By Annie Hill
The original article in Russell Lights | Ngā Mārama o Kororāreka, November 2025 edition
There are only two migratory land birds in Aotearoa New Zealand, and both are cuckoos. There’s a story that early Ma ori noticed cuckoos flying south every spring and returning in autumn, which may have led them to suspect that there could be other islands. Polynesian navigators famously studied migratory flight patterns and used them as an aid for finding their way around the ocean. They would have certainly noticed the seasonal absence of certain birds and probably observed which way they were headed.
The Pī pī wharauroa Shining Cuckoo (chalcites lucidus lucidus) is endemic to Aotearoa and usually arrives around late September. I’m sure everyone has heard its call – a loud ‘kui-kui-kui-kui . . . peooo’, even if they didn’t realise it was a cuckoo. Once you’ve recognised it, it’s unmistakeable (you can find recordings at nzbirdsonline.org.nz), and for me, hearing pī pī wharauroa means spring has arrived. If you hear the ‘peeoo’ being regularly repeated, this generally indicates several birds gathering together, probably looking for mates.
The call is the usual identifier, because although the adult cuckoo is bright metallic-green and white, with distinctively striped underparts, they’re surprisingly difficult to spot. I’ve heard them countless times, but only seen one once, in a boatyard, where it stood out. Mostly, they’re hidden amongst forest foliage and scrub. They’re prone to fly into windows, and many people only become aware of their gorgeous iridescence, when they find one stunned or dead beneath a large window. The best chance of seeing one alive is when they’re seeking kowhai moth caterpillars in kowhai trees or hunting the black hairy caterpillars of the magpie moth.
Pī pī wharauroa are the smallest of all cuckoos: 13-18cm long, with a wingspan of 25-32cm, weighing about 25g. There are several subspecies spread over Australia, Indonesia, New Caledonia, PNG, the Solomon Islands and Vanuatu. Our endemic form winters 3,000+ km away in the Bismarck Archipelago (New Guinea) and the Solomon Islands, before flying here to breed. It also has the distinction of being the most southerly ranging, brood-parasitic bird species in the world, with its range extending to at least 46°S.
The Ma ori name may refer to the bird’s typical habit of laying its eggs in other birds’ nests and not caring for its young: pīpī (chick) wharau (temporary structure/nest) roa (to delay). This pretty little bird is a nest parasite: in November she lays a single egg, generally in the nest of a grey warbler, removes one of the existing eggs and then abandons hers to its fate, before moving on to another nest and repeating the process. We don’t know how many she lays altogether.
Pī pī wharauroa breed in or near forest and scrub, and in farmed and urban areas – wherever riroriro are plentiful. The egg takes 15-16 days to hatch and after hatching, the baby cuckoo ejects the host nestlings from the nest, and mimicking the call of a grey warbler chick, demands food from its obliging ‘foster’ parents. The unsuspecting birds, unaware of the imposter, accept it as their own and raise it. After 19 days it fledges and the riroriro feeds it for up to 28 days after leaving the nest. By adulthood, it dwarfs its tiny grey warbler foster parents growing to nearly four times the size.
Fortunately for the fate of grey warblers, shining cuckoos generally arrive after they’ve brought up their first brood, which is just as well, because a study in Kaikoura found that 55% of second brood nests had been parasitised. Apparently cuckoo’s dark egg serves to protect it from other cuckoos visiting riroriro nests. A test using model eggs of different tones showed that pī pī wharauroa removed eggs of brighter colours. Occasionally, they lay their eggs in the nest of fantails, house sparrows and song thrushes.
Pī pī wharauroa feed predominantly on invertebrates. Like most cuckoo species, they have the incredible ability to eat toxic insects, such as hairy caterpillars, particularly those of the magpie moth, and ladybirds, which many other birds avoid. They are one of the few New Zealand birds recorded eating monarch butterfly caterpillars (which contain cardiac glycosides, a powerful toxin that impacts heart function), and taking red admiral butterfly caterpillars from tree nettle.
Its gizzard has a soft, thick lining which catches the caterpillar spines; some of the lining is later shed and regurgitated, removing the toxic hairs. It’s still something of a mystery how shining cuckoos are immune to these toxins.
While pī pī wharauroa are (for once!) not particularly threatened, they’re susceptible to a number of humancaused dangers. I’ve already mentioned their flying into windows, something which can be avoided by applying window decals, which enable birds to see the glass and avoid flying into it. The usual suspects of introduced predators are an ever-present danger and shining cuckoos often fall prey to cats when foraging for insects. Pet cats should be kept indoors or have a ‘catio’.
However, shining cuckoos are very rare on the Chatham Islands, even at sites where Chatham Island warblers are abundant. They are possibly an overflow from New Zealand, but they could be an isolated subpopulation which only breeds on the Chatham Islands and if that’s the case, then they’re perilously close to extinction. Moreover, in spite of not being in much trouble in New Zealand, their numbers appear to be reducing overall, which may be due to deforestation in their winter homes.
If you go outside for a few minutes one summer afternoon, take time out to listen for this lovely little bird. I’m sure you’ll hear one, but I suspect you won’t see it!
Shining cuckoo | Pīpīwharauroa. Adult feeding on gum leaf skeletoniser (Uraba lugens) caterpillar from gum tree. Mapua, Tasman district, October 2016. Image © Rob Lynch by Rob Lynch.
