Milky Stork (Mycteria cinerea)

Milky Stork

[order] CICONIIFORMES | [family] Ciconiidae | [latin] Mycteria cinerea | [authority] Raffles, 1822 | [UK] Milky Stork | [FR] Tantale blanc | [DE] Milchstorch | [ES] Tantalo Malayo | [NL] Maleise Nimmerzat

Subspecies

Genus Species subspecies Region Range
Mycteria cinerea OR s Vietnam, Sumatra, Java, Sulawesi

Genus

Mycteria is a genus of large tropical storks with representatives in the Americas, east Africa and southern and southeastern Asia. Two species have “ibis” in their scientific or old common names, but they are not related to these birds and simply look more similar to an ibis than do other storks. The Mycteria storks are large birds, typically around 90?100 cm in length with a 150 cm wingspan. The body plumage is mainly white in all the species, with black in the flight feathers of the wings. The Old World species have a bright yellow bill, red or yellow bare facial skin and red legs, but these parts are much duller in the Wood Stork of tropical America. Juvenile birds are a duller version of the adult, generally browner, and with a paler bill. They are broad-winged soaring birds that fly with the neck outstretched and legs extended. They are resident breeders in lowland wetlands with trees in which build large stick nests.
Two prehistoric relatives of the Wood Stork have been described from fossils. 1) Mycteria milleri (Miller’s Stork) (Valentine Middle Miocene of Cherry County, USA) – formerly Dissourodes. 2) Mycteria wetmorei (Wetmore’s Stork) (Late Pleistocene of W and SE USA, and Cuba)
The latter seems to have been a larger sister species of the Wood Stork, which it replaced in prehistoric North America. Late Miocene tarsometatarsus fragments (Ituzaingo Formation at Parana, Argentina) are somewhat similar to Mycteria but still distinct enough to be probably a distinct genus, especially considering their age. A Late Pleistocene distal radius from San Josecito Cavern (Mexico) may belong in this genus or in Ciconia. A “ciconiiform” fossil fragment from the Touro Passo Formation found at Arroio Touro Passo (Rio Grande do Sul, Brazil) might be of the living species M. americana; it is at most of Late Pleistocene age, a few 10.000s of years.

Physical charateristics

White stork with thick, yellowish bill and blackish flight feathers. Juvenile has paler brown, more streaked head and neck, and darker wing-coverts contrasting sharply with upperparts. Similar spp. Painted Stork M. leucocephalus has black markings on wing-coverts and breast, pink on inner wing-coverts and tertials and more restricted naked head skin.


wingspan min.: 0 cm wingspan max.: 0 cm
size min.: 92 cm size max.: 97 cm
incubation min.: 27 days incubation max.: 30 days
fledging min.: 43 days fledging max.: 50 days
broods: 1   eggs min.: 1  
      eggs max.: 4  

Range

Oriental Region : South Vietnam, Sumatra, Java, Sulawesi. Mycteria cinerea occurs in Cambodia, Peninsular Malaysia and the islands of Sumatra, Java, Bali, Sumbawa, Sulawesi and Buton, Indonesia. Its population is estimated at less than 5,500 individuals. The majority are in Indonesia, with less than 5,000 on Sumatra and c.400 in west Java. There are estimated to be c.10-20 pairs at Tonle Sap lake, Cambodia. It is a vagrant to Thailand and Vietnam. Numbers have apparently declined, at least in parts of its range, with counts from Malaysia falling consistently from over 100 individuals in 1984, to less than 10 birds in 2005. Its status in Indonesia has received less study, but although good numbers can still be found at some sites in southern Sumatra there are reports that numbers have declined considerably

Habitat

It is a predominantly coastal resident in Indonesia and Malaysia, inhabiting mangroves and adjacent, less saline, swamps. It forages on tidal mudflats, in saline pools, freshwater marshes, fishponds and rice-fields. Birds only occur inland in flooded forest around Tonle Sap lake in Cambodia, from where they disperse in the wet season.

