We caught up with Tim, a ranger on the front lines of the Save Our Iconic Kiwi initiative. This is the sixth in a series following the work he’s doing to save the Fiordland tokoeka (kiwi). Tim and his team have been studying the population of Fiordland tokoeka at Shy Lake to find out how to best protect the kiwi from predators like stoats. The team 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.
After an hour counting radio transmitter beeps with the snow falling around us, ranger Hamish and I head off on our rounds of the nests. We visit the nest of Cake and Candles, a pair named for their birthday capture. A quick glance into the shallow nest reveals another chick! The second chick of the programme, it looks like it hatched a couple of days ahead of our predicted date and is still pretty young, so we leave it be and carry on.
An hour later I arrive in the territory of Sinbad Colby, eager to check on the progress of our first chick, Waimarie. The tiny transmitters carried by fresh chicks do not give us the “mortality” information of larger transmitters, which tell us if the transmitter (and therefore the bird) has stopped moving for 24 hours. So I don’t know what I’ll find as I follow the signal through dripping scrub and scramble up a mossy bluff a few hundred metres from the nest. It’s not good: all I find is the back half of a chick lying on a mossy ledge. The head and front of the torso have been chewed off and most of the organs eaten. It looks to me like a mammal rather than a bird has been eating it, but that’s all I can tell for sure. The focus on the head and guts fits a stoat attack, but there are no bite prints and I can’t see any hair, scat or prints nearby to give a clue as to the identity of the predator. Dispirited, I bag up the carcass, make some notes and move on.
At Sinbad Colby’s nest, the videos show that Waimarie last left the nest four nights previously. Based on studies of other tokoeka, this would be a normal age (about 20 days) for a chick to leave home and the carcass looked pretty fresh – I think it’s only happened in the last day or two. When we return to town, the carcass is sent away for analysis. A post-mortem examination of the chew marks confirms predation rather than scavenging after death; while genetic testing of swabs from the wound site indicates the classic culprit, a stoat. Poor Waimarie didn’t stand much of a chance.
This trip also sees us run the first round of tracking tunnels at Shy Lake. In order to get robust evidence on our efforts to save kiwi chicks, we need to be able to quantify the numbers of pests in the area. Three weeks ago, ninety black plastic tunnels were dispersed around the Shy Lake area. Each had a length of card inside, with a patch of ink in the centre and a small plastic cage containing a piece of rabbit meat. Now we return to the tunnels, remove the cards and look for prints of any stoats that may have been attracted by the meat to run across the ink patch. We insert a fresh card into these and a further sixty tunnels, this time with peanut butter as the lure to attract rats. These will be collected the tomorrow. Rangers Hamish, Heather and Anne put in a great effort on some long, physical days of bashing through wet bush up hill and down dale. The next round will be in February, after this year’s stoat kits (young) have dispersed from their natal dens.
With the tracking tunnels behind us, the sun comes out and it’s the perfect opportunity to revisit our new chick from a couple of days ago. From under its father Cake I remove a perfect little miniature, Muffin. This one is less wriggly than Waimarie last week, maybe because it’s broad daylight and it’s past its bed time. It’s no less cute though. We return it to the nest and wish it better luck than Waimarie had.
This is the sixth in a series of posts about Tim’s work, follow the Conservation Blog to keep up to date on his progress.