Plaintive Cuckoo Cacomantis merulinus Scientific name definitions

18–23·5 cm; 19·5–32 g (1 Gaither, J. C. (1994). Weights of Bornean understorey birds. Bulletin of the British Ornithologists’ Club 114(2):89–90. Close , 2 Erritzøe, J., C. F. Mann, F. P. Brammer, and R. A. Fuller (2012). Cuckoos of the World. Christopher Helm, London, UK. Close ). Adult male nominate has pale grey head, rest of upperparts and wings dark grey and slightly glossed, some rufous on wing-coverts, rump and uppertail-coverts slate-grey, chin to upper breast grey, rest of underparts pale rufous-buff, and tail dark tipped white; eye brown to red with grey eyering, bill black sometimes with yellowish or orange mandible, and legs and feet pale yellow to yellow-olive. Female like male, but abdomen barred whitish and rectrices more barred; also occurs in rufous morph, dark rufous above  , barred with black, plain dark rufous tail (with black subterminal band), throat and breast, rest of underparts dark-barred whitish. Juvenile variable, some all dark grey, finely barred whitish on belly, others rufous with crown light rusty-brown and streaked darker brown, back and wings barred rusty and dark brown (rusty bars wider than dark brown bars), tail black with white bars and with or without rufous edge, underparts black-barred whitish. Races differ mainly in plumage: <em>querulus</em> is more strongly coloured, brown above, throat and breast grey (often washed rufous), belly rufous, and juvenile has streaked head; <em>threnodes</em> barely paler buff-rufous below than querulus, and head more contrasting with rest of upperparts; lanceolatus often paler brown above, greyish white below merging into pale rufous-buff belly and vent.

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Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Open woodland, secondary forest, lowland rainforest, freshwater and peatswamp forest, mangroves, teak and rubber, as well as Albizia plantations, kerangas, scrub, brush, gardens and cultivated areas, including in towns and villages, also grassy plains and swamps . Lowlands to c. 3000 m (in China), but typically below 2000 m in Bhutan, 1850 m in SE Asia, 1000 m in Assam, Philippines and Sumatra, and 1220 m on Borneo.

Resident and seasonally migratory. In Nepal an occasional visitor or vagrant, late Apr to Aug; in Yunnan (SW China), present Feb–Oct, and is apparently only a summer visitor through rest of Chinese range, although reportedly resident on Hainan. Presumed partly resident in NE India and Bhutan (although no records in latter country between Sept and Jan inclusive), with some local movements and wintering over much of E half of Indian subcontinent, especially NE Deccan. Many specimens from Java differ from local resident race lanceolatus, but match N race querulus, indicating immigration from N during latter’s non-breeding season.

Insects , mainly hairy  caterpillars (Saturniidae) but also hairless ones (Notodontidae), beetles, bugs, termite soldiers, other soft-bodied insects; also fruit. Appears in foliage canopy, where an active and restless forager.

Very vocal during breeding season, occasionally calling at night, but can be more or less silent at other times of year: in Greater Sundas and China, gives an ascending “pee-pipee-pee ... pipee-pee” with variations, becoming higher-pitched with each repetition, or occasionally a short “wi-pihui”; on Sulawesi, song rendered “ti-ter-wi” or “pee-to-pett”, with second note lower and last higher, again becoming higher-pitched with each repetition, and also heard to give a descending, trilled and cadenced “tee-tee-tee-tee-tita-tita-tita-tita-tee”; and in Philippines gives a gradually ascending “peet-to-peet ... peet-to-peet”, repeated four or more times.

Breeds May–Jun in Kalimantan, Mar–Sept (peak Jul) in India, May–Jul in Myanmar; fledglings Jun–late Aug, Dec–Jan in Thai-Malay Peninsula, May–Jul and Sept in Borneo, and May–Jun in Philippines. Male courtship-feeds female. Brood-parasitic: hosts mainly species that build domed nests with narrow entrance, e.g. Ashy Prinia (Prinia socialis), Hill Prinia (P. atrogularis), Grey-breasted Prinia (P. hodgsonii), Plain Prinia (P. inornata), Common Tailorbird (Orthotomus sutorius) and Zitting Cisticola (Cisticola juncidis) in Indian Subcontinent, O. sutorius in China (3 Yang, C., W. Liang, A. Antonov, Y. Cai, B. G. Stokke, F. Fossøy, A. Moksnes, and E. Røskaft (2012). Diversity of parasitic cuckoos and their hosts in China. Chinese Birds 3(1):9–32. Close ), Dark-necked Tailorbird (Orthotomus atrogularis), Grey-breasted Spiderhunter (Arachnothera modesta) and possibly Common Iora (Aegithinia tiphia) on Borneo, Yellow-bellied Prinia (Prinia flaviventris), Olive-backed Tailorbird (Orthotomus sepium), Crimson Sunbird (Aethopyga siparaja) and C. juncidis on Java. Eggs variable according to host, either plain chestnut, sometimes with darker markings at larger end, pale blue with red, dark brown and purple markings, or pinkish or bluish with red-brown markings at blunt end; mean sizes 19·1–19·8 mm × 13·3–13·8 mm. Evicts host’s eggs. No further information.

Not globally threatened. Common throughout most of range, for instance in E India, Bangladesh, Myanmar, SE China, Cambodia, Malaysia, Greater Sundas (especially Java and Bali) and C Sulawesi; very common in Thailand; fairly common in Philippines; and commonest cuckoo on Borneo. In Nepal, said to be rather scarce; nearly all observations there are of the formerly conspecific C. passerinus, with definitive sightings of race querulus being extremely rare; in contrast, the present species is commoner than C. passerinus in Bhutan. Has apparently disappeared from Singapore.