Reproduction

There appears to be marked differences and seasonality in breeding throughout the range of the species. At Tonle Sap, Cambodia, egg-laying apparently takes place during the dry season in January and February, while in Malaysia two nests contained three eggs on 18 August and the Kuala Gula colony was noted as ?active? in November. In Indonesia, breeding occurs during the ?dry season? and usually lasts until October. Clutches taken on Java date from
March, May and July, a Javan colony mostly contained fledged and almost full-grown young (with one clutch unhatched) in July. In Sumatra a bird was seen in breeding plumage in May and egg-laying occurs in June-August. Nest structure and sites: Breeding is colonial, often occurring in multi-species aggregations. In Sumatra the species has been recorded nesting alongside Lesser Adjutant, Black-headed Ibis and several species of heron. Although breeding has never been authenticated at Tonle Sap, Cambodia, local reports suggest that the species nests in colonies containing Painted Stork, Lesser Adjutant and Spot-billed Pelicans during the dry season (January and February).
Breeding colonies in Indonesia vary considerably in structure – with reports of some birds
nesting close to the ground in dense stands of mangrove fern, others in
mature mangroves or dead and dying mangrove trees between 8 and 30m off the ground, with
some colonies close to the sea and others far inland. The major breeding colonies in Sumatra
were mostly in mangrove back swamps; at Tanjung Koyan the colony was some 2 km from the
coast, in dense beds of Acrostichum spp. fern, with nests built 3-4 m high in bushes around a small pool; at Tanjung Selokan, about 1-2 km from the coast, nests were 5-15 m high in 10-12 dead trees within a 15 ha flooded area; on the Banyuasin peninsula, between 3-4 km inland, nests were 2-6 m high in small bushes around a pool in dense Acrostichum spp. fern beds; and at Kuala Betara, the colony was situated in the outer mangrove fringe between 8 to 12 high in Avicennia sp., and Rhizophora apiculata mangrove trees. Two other nesting colonies were also reported further inland. On Java a colony of 75-100 nests was reported in large Avicennia marina trees covering an area of 4.5 ha, with each tree generally holding 5-7 nests, sometimes 10, rarely only 2-3. In the Citarum Delta only very tall trees were used, one of these containing 22 nests.
In Malaysia, a colony of 20 nests was between 8 and 10 m high in both living and dead
mangrove trees, mostly the latter; in another case two nests were placed in the tops of mangrove trees. Nests are fairly bulky structures of sticks, lined with fresh leafy twigs, in general resembling the nests of Grey Heron but containing thicker branches. Twigs and fresh leaves for the nest are sometimes collected from some distance away. Clutch size, incubation and fledging: Nine clutches from Java consisted of three eggs, although nests in one large colony held mostly two young, one with one and a few with three, and clutches of four eggs have been recorded. In 1984, nests at Pulau Rambut, Java, mostly contained two young. Two nests in Malaysia both contained three young (Robinson and Chasen
1936). The incubation period is estimated at 27-30 days; by 6-7 weeks the young are able to
leave the nest and fly poorly, and by eight weeks they fly well but are still fed in the nest by parents (Hoogerwerf 1936b). Small young are fed more frequently than large young; before they are four weeks old chicks may be fed twice per hour, whereas older nestlings may only be fed once per afternoon. When temperatures are high, adults sometimes bring
water to the nest and drool it from their bills to cool the nestlings or allow them to drink.

Feeding habits

At Sungai Burong, Malaysia, the bulk of the diet appeared to be large mudskippers Periophthalmus spp. of 10-23 cm in length. In Indonesia the species has also been reported consuming snakes and frogs, and fish. It has been reported that nestlings are fed on eels and mudskippers up to 20 cm in length. Milky Storks often feed in aggregations with other wading birds, such as Lesser Adjutant and egrets, and the species generally employs a tactile foraging technique, involving standing still or walking through mud and usually shallow water, probing with a partly opened bill, or drawing it in an arc from side to side, until a prey item is located by touch; it has also been observed seeking food by foot-stirring. Less frequently, individuals either detect prey by sight or root them from their burrows. On locating a mudskipper hole an individual will probe its bill in the immediate vicinity 10-15 times, sometimes immersing the whole bill and head into the mud and then hauling out the prey once it has been secured in the bill. Birds have been observed feeding in loose flocks between 50 and 100 m apart, but sometimes they will move in a single
tight flock, flushing fish in shallow water. At Pulau Dua, Indonesia, considerable nocturnal activity was noted, with birds both foraging and visiting nests during hours of darkness, at least under a full moon

Video Milky Stork

httpv://www.youtube.com/watch?v=QPr67R7D9nA

copyright: Anthony Laven


Conservation

This stork qualifies as Vulnerable because it has undergone a rapid population decline owing to ongoing loss of coastal habitat, human disturbance, hunting and trade. However, further data are needed onrates of decline in Sumatra, its stronghold.
The population is estimated at 5,000 individuals in Sumatra in the late 1980s, others estimated 100-150 individuals in Java. The total in Indonesia is now likely to be <5,000 individuals. Population in Malaysia estimated to be 10 in 2005. Overall population therefore likely to total c.5,000 individuals or fewer
Milky Stork status Vulnerable

Migration

No Milky Stork population undertakes a regular long distance migration, although birds in Cambodia (and possibly Thailand and Vietnam) appear to make seasonal movements in relation to wet and dry periods. Although Malay Peninsula and Sumatran birds seem to be essentially resident there may be some movement across the Malacca Straits. Movements have also between observed across the Sunda Straits (between Sumatra and Java) and further east in Sumbawa and Bali suggesting some regular, small-scale dispersal does take place.

Distribution map

Milky Stork distribution range map

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