Horsfield's Bronze-Cuckoo Chrysococcyx basalis Scientific name definitions

17 cm; 22 g. Adult brownish bronze above , head browner than back, long white supercilium and dark eye-stripe, tail sides rufous, notched white; whitish below , throat lightly streaked, barred bronze on flanks and sides of breast, undertail barred black and white with rufous centre, underside of flight-feathers with rufous-tinged white band; wing feathers often have crisp pale margins, a feature not noted in congeners; eye-ring grey, iris brown to red, bill slender, black, feet grey. Juvenile similar but duller, plain grey-brown above, feathers sometimes buff-edged, flanks faintly barred, iris grey to light brown.

Australia and Tasmania. Winters N to Java and irregularly beyond.

Open woodland , mulga, scrub , including dry interior, spinifex, coastal saltmarsh, generally arid and semi-arid zones.

Partial migrant. A few remain all year in E Australia E of the Dividing Range and also in S of range, but more are resident in N Australia. Some birds spend non-breeding season N of Australia, and occur on passage on islands off the coast. A non-breeding visitor to S New Guinea and W through Indonesia, where generally uncommon to scarce but probably overlooked, though said to be locally common in NW Java from Mar and Apr; occasional in Sumatra and Sulawesi, recorded also in Sumbawa, Flores, Natuna Is, Borneo and Singapore.

Insects, mainly caterpillars , also beetles (Coccinellidae), bugs. Forages in foliage and on ground; flight swift and direct.

Descending high whistle  , “peeer”, repeated once every 5 sec, faster and higher than that of C. osculans.

Breeding in Western Australia varies with seasonal rains, Aug–Oct in Southwestern Division, Oct–Dec near Perth, Jan–Mar in Kimberley Division, Mar–May and Aug–Sept in Pilbara region. Brood-parasitic: hosts mainly small thornbills (Acanthiza), fairy-wrens (Malurus), and Australian robins (Petroica) and chats (Ephthianura); 28 host species known, mainly with domed nests, some with open nests. Eggs  whitish with brown flecks; 18 x 12 mm; incubation 11–13 days. Hatchling naked, skin pink and grey, darkening with age, white gape flanges, yellow mouth-lining; evicts host's eggs and chicks; fledges in 17–19 days, fed up to 4 weeks after fledging.

Not globally threatened. Common in much of breeding range, though scarce in Northern Territory and Kimberley Division of Western Australia. Reported breeding densities of 0·1 bird/ha, or 10 birds/km², are reckoned to be unusually high for this species.