Rusty-breasted Cuckoo

The Rusty-breasted Cuckoo (Cacomantis sepulcralis) is a species of cuckoo bird belonging to the family Cuculidae. It is native to Southeast Asia and can be found in Singapore, Malaysia, Thailand, Indonesia and the Philippines. It typically inhabits forests, woodlands and mangrove swamps, preferring dense vegetation for cover.

It is a medium-sized cuckoo with a rusty-coloured breast and belly, which gives it its name. The adults have a greyish head, the upperparts are predominantly brown with darker barring, and the tail is long and graduated.

The juvenile has a different appearance compared to the adult. Its less conspicuous plumage helps it blend in with its surroundings during its early life stages. Unlike the rusty-coloured breast and belly of the adult, the juvenile cuckoo has a more uniform brown colouration on its underparts and upperparts. The overall plumage is duller and lacks the rusty tones that are prominent in the adult. As the juvenile cuckoo grows and reaches adulthood, its plumage gradually changes, and it acquires the distinctive rusty breast and belly that characterises the species.

As with most cuckoos, the Rusty-breasted Cuckoo primarily feeds on insects, including caterpillars, dragonflies, beetles, and grasshoppers. It is an insectivorous bird and will actively search for its prey in the vegetation of its habitat.

This cuckoo species is secretive and can be challenging to spot due to its elusive behaviour and excellent camouflage. It is often more easily heard than seen. During the breeding season, it is common to hear the male Rusty-breasted Cuckoo calling out with its melodious and rhythmic song. The call is a repetitive and gradually descending series of whistles described as “pee-pee-pee”, or a persistent ascending series of notes that goes like “pee-pu-pwee, pee-pu-pwee”.

As a brood parasite, the female Rusty-breasted Cuckoo typically lays its eggs in the nests of other bird species. The host bird unknowingly incubates and raises the cuckoo’s chicks, sometimes at the expense of its own offspring. This behaviour is an adaptation that allows the cuckoo to conserve energy and resources by avoiding the effort of raising its own young.

The host bird for the Rusty-breasted Cuckoo is usually the Malaysian Pied Fantail, who spares no effort to take care of its foster child. One day at Jurong Lake Gardens (Lakeside Garden), we had the opportunity to witness a delightful scene – the Malaysian Pied Fantail tirelessly tending to the newly fledged juvenile Rusty-breasted Cuckoo. The growing cuckoo has an insatiable appetite, but the fantail was relentless in its search for delectable morsels to feed the juvenile.

The breakfast menu primarily consisted of various species of dragonflies, abundant around the waters of Jurong Lake.

Occasionally, the size of the dragonfly proved a challenge and the juvenile cuckoo had to exert some effort to stuff it down its throat.

But once gulped down, the young cuckoo looked like it was hungry for more and it didn’t hesitate to bite the hand (or wing) that feeds it, as if to say “Why are you still standing there? Go get me more!!”. What an ingrate!

Once left on its own, the juvenile Rusty-breasted Cuckoo sits prettily on its perch, looking all adorable and innocent with its cute beady eyes.

The Rusty-breasted Cuckoo is a fascinating bird and we could never tire observing its interesting behaviour. Spotting this elusive cuckoo in the wild is a thrilling experience for us birdwatchers and nature enthusiasts.