Species: White-breasted Waterhen Amaurornis phoenicurus
Other common names: White-breasted Swamphen.
Taxonomy: Amaurornis phoenicurus (Pennant) 1769, Ceylon.
Sub-species & Distribution: Six sub-species are currently recognised, extending its range from Pakistan and India east to China, Taiwan and Japan, south through Myanmar and Thailand to West Malaysia, Singapore, Borneo, Indonesia and the Philippines.
Its taxonomy is quite confusing. Three races exist on separate island groups. Of the remaining three, the smaller javanicus, and the larger chinensis are sometimes subsumed into the nominate phoenicurus by some authors due to overlapping measurements, and phoenicurus is often listed as the only form found throughout most of Asia.
Both javanicus and chinensis, though included with phoenicurus due to overlapping measurements, might be valid (Wang & Hails 2007), and it is probable that all three races occur in Singapore, javanicus being the resident form, the other two found as winter visitors and/or passage migrants:
Wing lengths of birds taken between May and September, from Singapore north to Thailand, are not above 149 mm and Malaya could be in a zone of intergradation with the smaller javanicus and, from their size, migrants are phoenicurus (Wells 1999). One bird caught at Fraser's Hill, wing = 152 mm, was attributable to chinensis (Medway & Wells 1976). Interestingly enough, of three birds from Singapore (Sreedharan 1996 & Wang 1999), all caught during the winter months, the presence of a much larger bird from Sungei Buloh (18/1/96) seems to confirm that chinensis does occur in Singapore as a seasonal migrant. The measurements of the two smaller birds from Loyang and Sungei Buloh (27/12/95) fall within the range of javanicus
Size: Size 11 to 13" (28 to 33 cm). Sexes similar.
Description: Crown, nape and back dark slaty-grey, browner on rump and washed rufous on uppertail coverts. Forehead, face and lores white, sides of throat, breast and flanks slaty-black. Wings black, wing coverts olive-grey, tail dark brown. Chin, throat, breast and belly white. Lower belly, vent, flanks and undertail coverts greyer, washed with cinnamon-red, thighs rufous-grey, underwing coverts black slaty-grey edged with white. Females are like males but slightly smaller (Robinson 1927).
Immature birds: Much duller than adults. Head and upperparts browner, flanks and undertail coverts pale rufous. Newly-hatched chicks are entirely covered with black down, with the flight feathers not formed yet, the bill black, paler at tip, tarsi and feet black.
Soft parts: Iris reddish-brown. Upper mandible greyish-yellow, orange-red at base, brighter at tip, the lower mandible yellowish-green. Tarsi, toes and soles greenish-yellow.
Status, Habitat & Behaviour: A common resident throughout Singapore, also an uncommon winter visitor and passage migrant (Wang & Hails 2007), it is easily recognised by its short tail, long yellowish legs and toes.
One of the commonest waterside birds, up to 1800 m, it is seen, singly or in small groups, wherever water is surrounded by thick vegetative cover, skulking along the edges of rivers, swamps, marshes, mangroves, reed beds, grasslands, canals, water-logged drains, padi fields, gardens and parks or open grassy verges by roadsides, even along the edges of jungle but not in dense forests. It is occasionally found beside streams in forest, in the lowlands and hills, to 1100 m in Sarawak (Wang 2004), to about 1500 m in the Cameron Highlands (Medway & Wells 1976).
Unlike other rails, it also frequents drier areas some distance away from swamps, often feeding out in the open, usually on the ground. It walk slowly and sedately, the feet lifted high off the ground, the short tail cocking up regularly, displaying its reddish undertail coverts. When disturbed, it reluctantly takes to flight, preferring, instead, to run very quickly, its tail erect, to seek shelter in tall grass just a short distance away. Less often, it rises almost vertically (Robinson 1927) with a weak fluttering flight, its yellow legs trailing behind, flying up into a nearby tree or bush where it will perch clumsily on a low branch. It often climbs about in the dense crown-foliage of waterside bushes and small trees and sometimes swims (Wells 1999), but not as much, or dive so well, as the Common Moorhen Gallinula chloropus (Robinson 1927).
The birds probe for food with their bill in mud or shallow water, sometimes in deeper water. It is often seen in padi fields. In Bario, Sarawak, the birds start feeding as early as dawn and continue until late into the evening, forming loose feeding groups with the more dominant and bigger Common Moorhen Gallinula chloropus (Wang 2004).
It is rather a quarrelsome species and fight a good deal, the birds sparring against one another in the manner of domestic chickens. They forage on the ground but clamber up into low bushes or trees to roost. They tend to be especially noisy at dawn and dusk, making loud croaky calls.
Food: It feeds on grasshoppers, worms, snails, cockroaches, insects, aquatic invertebrates, molluscs, padi and grass seeds. It is often found in rice fields, feeding on young shoots of padi and marsh plants or, more frequently, small fish (Wang 2004).
Voice and Calls: It is a very vocal and exceedingly noisy bird, especially during the breeding season, and heard in the early morning and evening. Its calls consist of a remarkable range of grunts, croaks and chuckles, more usually a loud kru-ak, kru-ak, kru-ak-a-wak-wak from which it derives its local name (Smythies 1968). It often calls long after it gets dark (Robinson 1927), even during the night.
Breeding: In Singapore, eggs have been found in January, May and July; nests in February and August; chicks during every month except April, the clutch size ranging from 2 to 5 eggs (Wang & Hails 2007), up to about 4 to 8 eggs elsewhere along its range. In Perak, nests found in February, March and May had only 3 or 4 eggs (Robinson & Chasen 1936).
The nest is a shallow cup-shaped pad made with sedges, bamboo leaves, reeds and twigs thinly covered with dry grass, placed in a dry location amidst clumps of tall reeds and grasses, or up in bushes, bamboo clumps or trees up to ten feet above the ground, always on or near water. The bird does not fly up to the nest but, instead, reaches it by climbing up the surrounding vegetation. An incident of what may have been courtship behaviour (Tan 2010) has been recorded
A nest in Malaysia was in grass only a foot high, on the edge of a buffalo wallow; another about three feet above ground in a patch of tall grass on the edge of a small stream; others being six feet above the ground, in thickets. The eggs were laid on a pad of dry grass, supported by the surrounding green and decaying vegetation (Robinson & Chasen 1936).
The eggs, about 39 9 x 30.0 mm in size and slightly glossy, are pale buff, spotted and speckled with reddish-brown, pale purple and grey, more so at the broader end. Both sexes help incubate the eggs and care for the young. The eggs take about 19 days to hatch. The newly hatched chicks, clad in black down, are very active.