of the nape. The nominate subspecies gularis has a range from West Africa to Gabon, with some birds breeding in southern Europe. Subspecies schistacea (Hemprich & Ehrenberg, 1828) breeds from the Persian Gulf along the coast of India to the east of the India Peninsula. The bill of gularis is more pointed while schistacea has the larger bill especially towards the base. The form on the eastern coast of South Africa is usually separated as the dimorphic egret Egretta dimorpha. [4] [5] [6] The dark and white morph is thought to be controlled by a single allele with the dark character being incompletely dominant over the gene for white. [7]

Taxonomy and systematics

The species was first described as Ardea gularis from a specimen obtained in Senegal by the French naturalist Louis Augustin Guillaume Bosc in 1792. The distinctive white throat (or gular region) in the dark morph gives it the species name. Later authors have treated it the genera Demiegretta (in which dimorphic egrets were once included [8] ), Herodias and Lepterodius until its current stable position in the genus Egretta. The distinctness of this species from Egretta garzetta has however been highly debated with some authors treating garzetta as a polytypic superspecies. There has been confusion related to what were thought to be dark little egrets and the possibility of hybrids. Dark morphs in little egrets are extremely rare and nearly all specimens of what were thought to be dark morphs have turned out to be western reef herons. [9] In India some research claimed circumstantial evidence of interbreeding with little egrets, but the same researchers noted that the breeding seasons of the two species were different. [10] Hybridization has also been claimed to occur in Morocco [11] and Kenya (but this might refer to Egretta dimorpha). [12] Christidis and Boles quote a report by McCracken and Sheldon (2002) that the nucleotide sequences of the cytochrome b genes from a sampled little egret and a western reef heron were identical and use this as evidence for demotion. The sequences and the origins of the samples are not publicly available or verifiable. [13] In the past the Indian form which was also described as Ardea asha by William Henry Sykes has been treated as a subspecies of the little egret as Egretta garzetta schistacea on the basis of presumed hybridization with Egretta gularis. The lores of breeding little egrets are blue while those of the reef heron are reddish although some individuals of schistacea show blue and this is thought to be due to hybridization. [3] The dark coastal form of Madagascar, Aldabra, Comoro Islands, Seychelles and parts of East Africa (southern Kenya to Tanzania) was earlier treated as a subspecies (the mainland African form has sometimes been considered as schistacea) but is now raised to full species as the dimorphic egret (Egretta dimorpha). [4] [14] [15]

Distribution and status

It occurs mainly on the coasts in tropical west Africa, the Red Sea, the Persian Gulf (Iran) [17] extending east to India. It also occurs in the Lakshadweep Islands and Sri Lanka where breeding was once recorded at Chilaw. [18] The nominate subspecies breeds in west Africa from Mauritania to Gabon. Birds may also be found off the mainland such as in the Canary Islands. Small numbers breed in Spain. [19] Subspecies schistacea is found from the Red Sea coast east round the Indian coast. [4] Breeding colonies are known from the east coast of India around Pulicat Lake. [20] They occasionally occur further inland. [21]

The western reef heron (nominate subspecies) occurs as a vagrant in North America, South America and the Caribbean islands. [22] [23] [24] [25] [26] [27] [28] Based on the growing number of records it is suspected that they may establish breeding colonies in Brazil. [29] Several records around 1980–90 in Germany, Austria and France have been attributed to birds that escaped from an animal dealer in Mittelfranken. [9]

Behaviour and ecology

These birds stalk their prey in shallow water, often running or stirring the water with their feet or flicking their wings to disturb prey; they may also stand still and wait to ambush prey. They eat fish, crustaceans, and molluscs. In coastal areas, they regularly feed on mudskippers. [18] Laboratory studies show them to be capable of making corrections for refractions but the probability of missing increases when they are forced to strike at prey at very acute angles to the water surface. [30] Like other herons and egrets they have few vocalizations, making a low kwok or grating sounds when disturbed or near the nest. [18]

