Shining cuckoos deserve refuge despite 'offensive' habits

An adult grey warbler enslaved by a young shining cuckoo chick, twice its size, constantly demanding food. Photo / Mark Maultby

It's the time of the year when we hear the cuckoo sing.

The call of the shining cuckoo, or pipiwharauroa (Chrysococcyx lucidus), is a series of "coo-ee coo-ee" notes, with a descending "tsss-eww" or two at the end.

Right now they are staking out territories, listening for the calls of grey warblers and waiting for the warblers to nest.

What happens next is repellent to most people. The female cuckoo scares the warbler off its nest, grabs an egg, and lays one of its own in its place.

The cuckoo chick hatches before any of the warbler eggs do, and its first act is to push all the remaining eggs out of the nest.

Then for weeks it begs constantly for food from both of its warbler foster-parents, even though it's bigger than them.

This is the only way shining cuckoos can reproduce. Adults will even pull warbler chicks out of the nest to encourage the hosts to lay another clutch for them to take over.

How do we protect innocent grey warblers from this parasite? That's the wrong question.

Every animal preys on something else and we can't change them just because it offends our sensibilities.

When we put ourselves in the position of other species and imagine how we'd feel if it were us, we're getting in the way of truly understanding them.

Shining cuckoos are remarkable birds. They're beautiful, small and iridescent green with striped underbellies.

Every winter they migrate to western Indonesia and New Guinea, but somehow find their way back to the very same territory in New Zealand where they sang in the spring before - without the help of Google Maps.

Rather than judge individual cuckoos, we should think in terms of species and populations.

The grey warbler is the most widespread of our birds, found almost everywhere including suburban gardens.

It has coped well with the arrival of humans in Aotearoa and the destruction of our forests.

Shining cuckoos are less common than warblers and are not present in much of the South Island. Worryingly, it looks like their numbers are decreasing, despite their hosts being so common.

Instead of condemning this beautiful native bird with its springtime call, maybe we should be worrying that there are not enough of them.

One possible cause of their decline is forest clearance in Indonesia and New Guinea, which destroys shining cuckoo wintering grounds.

A big driver of that deforestation is the planting of lucrative palm oil plantations.

This isn't a remote issue that doesn't affect New Zealand.

As well as saving orangutans, palm oil labelling on our foodstuffs might help the shining cuckoo, and let us keep hearing its call every spring.

- Dr Mike Dickison is curator of natural history at Whanganui Regional Museum.