Fiordland Kiwi Diaries 20: Shy Lake’s second season

We’re on the front lines of the Save Our Iconic Kiwi initiative. This is the twentieth in a series following the work being done to save the Fiordland tokoeka(kiwi). Our ranger Tim and his team have been studying the population of kiwi at Shy Lake to find out how to best protect them from predators like stoats. They have captured a number of kiwi and put transmitters on them, and are now monitoring them through the breeding season to find out how well the adults and chicks survive without pest control.

Here at Shy Lake, we’ve wrapped up our second season’s monitoring of kiwi breeding. It’s another grim tale: of the 24 chicks we monitored this season, none survived.  Two died very young from natural causes, which is fairly common with kiwi. Two disappeared within the first four nights since they started emerging from the nest.  We don’t know for sure what happened to them, but both nests had stoats visiting. Ten were fitted with transmitters, and all of these ten were killed and their carcasses stashed by stoats.

It’s pretty gutting to be observing a beloved native species and these cute little chicks getting hammered like this. 

I often get asked how I keep my motivation. For me it’s about the big picture: we’re working to make a real difference to big numbers of kiwi across an even bigger landscape and it’s not going to happen overnight. My monitoring project is there to provide the ‘proof in the pudding’ of our predator control. And now I have something to get excited about: Save Our Iconic Kiwi’s first Fiordland predator control operation is planned for March 2020. We’re using aerial 1080 to protect the peninsulas north and south of Wet Jacket Arm, including the Shy Lake study site: 40 000 hectares in all, holding hundreds of kiwi. It’s an ambitious operation, the most remote attempted yet on the New Zealand mainland. We’ll need fine weather on both sides of the mountain divide, and minimal snow cover – it can fall at any time of year down here. Next autumn might feel like a while away, but we’re targeting the period that will provide the best and longest protection for the kiwi population in the area. How’s that, I hear you ask?

Many people will be aware that this summer and autumn just gone was a “mega mast”. Down here the beech seed is the big driver of pest populations, but everywhere you looked, plant life of all kinds were booming.  Every tussock was dropping seeds, flaxes had rank-on-rank of flower spikes, and the beech pollen drifted across the sky like smoke.  Nobody I talked to could remember seeing anything like it. Shy Lake has plenty of stoats but normally has low rodent numbers. Stoats don’t eat the toxin pellets, but they do eat rodents. The mega mast means rodents will gorge on all the seed and their numbers will grow this winter to much higher than normal levels. Come autumn, that will mean lots of toxin pellets eaten and every stoat in the area will have a high chance of eating a toxic rodent.

We chose the Wet Jacket Peninsulas area partly because the gnarly topography and water on three sides should slow down the rate at which stoats re-invade after the 1080 drop. Timing our drop for autumn is also designed to slow down re-invasion, as it will be after the peak period of stoat dispersal, when the juveniles leave their mothers in early summer and start running around all over the place. Later they’ll settle down a bit and we plan to take advantage of this to get the longest benefit from our drop. Past studies have shown in places like Tongariro, 1080 drops have led to improved kiwi survival for the next two years. We’re aiming to get the same, and if we can pull that off we’ll meet our goal of getting the local kiwi population to grow instead of shrink.

At a personal level, it can’t come soon enough, but I’ve got to be patient.  Eyes on the prize. After a few months tied to my computer desk after tendon surgery, I’m itching to get back to Shy Lake and roam the hillsides in search of the elusive kiwi. The first birds are already nesting, and soon it’ll be time to head out with a backpack of tracking gear and trail-cams, and get a look into their world.