Greater Coucal Centropus sinensis 褐翅鴉鵑
Category I. Widespread and common resident typically present in mangroves and shrub dominated closed and open-canopy habitats, usually in lowland areas.
IDENTIFICATION
Sep. 2020, James Kwok.
47-56 cm. Female larger than male. Large and long-tailed, often ungainly looking. Adults are plain, lacking barring on the tail, wings and upperparts. Head, body and tail black, with a blue or purple gloss, and orange-brown mantle, scapulars, wing coverts and remiges, with the latter greyish near the tip. Bill and legs are dark grey, iris red to brown. Bird illustrated is immature acquiring adult-type plumage.
Sep. 2007, CHUNG Wing Kin.
Juveniles are barred pale buff or whitish over much of body and wings; the crown, mantle, wing coverts and remiges are warm buff or warm brown, the body greyish and the tail, on which the bars are spaced more widely, is dark grey-brown. Older birds such as this retain varying amounts of barring and streaking according to progress of moult.
VOCALISATIONS
Greater Coucal is more often detected by its distinctive voice. The song, which can often be heard throughout the day from February, is a long series of deep and resonant ‘poop’ notes that descend in pitch initially before rising to the end of the strophe. It is often joined in a duet by the female, whose voice is slightly higher in pitch.
It also gives a series of hoarser and flatter ‘hoop’ notes that are higher and uniform in pitch.
Other vocalisations include a drawn out, slightly nasal, rasping ‘skeeow’ call.
DISTRIBUTION & HABITAT PREFERENCE
Widespread, occurring throughout HK. The two breeding atlases saw a small decline in the percentage of squares occupied from 31.8% to 30.4% between 1993-96 and 2016-19, while the winter atlas surveys saw an increase from 11.5% to 13.2%. It is unlikely either of these is of significance. What this species gains in increased shrubland cover it loses in succession to forest.
Densities in the breeding season appear to be highest in the northwest New Territories, the slopes of the Tai Mo Shan massif, the western half of Lantau, on Lamma Island and scattered areas of east New Territories. The recorded winter distribution was similar, and both seasons saw lowest densities in the west New Territories and urban areas, where habitat is either absent or too degraded to allow growth of the dense grass and shrub required.
Greater Coucal occurs in grassland, grass-shrub, open-canopy shrubland, mangroves (where densities appear relatively high), agricultural land, abandoned farmland with scattered trees and shrubs, fung shui woodland and gardens.
It appears to overlap with Lesser Coucal most in open-canopy shrubland.
OCCURRENCE
Greater Coucal is usually found singly or in pairs. There is no evidence of migration or significant movements away from the breeding areas, nor is there any evidence of a change in status. Previous authors considered it a very common resident in Hong Kong and the region. Herklots (1935a, 1953) reported this species was highly valued in traditional Chinese medicine and was frequently seen for sale in markets.
BREEDING
Greater Coucal builds a bulky domed nest of twigs and leaves low down in a bush and rears its own young; the earliest date on which a nest has been found is 3 February. Copulation has been observed from 29 March to 11 June, and recently-fledged birds have been recorded as early as 22 April, though are most frequently reported in August.
Reporting on five nests found between April and June, two of which contained four eggs and the others three or four young, Herklots (1935a, b, 1953) stated that they were sometimes made of sweet-potato vines woven roughly together and lined with dried sweet-potato leaves and grasses, but was more often entirely made of the leaves of Pandanus odoratissimus, which accounts for its local Cantonese name lo so tseuk , or ‘pandanus bird’. Three of the nests were placed in Pandanus stands, two in bushes. Neither sweet potato nor Pandanus is grown in significant quantities in HK today. A nest at Mai Po in the 1980s was found in a mangrove Avicennia marina approximately 300 metres from dry land.
BEHAVIOUR, FORAGING & DIET
A skulking species that generally avoids being in the open, except sometimes when vocalising, sunning itself or drying feathers after rain. It clambers awkwardly through vegetation or run-flies on its long legs into cover if disturbed on the ground; it rarely flies long distances and prefers to climb to the top of a tree or bush from where it flaps and glides to its destination.
Moves stealthily through vegetation or hops and runs when chasing prey items; it is regularly seen foraging at muddy margins of fish ponds. Food items recorded in Hong Kong include grasshoppers (Vaughan and Jones 1913), human excrement (Herklots 1935a), snails, frogs, lizards, vegetable matter and fruit (Herklots 1953), the young or eggs of birds and snakes, including a White-lipped Pit Viper Tremeresurus albolabris approximately 60cm long.
RANGE & SYSTEMATICS
Resident from the Indian subcontinent east to southeast China and south through southeast Asia to the Greater Sundas (Payne 2020). In China it occurs in much of the area south of the Yangtze, including Hainan, but is absent from Taiwan (Liu and Chen 2020).
Nominate C.s. sinensis occurs from Pakistan through north India to southeast China including HK. Five other subspecies are recognised.
CONSERVATION STATUS
IUCN: Least Concern. Population trend stable.
Herklots, G.A.C. 1935a. The birds of Hong Kong. Part XVIII. Family Cuculidae (Cuckoos), Sub-family Phoenicophainae (Ground-Cuckoos). Hong Kong Naturalist 6: 1-4.
Herklots, G.A.C. 1935b. Crow-pheasants, additional notes. Hong Kong Naturalist 6: 87-88.
Herklots, G.A.C. 1953. Hong Kong Birds. South China Morning Post, Hong Kong.
Liu, Y. and Y. H. Chen (2020). The CNG Field Guide to the Birds of China (in Chinese). Hunan Science and Technology Publication House, Changsha.
Payne, R. B. (2020). Greater Coucal (Centropus sinensis), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.grecou1.01
Vaughan, R.E. and Jones, K.H. 1913. The birds of Hong Kong, Macao and the West River or Si Kiang in South-East China, with special reference to their nidification and seasonal movements. Ibis 1913: 17-76, 163-201, 351-384.
