Fan-tailed Cuckoo

The yellow orbital eye ring is the fan-tailed cuckoo's most reliable field mark, separating it from its close relatives. The species measures about 25–27 cm long and weighs roughly 50 grams.

Its head, back and wings are slate-grey, contrasting with rufous underparts, while the tail is barred black and white in a fan-like pattern that gives the species its name.

The yellow eye ring is especially useful for distinguishing it from the smaller, paler brush cuckoo (C. variolosus) and the also smaller chestnut-breasted cuckoo (C. castaneiventris), both of which lack this feature.

The fan-tailed cuckoo occupies a wide range across Australia, extending from Cape York in Queensland down the coast to Shark Bay in Western Australia, with a range that reaches no more than about 1,000 km inland along the west coast. In South Australia it occurs along the coast, avoiding the southeastern corner around Mount Gambier and the Eyre Peninsula, and it is also found in Tasmania. Its overall range covers roughly 2,430,000 square kilometers.

The species uses a broad mix of habitats, including temperate forests, subtropical and tropical mangrove forests, moist montane forests, and more open, human-influenced settings such as paddocks, orchards and gardens, reflecting its semi-open habitat preference.

Observation records show numbers rising through the southern spring and peaking around September, before tapering off into the southern summer, a pattern consistent with seasonal presence tied to breeding activity rather than a fixed year-round abundance.

As an insectivore, the fan-tailed cuckoo hunts by perching in an exposed spot to scan for prey, then pouncing to seize it either in the air or on the ground. Insects and their larvae make up a large part of its diet in Australia.

Beyond invertebrates, it also takes fruits and vegetables, along with small reptiles, mammals and birds, showing a particular taste for bird chicks. This mix of plant matter and small vertebrate prey alongside insects marks it as a broadly opportunistic hunter rather than a specialist.

Breeding in Australia runs from July to January, during which the fan-tailed cuckoo practices brood parasitism rather than raising its own chicks. A female lays only one egg per nesting attempt, colored mauve-white with red and brown spotting, into the nest of a host species such as a fairywren or thornbill.

The preferred host nests are domed in shape, a structure that suits the cuckoo's parasitic strategy. Once the egg is laid, the host pair incubates and rears the chick, with the adult cuckoo taking no further part in its development.

The species' voice, a descending trill paired with a grasshopper-like chirp, is heard through the breeding season, likely tied to courtship and territorial signaling around this parasitic breeding cycle.

The IUCN lists the fan-tailed cuckoo as Least Concern, a status supported by its wide range and a presumed large population. No particular threats to the species have been identified.

While the population trend is thought to be downward, the decline is not considered steep enough to warrant listing the species in a more threatened category, and it remains common across much of its range.

1. The genus name Cacomantis comes from the Greek kakos, meaning evil or ill-boding, and mantis, meaning prophet, reflecting an old association between these cuckoos' calls and predictions of rain or bad weather.
2. The subspecies Cacomantis flabelliformis flabelliformis breeds in southwestern and eastern Australia south of Cape York Peninsula, including Tasmania, and winters as far north as southern New Guinea.