Mesophoyx intermedia

Taxonomy

Assessment Information

Geographic Range

Habitat and Ecology

Threats

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	CICONIIFORMES	ARDEIDAE

Scientific Name:

Mesophoyx intermedia

Species Authority:

(Wagler, 1829)

Common Name/s:

English	–	Intermediate Egret, Yellow-billed Egret
French	–	Aigrette intermédiaire

Assessment Information [top]

Red List Category & Criteria:

Least Concern ver 3.1

Year Assessed:

2009

Assessor/s:

BirdLife International

Reviewer/s:

Bird, J., Butchart, S.

Justification:
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

History:

2008	–	Least Concern
2004	–	Least Concern

Geographic Range [top]

Countries:	Native: Angola; Australia; Bangladesh; Benin; Bhutan; Botswana; Brunei Darussalam; Burkina Faso; Burundi; Cambodia; Cameroon; Cape Verde; Central African Republic; Chad; China; Congo; Congo, The Democratic Republic of the; Côte d'Ivoire; Eritrea; Ethiopia; Gabon; Gambia; Ghana; Guam; Guinea; Guinea-Bissau; India; Indonesia; Japan; Kenya; Korea, Democratic People's Republic of; Korea, Republic of; Lao People's Democratic Republic; Lesotho; Liberia; Malawi; Malaysia; Mali; Mauritania; Mozambique; Myanmar; Namibia; Nepal; Niger; Nigeria; Northern Mariana Islands; Oman; Pakistan; Palau; Papua New Guinea; Philippines; Russian Federation; Rwanda; Senegal; Sierra Leone; Singapore; Somalia; South Africa; Sri Lanka; Sudan; Swaziland; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Timor-Leste; Uganda; Viet Nam; Zambia; Zimbabwe Vagrant: Christmas Island; Jordan; Maldives; New Zealand; Seychelles; United Arab Emirates; United States; Yemen
Range Map:	Click here to open the map viewer and explore range.

Countries:

Native:

Angola; Australia; Bangladesh; Benin; Bhutan; Botswana; Brunei Darussalam; Burkina Faso; Burundi; Cambodia; Cameroon; Cape Verde; Central African Republic; Chad; China; Congo; Congo, The Democratic Republic of the; Côte d'Ivoire; Eritrea; Ethiopia; Gabon; Gambia; Ghana; Guam; Guinea; Guinea-Bissau; India; Indonesia; Japan; Kenya; Korea, Democratic People's Republic of; Korea, Republic of; Lao People's Democratic Republic; Lesotho; Liberia; Malawi; Malaysia; Mali; Mauritania; Mozambique; Myanmar; Namibia; Nepal; Niger; Nigeria; Northern Mariana Islands; Oman; Pakistan; Palau; Papua New Guinea; Philippines; Russian Federation; Rwanda; Senegal; Sierra Leone; Singapore; Somalia; South Africa; Sri Lanka; Sudan; Swaziland; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Timor-Leste; Uganda; Viet Nam; Zambia; Zimbabwe

Vagrant:

Christmas Island; Jordan; Maldives; New Zealand; Seychelles; United Arab Emirates; United States; Yemen

Range Map:

Click here to open the map viewer and explore range.

Habitat and Ecology [top]

Habitat and Ecology:	Behaviour North-Asian populations of this species are fully migratory, leaving Japan in September-October to winter in the Philippines and Borneo⁴, and returning to breeding colonies in April¹. The majority is predominantly sedentary however, with some populations making limited nomadic or partially migratory movements² in response to changing water levels³. The breeding season varies regionally¹, but is usually centered around the wet season⁴, with birds breeding in mixed-species colonies¹ of between 7, 20³ and hundreds of pairs (sometimes up to thousands)⁵. The species is diurnal^{1, 4} and usually feeds singly, but old records suggest⁴ that it may form flocks of 15-20 individuals (sometimes up to 250)^{1, 2}, occasionally forming concentrations around permanent water during droughts⁴. During the night the species roosts communally in trees over water^{1, 3} in groups of 20 or more⁵. Habitat The species inhabits lowlands from sea-level to 1,000 m in Sumatra, and 1,450 m in Nepal¹. It shows a preference for sheltered flood-plains and seasonal wetlands with water less than 80 mm deep and emergent grasses, herbs, sedges, reeds or rushes and abundant aquatic vegetation⁵ (generally avoiding areas where vegetation is too thick for feeding)⁴. Such habitats include seasonally flooded marshes, inland deltas (e.g. Okavango Basin, Botswana)³, ponds, swamp forest⁴, freshwater swamps, pools, rivers, streams, rice-fields, the margins of freshwater, brackish and saltwater lakes^{1, 2, 4}, wet meadows, and flooded and dry pasture near water^{1, 2, 3, 4}. It occurs less often in coastal habitats, but may roost in mangrove swamps^{1, 7}, and frequents mudflats, tidal estuaries¹, coastal lagoons², saltmarshes, and tidal streams and rivers^{4, 5}. Diet In aquatic habitats the diet of this species consists predominantly of fish less than 10 cm long^{1, 3} (including eels, perch Macquaria, gudgeon and mosquitofish Gambusia)⁴, as well as frogs, crustaceans (e.g. crayfish)^{1, 3, 4} and aquatic insects (e.g. leeches, water bugs and dragonfly larvae)^{1, 3, 4}. It will also take terrestrial prey in drier habitats⁴ including grasshoppers^{1, 3}, mole crickets, bugs and beetles, snakes⁴, spiders^{,1, 3, 4} lizards^{1, 4}, and exceptionally birds¹. Breeding site The species breeds colonially with other species¹ but does not concentrate into dense groups; individual nests being typically situated 0.5 m away from each other⁵. The nest is a shallow platform of sticks and other marshland vegetation^{2, 3, 4} usually positioned in trees standing in water or over reedbeds^{2, 5} (e.g. in inland swamps or mangroves)⁴, at heights of 3-6 m and occasionally up to 20 m¹. The species may also nest on ledges, in reedbeds or in bushes².
Systems:	Terrestrial; Freshwater; Marine