The western reef heron's breeding habitat is coastal wetlands. In the Red Sea region the breeding season is from June to August. The nominate subspecies breeds in West Africa from late April to September. In India the breeding season is during the monsoon rains from April to August and end of May in the former breeding colony at Chilaw in Sri Lanka. Most of the breeding colonies in Gujarat in western India were on mangroves. [31] They nest in colonies usually of their own species but sometimes with other egrets and smaller herons, usually on platforms of sticks placed in trees or shrubs. The male fetches sticks of the nest while the female places them to form the platform. The nest height varies from about 5 to 15 meters, but very low nesting (as low as 0.6 meters) has been observed in mangrove trees in salt pans. The usual clutch is three to four eggs which are light blue as in the little egret. Incubation begins when the first egg is laid resulting in chicks with size disparities. Both parents take turns to incubate and the eggs hatch after about 23 to 24 days. The chicks are white with grey dapples. Young birds sometimes die after falling off from the nest platform. Adults will shade the chicks during the hotter parts of the day. Predators of eggs include rats and young chicks may be taken by cats and crows. Adults usually guard the nest when eggs or young chicks are present. Adults feed the young by regurgitating semi-digested food at the nest. This diet includes mainly small fishes of the families Clupeidae, Gobiidae and Engraulidae. [32] The young birds leave the nest after about a month. [18] [33] [34]

Related Research Articles

<span class="mw-page-title-main">Egret</span> Type of bird of the heron family

Egrets are herons, generally long-legged wading birds, that have white or buff plumage, developing fine plumes during the breeding season. Egrets are not a biologically distinct group from herons and have the same build.

<span class="mw-page-title-main">Heron</span> Family of birds

Herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera Botaurus and Ixobrychus are referred to as bitterns, and, together with the zigzag heron, or zigzag bittern, in the monotypic genus Zebrilus, form a monophyletic group within the Ardeidae. Egrets do not form a biologically distinct group from herons, and tend to be named differently because they are mainly white or have decorative plumes in breeding plumage. Herons, by evolutionary adaptation, have long beaks.

<span class="mw-page-title-main">Great egret</span> Species of bird

The great egret (Ardea alba), also known as the common egret, large egret, or great white egret or great white heron is a large, widely distributed egret. The four subspecies are found in Asia, Africa, the Americas, and southern Europe. Recently it is also spreading to more northern areas of Europe. Distributed across most of the tropical and warmer temperate regions of the world, it builds tree nests in colonies close to water.

<span class="mw-page-title-main">Little egret</span> Species of water bird

The little egret is a species of small heron in the family Ardeidae. It is a white bird with a slender black beak, long black legs and, in the western race, yellow feet. As an aquatic bird, it feeds in shallow water and on land, consuming a variety of small creatures. It breeds colonially, often with other species of water birds, making a platform nest of sticks in a tree, bush or reed bed. A clutch of three to five bluish-green eggs is laid and incubated by both parents for about three weeks. The young fledge at about six weeks of age.

<span class="mw-page-title-main">Indian pond heron</span> Species of heron

The Indian pond heron or paddybird is a small heron. It is of Old World origins, breeding in southern Iran and east to the Indian subcontinent, Burma, and Sri Lanka. They are widespread and common but can be easily missed when they stalk prey at the edge of small water-bodies or even when they roost close to human habitations.

<span class="mw-page-title-main">Shikra</span> Species of bird

The shikra is a small bird of prey in the family Accipitridae found widely distributed in Asia and Africa where it is also called the little banded goshawk. The African forms may represent a separate species but have usually been considered as subspecies of the shikra. The shikra is very similar in appearance to other sparrowhawk species including the Chinese goshawk and Eurasian sparrowhawk. They have a sharp two note call and have the typical flap and glide flight. Their calls are imitated by drongos and the common hawk-cuckoo resembles it in plumage.

<span class="mw-page-title-main">Common tailorbird</span> Species of bird

The common tailorbird is a songbird found across tropical Asia. Popular for its nest made of leaves "sewn" together and immortalized by Rudyard Kipling as Darzee in his Jungle Book, it is a common resident in urban gardens. Although shy birds that are usually hidden within vegetation, their loud calls are familiar and give away their presence. They are distinctive in having a long upright tail, greenish upper body plumage and rust coloured forehead and crown. This passerine bird is typically found in open farmland, scrub, forest edges and gardens. Tailorbirds get their name from the way their nest is constructed. The edges of a large leaf are pierced and sewn together with plant fibre or spider silk to make a cradle in which the actual nest is built. Punjab tailor birds produce shiny red eggs, but became extinct around 1975 due to laying their eggs in fields used to grow fodder crops.

<span class="mw-page-title-main">Intermediate egret</span> Species of bird

The intermediate egret, median egret, smaller egret or medium egret is a medium-sized heron. Some taxonomists put the species in the genus Egretta or Mesophoyx. It is a resident breeder in southern and eastern Asia.

