Horsfield's bronze-cuckoo (Chrysococcyx basalis)

Horsfield's bronze-cuckoo fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
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Horsfield's bronze-cuckoo description

A very small cuckoo ⁽²⁾, Horsfield’s bronze-cuckoo (Chrysococcyx basalis) is only around the size of a sparrow, but it has the long tail and long, pointed wings typical of cuckoo species ⁽⁴⁾. The male and female Horsfield’s bronze-cuckoo are similar in appearance, with olive-brown upperparts and a bronze-green sheen on the back and wings. Pale edges to some of the feathers give the wings and upperparts a scaled appearance ^{(2) (3) (5)}.

Horsfield’s bronze-cuckoo can also be recognised by the conspicuous dark stripe through its eye, which is bordered above by a contrasting white stripe ^{(2) (3)}. The throat is white with fine dark markings, while the underside of the body is whitish and there are black bars on the flanks ^{(2) (3) (5)}. The tail of Horsfield’s bronze-cuckoo is glossy olive-brown above and grey below, with reddish-brown at the base and black and white spots on the tip and sides ^{(2) (3)}. The undersides of this species’ wings are dark grey and marked with a broad white stripe ⁽²⁾.

Although very similar in appearance, the male and female Horsfield’s bronze-cuckoo can usually be separated by the colour of their eyes, which are typically red to dark brown in males and paler brown in females. Both sexes have a blackish beak and dark grey feet ⁽²⁾. Juvenile Horsfield’s bronze-cuckoos are duller and paler than the adults, lack barring on the underparts and have only a very faint white line above the eye ^{(2) (3)}.

Outside of the breeding season, Horsfield’s bronze-cuckoo is generally a quiet and unobtrusive bird. However, during the breeding season the male calls from an exposed perch, both by day and by night. Its call is a plaintive, descending whistle, described as ‘whe-o’ or ‘tseeeuw’, which is repeated many times. Horsfield’s bronze-cuckoo also gives a high-pitched chirruping and sometimes a chattering ‘cheer-r-r-r’ ^{(2) (6)}.

Also known as

Australian bronze-cuckoo, Horsfield’s bronze cuckoo, Horsfield’s cuckoo, narrow-billed bronze cuckoo, narrow-billed bronze-cuckoo, rufous-tailed bronze cuckoo, rufous-tailed bronze-cuckoo.

Synonyms

Chalcites basalis, Cuculus basalis, Cuculus neglectus, Lamprococcyx modesta.

Size

Length: 16 - 18 cm ^{(2) (3)}

Male weight: 17 - 30 g ⁽²⁾

Female weight: 20 - 32 g ⁽²⁾

Horsfield's bronze-cuckoo biology

The diet of Horsfield’s bronze-cuckoo consists mainly of insects and their larvae, particularly hairy caterpillars. However, this species also sometimes eats plant matter, such as berries. Horsfield’s bronze-cuckoo forages both in the trees and on the ground, and will also snatch insects from the air or take caterpillars hanging on sticky threads ^{(2) (3)}.

Horsfield’s bronze-cuckoo may breed in almost any month in northern parts of its range ^{(2) (3)}, but breeding usually takes place between July and February in the south ⁽³⁾. Like many other cuckoos, Horsfield’s bronze-cuckoo is a brood parasite which lays its eggs in the nests of other bird species. Horsfield’s bronze-cuckoo usually parasitises birds that build dome nests, particularly fairy-wrens (Maluridae species) and thornbills (Acanthiza species). However, it also sometimes uses the open cup nests of other species ^{(2) (3) (6)}.

The female Horsfield’s bronze-cuckoo lays a single egg into each host nest ^{(3) (8)}, generally laying in the early morning and visiting the nest for only a matter of seconds. At the same time, the female removes one of the host bird’s eggs, taking it away in her beak ^{(2) (4) (8)}. The Horsfield’s bronze-cuckoo egg closely mimics those of this species’ main hosts ^{(2) (4) (8)}, but if it is laid before those of the host bird, it may be built over or abandoned ⁽³⁾. Each female Horsfield’s bronze-cuckoo may lay up to 14 eggs each season, although around 6 eggs is more usual ⁽⁹⁾.

Horsfield’s bronze-cuckoo eggs hatch after about 12 days, and just a day or so after hatching the chick pushes the eggs and chicks of the host bird out of the nest. To complete its deception, the young cuckoo imitates the begging calls of the young of its host, and the host birds feed it as if it was their own chick ^{(2) (3)}. The cuckoo chick leaves the nest at around 15 to 19 days old ⁽²⁾, and the adult birds continue to feed it for several more weeks ^{(2) (3)}. Intriguingly, the superb fairy-wren (Malurus cyaneus) is able to detect and abandon Horsfield’s bronze-cuckoo chicks, as the adults call to their unhatched young and on hatching the chicks develop begging calls that match those of the adults. The cuckoo chick, however, is unable to learn these calls ⁽²⁾.

