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Sep 25 2011

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Slaty Egret (Egretta vinaceigula)

Slaty Egret

[order] CICONIIFORMES | [family] Ardeidae | [latin] Egretta vinaceigula | [authority] Sharpe, 1895 | [UK] Slaty Egret | [FR] Aigrette vineuse | [DE] Braunkehl-Reiher | [ES] Garceta gorgirroja | [NL] Sharpe’s Reiger

Subspecies

Genus Species subspecies Region Range
Egretta vinaceigula AF sc

Genus

Egretta is a genus of medium-sized herons, mostly breeding in warmer climates. Representatives of this family 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 to colonise the Americas. Little Egret Egretta garzetta in Kolleru, Andhra Pradesh, India.These are typical egrets in shape, long-necked and long-legged. There are few plumage features in common, although several have plumes in breeding plumage; a number of species are either white in all plumages, have a white morph (e.g. Reddish Egret), or have a white juvenile plumage (Little Blue Heron). The breeding habitat of Egretta herons is marshy wetlands in warm countries. They nest in colonies, often with other wading birds, usually on platforms of sticks in trees or shrubs.

Physical charateristics

Small, dark egret. Adult appears blue-grey, sometimes pale blue-grey, but may appear black in poor light. White throat and dark reddish foreneck only visible at close range. Legs and toes greenish-yellow with variable amount of chrome yellow around joints in breeding adults. Juvenile is paler and rufous on throat extends from throat down neck.


wingspan min.: 0 cm wingspan max.: 0 cm
size min.: 43 cm size max.: 60 cm
incubation min.: 22 days incubation max.: 25 days
fledging min.: 0 days fledging max.: 0 days
broods: 1   eggs min.: 1  
      eggs max.: 4  

Range

Africa : Southcentral. Occurs in Zambia (perhaps 500-1,000 birds, notably at Liuwa Plain, Kafue Flats and Bangweulu in some years, although breeding not recorded), northern Botswana (probably over 2,000 birds, mostly around the Okavango Delta and Chobe river, where breeding occurs in at least 10 heronries), and northern Namibia (c.300 birds, especially along the Chobe floodplain and Caprivi Strip). It wanders more widely when not breeding, and occurs more sparsely in Democratic Republic of Congo, Zimbabwe, and occasionally South Africa.

Habitat

It inhabits river floodplains, marshes, and temporary shallow wetlands, preferring areas where water levels are receding from their seasonal peak. It tends to avoid open water, being most often found in areas where there is ample cover of short, emergent vegetation. It forages in water less than 10cm in depth. Breeding It breeds in temporary wetlands at the time of – or shortly after – maximum water levels. Its preferred breeding habitat is Phragmites reedbed13, but it will also nest on islands of vegetation.

Reproduction

The nest is a bowl lined with fine plant material, usually on a platform constructed from sticks, and the species shows high nest-site fidelity. Clutch-size has been recorded as 1-4 eggs and the incubation period in one nest was recorded as 22-24 days.

Feeding habits

When possible it feeds mainly on young fish, especially cichlids, but in temporary wetlands where fish do not occur, its diet consists of frogs, aquatic invertebrates and tadpoles. It locates prey by sight in clear, shallow water. Additionally it will glean snails from lily pads and uses ‘standing flycatching’ to catch dragonflies and other insects. It is thought to feed almost exclusively on fish except. It forages diurnally, often in association with other heron and wader species.

Video Slaty Egret

httpv://www.youtube.com/watch?v=g6TofOGVvwE

copyright: madmurd


Conservation

This species is classified as Vulnerable because it has a small and declining population. Apparently suitable habitat is widely available throughout its range, yet it is never common, thus its rarity remains unexplained.
The wetlands inhabited by this species face many threats, including: flood regulation, water abstraction, land-claim for agriculture11, reed-cutting (through disturbance and burning), fire, rice production and disturbance from tourists. It is known to have disappeared from part of the Kafue Flats due to flood control by humans, which involved damming the Kafue River. At the Okavango Delta (Botswana) food availability appears to be limited and any decrease would impact the survival of adult and immature birds. The aerial spraying of Deltamethrin to eradicate tsetse flies could potentially reduce food availability, as the pesticide is known to affect small fish and aquatic invertebrates. The presence of Salvinia molesta in some areas reduces visibility by covering the water surface and probably affects foraging by the species.
Slaty Egret status Vulnerable

Migration

This species is mostly sedentary. It shows some movements in response to rains, which cause seasonal variation in habitat conditions. However the movements are in general poorly understood. It occurs year-round in some areas (such as Zambia) where it is not known to breed.

Distribution map

Slaty Egret distribution range map

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Permanent link to this article: http://www.planetofbirds.com/ciconiiformes-ardeidae-slaty-egret-egretta-vinaceigula

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