Monitoring rock wren in an alpine world

Crystal Brindle, Research Assistant

I have recently lost myself in the practice of exploring lake basins, rocky cliffs, and mountain tops in search of a fleeting endangered bird that calls this rugged landscape home, the rock wren/tuke.

Rock wren can be identified by their upright stance and short tail. Credit: © James Reardon

This reclusive native is perfectly coloured to its mountainous environment, with moss green feathers and splashes of buttercup yellow under its wings. To monitor its nesting success, I’ve followed it into the alpine zone and created my own nest at Lake Roe.

Sometimes I have to stop and capture the remarkable beauty of my new home. Credit: © Crystal Brindle

My first trip into my new home, deep in the heart of Fiordland’s wild country, was beyond special. Wedged in the very outermost edge of the helicopter passenger seat I felt like I could almost reach out and touch the passing cliffs and forest.

Lake Roe, deep in the heart of Fiordland’s wild country. Credit: © Crystal Brindle

Clouds open, clouds close, a view here, a glimpse there: did I just see an idyllic valley of reflective pools or the most jagged peaks I’ve ever seen? Or, was it my imagination? Was that in fact a seven-tiered waterfall dropping from a snowy glacier to a deep and perfect pool hidden in silver beech forest? It can’t be. I didn’t know mountains even rose that sharply. That cliff can’t actually be that steep, this river can’t possibly snake its way through such a magical rock-strewn valley, and that waterfall absolutely cannot tumble from that lake in the sky all the way into this fiord below. Or can it? This blend of fantastical reality could only be possible in Fiordland and made monitoring rock wren nests even more incredible.

The evening sun dips below the horizon, casting its last red light upon the mountains surrounding Lake Roe Hut. Credit: © Crystal Brindle

Found only in small pockets across the South Island, it was assumed their alpine habitat kept rock wren relatively safe from introduced predators. Research examining nest success has since proven otherwise. Cameras have caught stoats scaling cliff edges and jumping metre-wide gaps to raid nests. Footage like this is a reminder that while alpine Fiordland is a place of discovery and excitement, it’s also a place of continual challenge and unexpected strength that all living things cultivate for survival.

Stoat raids a rock wren nest. Credit: Kerry Weston

Hugging the edge of a mountain my co-worker and I peer through sleety rain, trying to catch a glimpse of a tiny rock wren entering and exiting its nest hole in search of food or more insulation for warmth. How do they do it?! These 10 cm long birds weigh only 15 – 20 grams and yet inhabit a mountain landscape that is huge on any scale. Like miniature mountaineers they hop and fly up nearly vertical rock faces bringing food, feathers, tussock, or lichen to and from the nest no matter what the weather throws at them.

These awe-inspiring views can lull you into thinking this work is a walk-in-the-park. Credit: © Crystal Brindle

As snow begins to fall we shiver back down to our own form of shelter, pondering how the rock wrens and their nests will fare in such harsh and unpredictable conditions. As we sit in the hut, our main comfort comes from knowing our work will contribute to protecting this unique and resilient boulder hopping bird.

A rock wren surveying its rugged home. Credit: © James Reardon

To use this story as context for learning, take a look at the new DOC ‘Investigating Alpine Environments’ education resource for secondary schools. This resource is designed to introduce secondary students to New Zealand’s extraordinary alpine environments, and support them to take action to help protect them.