<span class="mw-page-title-main">Purple sunbird</span> Species of bird

The purple sunbird is a small bird in the sunbird family found mainly in South and Southeast Asia but extending west into parts of the Arabian peninsula. Like other sunbirds they feed mainly on nectar, although they will also take insects, especially when feeding young. They have a fast and direct flight and can take nectar by hovering like a hummingbird but often perch at the base of flowers. The males can appear all black in harsh sunlight but the purple iridescence is visible on closer observation or under good light conditions. Females are olive above and yellowish below.

<span class="mw-page-title-main">Red-vented bulbul</span> Species of bird

The red-vented bulbul is a member of the bulbul family of passerines. It is a resident breeder across the Indian subcontinent, including Sri Lanka extending east to Burma and parts of Bhutan and Nepal. It has been introduced in many other parts of the world and has established itself in New Zealand, Argentina, Tonga and Fiji, as well as parts of Samoa, Australia, USA and Cook Islands. It is included in the list of the world's 100 worst invasive alien species.

<span class="mw-page-title-main">Jungle babbler</span> Species of bird

The jungle babbler is a member of the family Leiothrichidae found in the Indian subcontinent. Jungle babblers are gregarious birds that forage in small groups of six to ten birds, a habit that has given them the popular name of "Seven Sisters" in urban Northern India, and in Bengali, with cognates in other regional languages which also mean "seven brothers".

<span class="mw-page-title-main">Yellow-billed babbler</span> Species of brown-grey bird from southern India and Sri Lanka

The yellow-billed babbler is a member of the family Leiothrichidae endemic to southern India and Sri Lanka. The yellow-billed babbler is a common resident breeding bird in Sri Lanka and southern India. Its habitat is scrub, cultivation and garden land. This species, like most babblers, is not migratory, and has short rounded wings and a weak flight and is usually seen calling and foraging in groups. It is often mistaken for the jungle babbler, whose range overlaps in parts of southern India, although it has a distinctive call and tends to be found in more vegetated habitats. Its name is also confused with Turdoides leucocephala, which is also known as white-headed babbler.

<span class="mw-page-title-main">Indian robin</span> Species of bird

The Indian robin is a species of passarine bird in the family Muscicapidae. It is widespread in the Indian subcontinent and ranges across Bangladesh, Bhutan, India, Nepal, Pakistan and Sri Lanka. The males of the northern subspecies have brown backs whose extent gradually reduces southwards, with the males of the southern subspecies having all-black backs. They are commonly found in open scrub areas and often seen running along the ground or perching on low thorny shrubs and rocks. The long tail is usually held up and the chestnut undertail coverts and dark body make them easily distinguishable from pied bushchats and Oriental magpie-robins.

<span class="mw-page-title-main">Thick-billed flowerpecker</span> Species of bird

The thick-billed flowerpecker is a tiny bird in the flowerpecker group. They feed predominantly on fruits and are active birds that are mainly seen in the tops of trees in forests. It is a resident bird with a wide distribution across tropical southern Asia from India east to Indonesia and Timor with several populations recognized as subspecies some of which are sometimes treated as full species.

<span class="mw-page-title-main">Pacific reef heron</span> Species of bird

The Pacific reef heron, 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 plumage. The sexes are similar in appearance.

<span class="mw-page-title-main">Baya weaver</span> Species of bird found in southeast Asia

The baya weaver is a weaverbird found across the Indian Subcontinent and Southeast Asia. Flocks of these birds are found in grasslands, cultivated areas, scrub and secondary growth and they are best known for their hanging retort shaped nests woven from leaves. These nest colonies are usually found on thorny trees or palm fronds and the nests are often built near water or hanging over water where predators cannot reach easily. They are widespread and common within their range but are prone to local, seasonal movements mainly in response to rain and food availability.

<span class="mw-page-title-main">Fauna of the Cocos (Keeling) Islands</span>

The terrestrial fauna of the Cocos (Keeling) Islands is unsurprisingly depauperate, because of the small land area of the islands, their lack of diverse habitats, and their isolation from large land-masses. However, the fauna dependent on marine resources is much richer.

<span class="mw-page-title-main">K. K. Neelakantan</span> Indian ornithologists

K. K. Neelakantan better known by his pen name Induchoodan, was a leading Indian ornithologist. He is widely regarded as a pioneer of the environmental movement in Kerala for popularizing bird study through his books written in Malayalam.

<span class="mw-page-title-main">Dimorphic egret</span> Species of bird

The dimorphic egret is a species of heron in the family Ardeidae. It is found in Comoros, Kenya, Madagascar, Mayotte, Seychelles, and Tanzania.