Adult Horsfield’s bronze-cuckoos are usually solitary ^{(2) (6)}, and females occupy distinct breeding ranges that encompass the territories of a number of host birds ⁽⁹⁾. Pairs of Horsfield’s bronze-cuckoos have been found to be monogamous for as long as the female continues breeding ⁽⁹⁾.

Horsfield's bronze-cuckoo range

Horsfield’s bronze-cuckoo breeds across Australia, including Tasmania, with more southerly populations moving to New Guinea, Indonesia, the Malaysian Peninsula and the Lesser Sunda Islands during the winter months ^{(2) (3) (5) (7)}.

Horsfield's bronze-cuckoo habitat

Horsfield’s bronze-cuckoo is found in a range of woodland and forest habitats, including woodlands with a grass, shrub or heath understorey, and sometimes coastal salt marshes. It also occurs in wooded farmland, orchards, gardens and towns, and has been recorded in remnant patches of forest ^{(2) (3) (6)}.

Horsfield's bronze-cuckoo status

Horsfield’s bronze-cuckoo is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Horsfield's bronze-cuckoo threats

Horsfield’s bronze-cuckoo is a widespread species and is abundant over most of its range ⁽⁷⁾. Its populations are generally thought to be stable ⁽⁷⁾, but declines have occurred in parts of Western Australia where its host birds have been affected by land clearance for agriculture ^{(2) (3) (10)}. This land clearance has resulted in habitat fragmentation, which appears to negatively affect Horsfield’s bronze-cuckoo as it requires large patches of suitable habitat with a sufficient number of host pairs ⁽¹⁰⁾.

Horsfield's bronze-cuckoo conservation

Horsfield’s bronze-cuckoo is listed on the Environment Protection and Biodiversity Conservation Act 1999, which provides a framework for the protection of Australia’s wildlife and natural environment ⁽¹¹⁾. No other specific conservation measures are currently known to be in place for this small cuckoo species.

Find out more

Find out more about Horsfield’s bronze-cuckoo and its conservation:

• BirdLife International - Horsfield’s bronze-cuckoo:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=1228
• The Internet Bird Collection - Horsfield’s bronze-cuckoo:
  http://ibc.lynxeds.com/species/horsfields-bronze-cuckoo-chrysococcyx-basalis
• Birds in Backyards - Horsfield’s bronze-cuckoo:
  http://www.birdsinbackyards.net/species/Chalcites-basalis

More information on conservation in Australia:

• BirdLife Australia:
  http://www.birdlife.org.au/
• Australian Conservation Foundation:
  http://www.acfonline.org.au/
• Australian Wildlife Conservancy:
  http://www.australianwildlife.org/

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Glossary

Brood parasite

An animal that lays its eggs in the nests of members of its own or other species; the host then raises the young as its own.

Larvae

Stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.

Monogamous

Having only one mate during a breeding season, or throughout the breeding life of a pair.

Territory

An area occupied and defended by an animal, a pair of animals or a colony.

References

1. IUCN Red List (March, 2013)
   http://www.iucnredlist.org/
2. Erritzøe, J., Mann, C.F., Brammer, F.P. and Fuller, R.A. (2012) Cuckoos of the World. Christopher Helm, London.
3. Birds in Backyards - Horsfield’s bronze-cuckoo:
   http://www.birdsinbackyards.net/species/Chalcites-basalis
4. Davies, N.B. (2000) Cuckoos, Cowbirds and Other Cheats. T & AD Poyser, London.
5. Jeyarajasingam, A. (2012) A Field Guide to the Birds of Peninsular Malaysia and Singapore. Second Edition. Oxford University Press, Oxford.
6. Tzaros, C. (2005) Wildlife of the Box-Ironbark Country. CSIRO Publishing, Collingwood, Australia.
7. BirdLife International - Horsfield’s bronze-cuckoo (March, 2013)
   http://www.birdlife.org/datazone/speciesfactsheet.php?id=1228
8. Brooker, M.G. and Brooker, L.C. (1989) The comparative breeding behaviour of two sympatric cuckoos, Horsfield’s bronze-cuckoo Chrysococcyx basalis and the shining bronze-cuckoo Chrysococcyx lucidus, in Western Australia: a new model for the evolution of egg morphology and host specificity in avian brood parasites. Ibis, 131(4): 528-547.
9. Langmore, N.E., Adcock, G.J. and Kilner, R.M. (2007) The spatial organization and mating system of Horsfield’s bronze-cuckoos, Chalcites basalis. Animal Behaviour, 74: 403-412.
10. Brooker, M. and Brooker, L. (2003) Brood parasitism by Horsfield’s bronze-cuckoo in a fragmented agricultural landscape in Western Australia. Emu, 103: 357-361.
11. Department of Sustainability, Environment, Water, Population and Communities (2013) Chrysococcyx basalis. In: Species Profile and Threats Database. Department of Sustainability, Environment, Water, Population and Communities, Canberra. Available at:
    http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=82672