Back to the Ruahine: Iron Gate hut

[After an enforced absence because of illness, I've recovered enough to resume visiting the Ruahine.]

Shortly after midday I waded the Oroua and made my way along a broad boulder beach on the river’s true right[1]. On the opposite side a huge slip had scarred the forest, sending massive broken boulders tumbling into the river. The slip had deteriorated since it first came down several years ago, taking out the track; a rudimentary bypass cut around the top of the slip is almost vertical in places, swampy in others, and a lot of effort for very little progress up the valley. The original track was significantly damaged in other places as well, so the river offers an easier route to Iron Gate hut — but only if it’s running clear and not too high. The river route also offers the possibility of meeting whio, and that alone was enough for me to prefer it over the sidle track.

I’d walked that section of river in May but had seen no whio — a poor reward for numb feet. At least the water wasn’t as cold this time, although most crossings were close to knee deep and the flow powerful so I crossed carefully, taking no risks. Intermittent cloud and a cool wind took some of the heat out of the sun, and I was thinking how the weather could hardly have been better for tramping when a sound made me look across the river. There, standing on top of a great boulder that only just emerged from a deep channel, was a female whio.

I placed the pack on the ground and retrieved the camera, photographed her, and moved slowly and at an angle towards her, watching her out of the corner of my eye to check for any signs of alarm. She wasn’t bothered. As I moved closer she carried on preening, and when I was close enough to ensure I’d have enough of her surroundings in the frame, I sat and watched her and photographed some more. After a quarter of an hour or so I got slowly to my feet and started edging away, back to my pack. Immediately, she stepped off the rock into the water and started swimming — not away but towards me, calling several times. She swam right up to the water’s edge and circled, and I stopped and photographed her and recorded a short video clip. Apparently satisfied, she swam back across the river to her rock and resumed preening and taking little sips of water. I neither saw nor heard any other whio and I wondered why she was alone. My best guess was that she was taking a break from incubating a clutch of eggs and her mate was guarding them. Apparently, only females incubate the eggs[2] but I wonder whether males will take over briefly while a female feeds and preens? Maybe the eggs can withstand short periods without being incubated?

If my speculation was correct, perhaps I hadn’t missed the peak period for seeing whio chicks at the adorable fluffy stage after all. I’d been laid low by RSV for over a month, coinciding with peak hatching time, but maybe I was too early and the eggs hadn’t yet hatched? Robb and John and I had seen young, fluffy chicks in the Maropea river in mid December a few years back, so my chances hadn’t completely disappeared.

At the hut towards evening, grey cloud closed in and grew darker. I took crackers and cheese and walnuts and the camera and binoculars upstream a few hundred metres and perched on a boulder to watch the river, to listen to the white noise of the rapids and a strange, deep thumping where the water plunged over a small fall into a foaming pool, to wait and hope that a whio might appear or some odd and interesting insect might flutter or creep into view. Nothing out of the ordinary appeared but sometimes it’s enough just to enjoy the possibility, and this was one of those times. I returned to the hut and while I was writing at the big table I heard rain on the roof. That sound can leave me anxious about river crossings but I knew I could take the sidle track back to to the road if necessary and the one potentially significant crossing, Tunupo Creek, would be unlikely to rise to an unsafe level unless the rain set in and persisted overnight. I carried on writing, happy to be safe and comfortable and well fed in the hut, and after an initial heavy shower the rain stopped. If it returned during the night, I wasn’t aware of it and by dawn the river appeared unchanged.

I sat on the verandah, drinking tea and watching the dawn sky lighten. The cloud had that look that suggests it wasn’t going to last — a gradual brightening that might at any moment transition into patches of blue sky. High in the forest on the far side of the river a deer barked several times. I didn’t bother with the binoculars and would have been unlikely to have seen it even if I had. I’d checked the river at first light but had seen no whio so I decided to walk back down the river, which I assumed would be no harder than the walk up it the previous day — probably very slightly easier because I’d mostly be crossing with the flow instead of against it. Perhaps the whio would be active and more obvious earlier in the day; to have seen the female preening in the middle of the day had surprised me.

I packed, cleaned the hut, and set off. Twice I saw tuna (eels); one I thought at first was a sunken log and I’d resumed walking when I saw it undulate into a deeper part of the pool. Further downstream, a small brown trout patrolled a backwater pool connected to the main river by a shallow flow that almost certainly wouldn’t allow the fish to escape its pool. Without significant rain, the pool would shrink and heat up and the little fish would asphyxiate if it hadn’t already been eaten by a shag, but I could do nothing to help it escape. Some people consider trout — introduced in Aotearoa — to be pests, and it’s unarguable that they must have affected native freshwater ecosystems, but recognising the impacts of an introduced species and feeling empathy for an individual of that species are not incompatible.

At the Tunupo Creek confluence, I stopped briefly and through binoculars scanned the riverbed ahead. Nothing. A little further on, I came to the place where I’d watched the whio the previous day but she was nowhere to be seen, nor did I see any whio on the final reach before the track climbed out of the riverbed. I stopped there and had an early lunch and looked out over the limpid river with its deep blue-green pool at the upstream bend and a stretch of crystal clear water surging downstream and breaking into rapids as it sped down the valley. Sunlight filtered through beech forest; a little male miromiro flew close to check me out but didn’t linger long enough to be photographed.

I could hardly have wished for a better return to the Ruahine.

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Notes:
1. The true right of a river is on your right as you're facing downstream
2. See the information about whio on New Zealand Birds Online

Photos (be sure to click them to see them properly):
1. The female whio stretching during preening. (iNaturalistNZ record here)
2. A riroriro (grey warbler; Gerygone igata) not far from Iron Gate hut. This was one of several riroriro (at least three), one of which was collecting lichens and moss, presumably to build a nest. (iNaturalistNZ record here)
3. I'd seen a great many small flies swarming around the rock on which the whio stood but I hadn't paid much attention. On checking the photos at home, I saw that these were what New Zealanders call sandflies but which are better known internationally as blackflies (Simuliidae). In addition to those flying, many were head down, feeding on her feet. She seemed to ignore them — something I'd have found impossible to do. My younger brother described them as 'dreadful creatures' and wondered whether the whio's behaviour when she swam towards me was because she was asking, 'Hey mate Got any Dimp with you?' (Dimp was the classic formulation of deet-based insect repellent.)

Photos and original text © 2026 Pete McGregor