<span class="mw-page-title-main">Wayanad laughingthrush</span> Species of bird

The Wayanad laughingthrush is a species of laughingthrush in the family Leiothrichidae. It is endemic to the Western Ghats south of Goa in India. These laughingthrushes move in groups in dense forests, producing loud calls but tend to be hard to spot in the undergrowth. They have brown upperparts, a white throat, a broad black mask through the eye and a heavy bill with pale yellow on the lower mandible. Despite the name, derived from the Wayanad region, this species has a wider range than the four other south Indian species of laughingthrush that are restricted to the higher elevation hills.

References

  1. ↑ BirdLife International (2016). "Egretta gularis". IUCN Red List of Threatened Species . 2016: e.T22729692A95020328. doi: 10.2305/IUCN.UK.2016-3.RLTS.T22729692A95020328.en . Retrieved 11 November 2021.
  2. ↑ Dharmakumarsinhji, K.S. (1984). "Some notes on the Indian Reef Heron". J. Bombay Nat. Hist. Soc. 81 (1): 188–189.
  3. 1 2 Parasharya, B.M.; Naik, R.M. (1987). "Changes in the soft part coloration of the Indian Reef Heron, Egretta gularis (Bosc) related to age and breeding status". J. Bombay Nat. Hist. Soc. 84 (1): 1–6.
  4. 1 2 3 Dubois, Philippe J.; Yésou, Pierre (1995). "Identification of western reef egrets and dark Little Egrets". British Birds. 88: 307–319.
  5. ↑ Rasmussen, P.C.; Anderton, J.C. (2005). Birds of South Asia. The Ripley Guide. Volume 2. Washington DC and Barcelona: Smithsonian Institution and Lynx Edicions. p. 55.
  6. ↑ Parasharya, B.M.; Naik, R.M. (1984). "The juvenile plumage of the Little Egret compared with that of the White-phase Indian Reef Heron". J. Bombay Nat. Hist. Soc. 81 (3): 693–695.
  7. ↑ Naik, R.M.; Parasharya, B.M. (1983). "Sequence of plumage changes and polymorphism in the Indian Reef Heron, Egretta gularis". Sandgrouse. 5: 75–81.
  8. ↑ Berlioz, J. (1956). "The dimorphic egrets". J. Bombay Nat. Hist. Soc. 54 (1): 188–190.
  9. 1 2 Magyar, G.; Yésou, P. (2000). "Reconsideration of a Hungarian specimen of a black-coloured egret as Western Reef Egret (Egretta gularis)" (PDF). Aquila. 105–106: 35–40.
  10. ↑ Naik, R.M.; Parasharya, B.M.; Patel, B.H.; Mansuri, A.P. (1981). "The timing of breeding season and interbreeding between the colour phases in the Indian Reef Heron Egretta gularis (Bosc)". J. Bombay Nat. Hist. Soc. 78 (3): 494–497.
  11. ↑ Qninba, A.; Benhoussa, A.; Ibn Tattou, M.; El Idrissi Essougrati, A.; Haj, S. Ben; Idrissi, H. Rguibi (2011). "Cas probable d'hybridation Aigrette garzette Egretta garzetta x Aigrette des récifs Egretta gularis dans l'archipel d'Essaouira (Maroc)" (PDF). Alauda (in French). 79: 241–242.
  12. ↑ Hancock, J; Naik, RM (1986). Inter-breeding between the Little Egret and the Western Reef Heron in India, Africa and possibly Israel. Abstract No. 411. 19th International Ornithological Congress.
  13. ↑ Christidis, Les; Boles, Walter E. (2008). Systematics and taxonomy of Australian birds . CSIRO. p.  110.
  14. ↑ Grant, CHG & Mackworth-Praed, CW (1938). "A further note on the Relationship, Status, and Distribution of Egretta garzetta, E. gularis, E. schistacea and E. dimorpha". Bulletin of the British Ornithologists' Club. 59 (417): 24–26.
  15. ↑ Grant, CHB & C. W. Mackworth-Praed (1933). "On the Relationship, Status and Range of Egretta garzetta, Demiegretta gularis, D. schistacea, D. asha, and D. dimorpha, a new subspecies and the correct type-locality of Egretta garzetta". Bulletin of the British Ornithologists' Club. 53: 189–196.
