Kakapo’s strange behaviour fills the night

Whenua Hou’s light-aircraft landing beach, where there was a village of European sealers, their Maori wives and children in the early 1800s. PHOTO: NEVILLE PEAT

The booming

The largest of Rakiura’s 170-odd satellite islands and islets lies 4km off the northwest coast, the edge of Foveaux Strait. This is Whenua Hou, 1400ha, dubbed Codfish Island by the early European sealers. For centuries Maori hunter-gatherers have used the island as a seasonal stepping stone to the southwest breeding grounds for titi, the sooty shearwaters that nest in the deep south in their millions. More recently, Whenua Hou has become better known as a wildlife sanctuary of international importance, with the critically endangered parrot, kakapo, taking centre stage.

The island is more than simply wild and remote; it’s a Department of Conservation nature reserve with restricted entry. Which is why I was thrilled to be invited to go there in the course of researching a book about Whenua Hou, its human history and its exceptional natural values.

On a fine December day in 2013 we landed on the 500m-long sandy beach at Sealers Bay/Waikoropupu in a light plane out of Invercargill. At the Doc base, kakapo ranger Errol Nye briefed us about the rest of the day and half the night, starting with a look around the dunes area, where herbs like fennel and mint are aromatic evidence of the 19th century sealing. Nearby is the little river, Waituna, stained the colour of weak tea by forest tannin and organic material.

Landing at Waikoropupu/Sealers Bay. PHOTO: NEVILLE PEAT

Errol had in mind a hike to the island’s summit at 280m, Puke Hou, a steady climb for two and a-half kilometres, for a sunset view followed by an avian show that is music to the ears of any kakapo recovery worker — the booming of male birds to attract mates. So close to the summer solstice at this southerly latitude, the daylight would last till at least 10.30pm. Kakapo are nocturnal, so the show probably wouldn’t begin before about 11pm.

In the early evening our small group of Doc staff and volunteers reached the top of the island, donned jackets to stay warm, and lay about the summit’s rounded bare rocks in lowering sunshine. These boulders advertise Whenua Hou’s granite origins, which it shares with Rakiura, Fiordland and the subantarctic Snares group beyond the southern horizon. Surrounding us were rata and kamahi trees, stunted and windshorn by many a southwesterly gale, and shrubby Olearia tree daisies called teteaweka, a southern endemic species, bearing eye-catching swathes of purple-centred white flowers. They smacked of summer.

In no hurry, we wait at the summit till dusk descends then set off down to where green of a cryptic kind awaits.

Kakapo’s green plumage, mottled with black, yellow and cream patterns, gives the parrot superb camouflage. As we descend into taller forest, dusk turns to darkness. Then Errol calls a halt. We’ve reached a place on the trail near where a kakapo called Boss has chosen to construct his breeding bowl. Tracks radiate from it to guide females to the dance hall, his bowl. But we see none of his strange breeding strategy. On this moonless night, the darkness is intense, and with the breeze having gone down with the sun, the stillness is enshrouding. Except for the activity of seabirds.

Three carved pou overlook the river mouth at Waikoropupu/Sealers Bay. PHOTO: TONY PRESTON

Overhead, seabirds are calling as they return to their burrows in the peaty soil from a day at sea fishing. By the sound of them — "ti-ti-ti" — they are silver-grey mottled petrels, and their crashing through the canopy of low-forest announces their return. Whenua Hou hosts some 300,000 mottled petrel pairs, the largest of all colonies, and, curiously, their breeding range mirrors the granite geology. Only in Fiordland, Rakiura and The Snares do they nest. We can hear other aerial calls, too — "kek-kek-kek-kek" — which could be the relatively rare Cook’s petrel.

All of a sudden, our still, dark world is assailed by an intense sound, unbirdlike. It is so low and powerful it reverberates through our chests. The boom of kakapo. "Boss," whispers Errol. "His bowl’s about ten metres away". But which direction? The booming, two seconds apart, is surround-sound. On a night like this it might carry for kilometres. In bursts, he’ll keep up this calling till daylight arrives, as many as 10,000 notes a night, an age-old night beat. The booms emanate from air sacs in his chest, which he blows up then vocally releases. I’ve seen infra-red videos of booming kakapo looking like puffer fish with feathers. Boss is well hidden this night and we’re not going to go closer.

But then there’s another presence. It’s in the air, passing close near head height, all but invisible — bats. They ghost past us, small and soundless. Mouse-sized, they spend a lot of time on the forest floor foraging for insects, seeds and fallen fruit with a jerky gait, using folded wingbones in place of front legs, like crutches. What makes this encounter special is that the lesser short-tailed bat is as endangered as the kakapo, the parrot of the night.

The booms continue, and they alternate in bursts with a metallic, higher-pitched ringing call, onamatopoeically known as "chinging". It’s thought the chings might help females track down the males.

If kiwi, "honorary mammals" of the avian world, are the most improbable of all birds, kakapo surely take second place. This is not surprising when you know that Aotearoa New Zealand, isolated for eons from terrestrial mammals other than bats, became an experimental arena for birds, a laboratory for outlandish avian design. Consequently, kakapo are unlike any other parrot species — the heaviest of their kind, owl-faced, flightless, long-lived. Life expectancy is an impressive 90 years.

Next morning, before the flight back to Invercargill, I look into another extraordinary dimension of Whenua Hou. Physical evidence is scarce but an archaeological dig in 2007 turned up a rich and illuminating assortment of Maori artefacts going back to the 14th century and European artefacts consistent with early 19th century occupation by sealers and their Maori wives and children — ostensibly the first planned bicultural settlement in Aotearoa.