Habitat and Ecology:

Behaviour North-Asian populations of this species are fully migratory, leaving Japan in September-October to winter in the Philippines and Borneo⁴, and returning to breeding colonies in April¹. The majority is predominantly sedentary however, with some populations making limited nomadic or partially migratory movements² in response to changing water levels³. The breeding season varies regionally¹, but is usually centered around the wet season⁴, with birds breeding in mixed-species colonies¹ of between 7, 20³ and hundreds of pairs (sometimes up to thousands)⁵. The species is diurnal^{1, 4} and usually feeds singly, but old records suggest⁴ that it may form flocks of 15-20 individuals (sometimes up to 250)^{1, 2}, occasionally forming concentrations around permanent water during droughts⁴. During the night the species roosts communally in trees over water^{1, 3} in groups of 20 or more⁵. Habitat The species inhabits lowlands from sea-level to 1,000 m in Sumatra, and 1,450 m in Nepal¹. It shows a preference for sheltered flood-plains and seasonal wetlands with water less than 80 mm deep and emergent grasses, herbs, sedges, reeds or rushes and abundant aquatic vegetation⁵ (generally avoiding areas where vegetation is too thick for feeding)⁴. Such habitats include seasonally flooded marshes, inland deltas (e.g. Okavango Basin, Botswana)³, ponds, swamp forest⁴, freshwater swamps, pools, rivers, streams, rice-fields, the margins of freshwater, brackish and saltwater lakes^{1, 2, 4}, wet meadows, and flooded and dry pasture near water^{1, 2, 3, 4}. It occurs less often in coastal habitats, but may roost in mangrove swamps^{1, 7}, and frequents mudflats, tidal estuaries¹, coastal lagoons², saltmarshes, and tidal streams and rivers^{4, 5}. Diet In aquatic habitats the diet of this species consists predominantly of fish less than 10 cm long^{1, 3} (including eels, perch Macquaria, gudgeon and mosquitofish Gambusia)⁴, as well as frogs, crustaceans (e.g. crayfish)^{1, 3, 4} and aquatic insects (e.g. leeches, water bugs and dragonfly larvae)^{1, 3, 4}. It will also take terrestrial prey in drier habitats⁴ including grasshoppers^{1, 3}, mole crickets, bugs and beetles, snakes⁴, spiders^{,1, 3, 4} lizards^{1, 4}, and exceptionally birds¹. Breeding site The species breeds colonially with other species¹ but does not concentrate into dense groups; individual nests being typically situated 0.5 m away from each other⁵. The nest is a shallow platform of sticks and other marshland vegetation^{2, 3, 4} usually positioned in trees standing in water or over reedbeds^{2, 5} (e.g. in inland swamps or mangroves)⁴, at heights of 3-6 m and occasionally up to 20 m¹. The species may also nest on ledges, in reedbeds or in bushes².

Systems:

Terrestrial; Freshwater; Marine

Threats [top]

Major Threat(s):	This species has declined markedly in Japan since the 1960s due to pollution and the disturbance of nesting colonies^{1, 7}. The species is also threatened in the Northern Territory of Australia by the degradation of flood-plain habitats owing to grazing, burning, invasion by introduced plants⁵ (particularly Mimosa pigra and Salvinia molesta⁶), reduced water flows from drainage and water diversion for irrigation^{5, 8}, levee breaking by feral buffalo^{5, 6} (allowing salt intrusion and accumulation of tidal sediment⁵), clearing of swamp forest, and pollution from mineral extraction⁶. Utilisation This species is hunted and traded at traditional medicine markets in Nigeria⁹.

Major Threat(s):

This species has declined markedly in Japan since the 1960s due to pollution and the disturbance of nesting colonies^{1, 7}. The species is also threatened in the Northern Territory of Australia by the degradation of flood-plain habitats owing to grazing, burning, invasion by introduced plants⁵ (particularly Mimosa pigra and Salvinia molesta⁶), reduced water flows from drainage and water diversion for irrigation^{5, 8}, levee breaking by feral buffalo^{5, 6} (allowing salt intrusion and accumulation of tidal sediment⁵), clearing of swamp forest, and pollution from mineral extraction⁶. Utilisation This species is hunted and traded at traditional medicine markets in Nigeria⁹.

Citation:	BirdLife International 2009. Mesophoyx intermedia. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 08 February 2012.
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