Although the pallid cuckoo feeds on most insects and their larvae, including beetles, grasshoppers, butterflies and moths (2), its primary food source is hairy caterpillars (2) (3). Plant foods consumed usually include Lantana and mistletoe berries, as well as nectar (2). Insect prey is normally found on tree branches or occasionally taken while in the air (7). Pallid cuckoos may also perch on low branches, dropping to the ground to pounce on prey when it is spotted (3). To rest after feeding, the bird perches on the uppermost branches of trees or on posts or rails where it can survey the surrounding area with ease (7).
In Australia, the pallid cuckoo’s breeding season varies slightly with geographic location. For instance, in Western Australia the breeding season runs from July to January, peaking in September, whereas in the east of its range the pallid cuckoo breeds from August to January, with peaks in October and November (2).
Like other cuckoos, the pallid cuckoo is a brood parasite, meaning its eggs are laid in the nests of other birds. It typically chooses host species that are insectivorous and that build open, cup-shaped nests. Examples of suitable host species include honeyeaters, whistlers, robins and flycatchers (6). The female pallid cuckoo replaces one of the host’s eggs with her own, similar-looking egg (3), which is an elongated oval shape and is glossy and pale pink with a few small, darker pink spots. The host bird incubates and hatches this egg alongside its own over a period of 12 to 14 days (2). The cuckoo egg normally hatches first, and as early as 48 hours after hatching the cuckoo chick will instinctively eject the other eggs or young from the nest (2) (3).
The young cuckoo grows rapidly, fast exceeding the size of the host, which is kept busy searching for food to satisfy the chick’s insatiable appetite (3). Interestingly, there have been many instances of cuckoo fledglings being fed by bird species other than the host. In addition, pallid cuckoo chicks have also been known to fly to other nests, where they are fed with greater priority than the resident bird’s own young. Fledgling cuckoos are fed by the hosts for up to six weeks (2).
The pallid cuckoo is a solitary species, occurring in pairs only during courtship. In late winter and early spring, pallid cuckoos are commonly seen conspicuously perched on bare branches or fence posts (6). During the spring this species is particularly active and quarrelsome, and it is not uncommon to see two or more males noisily chasing each other between the trees. The flight of the pallid cuckoo is straight and rapid (7).