In the far north of New Zealand lie the rugged Poor Knights Islands, off-limits to terrestrial tourism, but surrounded by a stunning marine reserve containing one of Jacques Cousteau’s top ten dive sites. Why are these prismatic waters so rich with life? One likely factor is the abundance of seabirds that breed here, bringing nutrients they’ve consumed at sea and depositing them on land—with a cascade of effects on the coastal ecosystem.
It’s a rare privilege to see the underwater world around this archipelago, but even luckier is being part of a research expedition with a special permit to go ashore. Along with the Northern New Zealand Seabird Trust and Radio New Zealand’s Alison Ballance, I caught a ride on a dive boat to one of the Poor Knights Islands to study its influential (yet elusive) seabird inhabitants.
Buller’s shearwaters or rako are slender seabirds that traverse the Pacific and can be seen off the California coast (where they’re sometimes called New Zealand shearwaters), but their only nesting place worldwide is right here. Aside from enriching the Poor Knights ecosystem with their guano, the birds have also used their clawed feet to engineer a unique landscape. The forest floor here is largely a forest crust, with a vast city of burrows beneath.
Visiting the home of the shearwaters is a multi-sensory experience. You land in a dinghy on sharp volcanic rocks with a surge and a splash. You spend a couple of hours lugging loads of gear across the craggy shoreline, encircled by a 360-degree technicolor vista of towering cliffs and sun-filled waters. You climb into the shady forest and set up your tent, smack in the middle of a neighborhood of musky-scented nest burrows. (They seem to be deserted during the day, but you know better).
You spend mornings and afternoons struggling up steep forest slopes, tracking down audio recorders to switch out their batteries and SD cards—which requires stepping gingerly on thousands of shearwater burrows, and taking great pains not to break through their roofs. You lie face down in the leaf litter and reach your entire arm into many of those burrows, each time hoping to feel a spirited nip from the fluffy chick you’ll be measuring, rather than the reptilian bite of a lurking tuatara.
But perhaps the most remarkable sensory dimension of a Poor Knights seabird expedition is the soundscape. When the sun goes down and darkness falls, the adult shearwaters fly in from the ocean, crashing through the canopy and landing with spectacular thumps on the forest floor. After scuttling to find their burrows and feed their chicks, they spend the rest of the night making a grand old racket of yelps and cackles all around your tent. Just before daybreak they climb up boulders and trees, launching themselves back through the trees and out to sea, leaving stillness behind—soon broken by the musical dawn chorus of bellbirds.
If you’re wishing you could experience this for yourself, great news! Ballance has produced a transportive RNZ episode about our trip. Take a few moments to listen in (and don’t miss her written story, which includes some photos of the sketch biologist in residence).