  16. ↑ Koparde, Pankaj; Yesou, Pierre (2017). "Probable hybrids Little Egret x Indian Reef Heron in India and Sri Lanka" (PDF). Dutch Birding. 39: 238–246.
  17. ↑ Etezadifar, Farzaneh; Amini, Hamid (2010). "Current Status of the Breeding Population of the Western Reef Heron Egretta gularis along the Northern Coasts of the Persian Gulf and Oman Sea, and its Wintering Population in the South of Iran" (PDF). Podoces. 5 (2): 71–80.
  18. 1 2 3 4 Ali, Salim; Ripley, S. Dillon (1978). Handbook of the birds of India and Pakistan. Volume 2 (2nd ed.). New Delhi: Oxford University Press. pp. 75–76.
  19. ↑ Dies, J.I.; Prosper, J.; Dies, B. (2001). "Occasional breeding by Western Reef Egret in eastern Spain" (PDF). British Birds. 94: 382–386.
  20. ↑ Kirkpatrick, K.M. (1961). "The Ashy Reef Heron, Egretta gularis (Bosc) on the East Coast". J. Bombay Nat. Hist. Soc. 58 (1): 275.
  21. ↑ Neavoll, George F. (1968). "Occurrence of the Reef Heron [Egretta gularis (Bosc.)] in Hyderabad District". J. Bombay Nat. Hist. Soc. 65 (1): 215–216.
  22. ↑ Paice, Michael R. (2006). "First record of the Western Reef-heron (Egretta gularis) for St. Vincent and the Grenadines" (PDF). Journal of Caribbean Ornithology. 19 (1): 46–48.
  23. ↑ Murphy, W. L.; Nanan, W. (1987). "First confirmed record of Western Reef-Heron (Egretta gularis) for South America". American Birds. 41: 16–27.
  24. ↑ Davis Jr., William E. (1985). "Foraging Behavior of a Western Reef Heron in North America". Colonial Waterbirds. 8 (1): 70–73. doi:10.2307/1521198. JSTOR   1521198.
  25. ↑ Kenefick, Martyn; Hayes, Floyd E. (2006). "Trans-Atlantic vagrancy of Palearctic birds in Trindidad and Tobago" (PDF). J. Carib. Ornithol. 19: 61–72.
  26. ↑ Wilson, A. (2007). "Western Reef-Heron (Egretta gularis gularis) at Calvert Vaux Park, Brooklyn". Kingbird. 57 (4): 288–294.
  27. ↑ Cardillo, R.; Forbes-Watson, A.; Ridgely, R. (1983). "The Western Reef–Heron (Egretta gularis) at Nantucket Island, Massachusetts". American Birds. 37 (5): 827–829.
  28. ↑ Murphy, William L. (1992). "Notes on the Occurrence of the little egret (Egretta garzetta) in the Americas, with Reference to Other Palearctic Vagrants". Colonial Waterbirds. 15 (1): 113–123. doi:10.2307/1521360. JSTOR   1521360.
  29. ↑ Fedrizzi, Carmem E.; Carlos, Caio J.; Vaske Jr., Teodoro; Bugoni, Leandro; Viana, Danielle; Véras, Dráusio P. "Western Reef-Heron Egretta gularis in Brazil (Ciconiiformes: Ardeidae)" (PDF). Revista Brasileira de Ornitologia. 15 (3): 481–483.
  30. ↑ Katzir, Gadi; Lotem, Arnon; Intrator, Nathan (1989). "Stationary underwater prey missed by reef herons, Egretta gularis: head position and light refraction at the moment of strike" (PDF). Journal of Comparative Physiology A. 165 (4): 573–576. doi:10.1007/BF00611243. S2CID   6191096.
  31. ↑ Naik, R.M.; Parasharya, B.M. (1987). "Impact of the food availability, nesting-habitat destruction and cultural variations of human settlements on the nesting distribution of a coastal bird, Egretta gularis, in Western India". J. Bombay Nat. Hist. Soc. 84 (2): 350–360.
  32. ↑ Etezadifar, Farzaneh; Barati, Ahmad (2011). "Nestling diet of the Western Reef Heron, Egretta gularis, in Hara Biosphere Reserve, Persian Gulf". Zoology in the Middle East. 54 (1): 131–133. doi:10.1080/09397140.2011.10648885. S2CID   83867378.
  33. ↑ Tere, Anika (2004). "Nesting of Western Reef-Egret Egretta gularis in the saltpans of G.H.C.L., Dholera". Newsletter for Ornithologists. 1 (5): 73–74.
  34. ↑ Parasharya, B.M.; Naik, R.M. (1988). "Breeding biology of the Indian Reef heron". J. Bombay Nat. Hist. Soc. 85 (2): 251–262.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.