Lesser Coucal Centropus bengalensis 小鴉鵑
Category I. Common but increasingly localised resident in grass-dominated habitats or open-canopy shrubland usually on hillsides. Much declined this century due to succession to closed-canopy habitats, a trend that is likely to continue.
IDENTIFICATION
Jun. 2005, Chun Kwok CHEUNG.
28-34 cm. Head, body and tail blackish. Scapulars, wing coverts and remiges orange-brown, the latter greyish toward the tip. Obvious pale shafts to feathers of head, chest and scapulars. Bill and legs black, eyes dark.
May 2020, John and Jemi Holmes.
Separated from Greater Coucal by smaller size, more obvious pale shafts on head, chest and upper mantle feathers, warm brown underwing coverts, browner back, often somewhat paler or duller upperparts and shorter less deeply-based bill with more rounded culmen.
Non-breeding adult is distinctive and is a plumage not shown by Greater Coucal. It comprises brown head, mantle and scapulars that have obvious pale shaft streaks, darker brown mantle, rump, uppertail coverts and tail with dull brownish barring, warm buff chest with pale shaft streaks and creamy belly and undertail coverts. Bill variably horn coloured.
VOCALISATIONS
The typical song is a series of 3-5 low-pitched and hollow ‘poop’ notes; the interval between first and second is longer than the rest, between which the interval often slightly shortens progressively. This may be followed by a short series of guttural notes.
Also, a series of approximately 15-20 ‘doop’ notes over approximately 4 seconds that progressively speed up and fall in slightly in pitch.
DISTRIBUTION & HABITAT PREFERENCE
The 2016-19 breeding atlas recorded Lesser Coucal in 12.1% of 1km squares compared to 27.6% in the 1993-96 survey. Like Chinese Francolin, which has similar habitat preferences, its range has contracted considerably, presumably for the same reasons of vegetation succession from grassland through grassland/shrubland to shrubland and forest. The decline between the two winter atlases was much less noticeable, but this species is difficult to survey when it is not vocalising.
Its decline has been fairly general across Hong Kong, but particularly noticeable on the islands of Lamma and Lantau, the lower slopes of the Tai Mo Shan massif and Sai Kung, in which areas the increase in shrubland has been very apparent. It appears to be absent from Hong Kong Island, where at the time of the first breeding atlas it was very localised, but still retains a foothold on islands such as Po Toi, Lamma and Tung Lung Chau.
Its strongholds were and remain the north and northeast New Territories, Sai Kung, Ma On Shan and Lantau, particularly the western half.
Lesser Coucal occurs mainly in grassland or shrubby grassland on hill slopes, as well as abandoned agricultural land and smaller marshy areas. It rarely occurs in the fish pond areas of Deep Bay in the non-breeding season and avoids disturbed or anthropogenic habitats.
OCCURRENCE
There is no evidence of migration or significant movements away from the breeding areas. Previous authors considered it less common than its congener Greater Coucal, and Herklots (1953) reported this species as also being highly valued in traditional Chinese medicine and frequently seen for sale in markets.
BREEDING
Herklots (1935a, b) described nests similar in structure, though smaller than those of Greater Coucal, and made of coarse grass. One was found on Cape D’Aguilar on 17 May. Adults have been observed carrying food at Tai Mo Shan on 27 June, and an unfeathered chick was found in a nest at Sha Tau Kok on 1 August.
BEHAVIOUR, FORAGING & DIET
More than its congener Greater Coucal, it vocalises from the top of bushes or dense grassy patches, although most of the time it is rather shy and less obvious. Little is known regarding prey in HK, though several large hairy caterpillars were found in the stomach of a female by Swinhoe (1861).
RANGE & SYSTEMATICS
Occurs from southwest and northeast India east through Bangladesh and Indochina to southeast China, and south through southeast Asia to the Greater and Lesser Sundas and the Philippines (Payne 2020). In China it is largely confined to areas south of the Yangtze including Hainan and Taiwan, though it extends further north in the eastern coastal region (Liu and Chen 2020).
C.b. lignator occurs in south and southeast China including HK, Hainan and Taiwan. Five other subspecies are also recognised.
CONSERVATION STATUS
IUCN: Least Concern. Population trend increasing.
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). Lesser Coucal (Centropus bengalensis), 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.lescou1.01
Swinhoe, R. 1861. Notes on the ornithology of Hong Kong, Macao and Canton, made during the latter end of February, March, April and the beginning of May 1860. Ibis 1861: 23-57.
