Rifleman Series: Part 7 - Survival

Zealandia, the 8th continent consists of New Zealand and the Pacific islands. It separated from Gondwana more than 80 million years ago. This is before the first mammals took over the terrestrial world 65 million years ago. As such, mammals did not colonize the early New Zealand until humans brought sheep, goats, rodents and mustelids with them.

The native New Zealand birds, which evolved without the need to avoid mammalian predators, are naturally defenseless against them. Many nestlings of small birds are affected by tree climbing rats. And so the population of the unique bird life of New Zealand are threatened. The Department of Conservation hence developed a plan to remove mammalian predators by using poisons with species-targetted dosages, self-resetting kill traps, and fences around forest reserves.

Our field site, the Boundary Stream Mainland Island is the first of its kind that receives intense predator control efforts since 1996. Since then, predator control and translocation efforts have resulted in the recovery of many native New Zealand birds in this forest.

In January, the juvenile tītipounamu are becoming more agile and brave. I often start hearing a group coming my way from inside the bush and appearing on branches near me, giving me looks of wonder. Sometimes they would even fly right past my shoulder! This is what I mean by having no instincts for avoid mammals. Another interesting observation is that birds here also fly very loudly. They were not being selected to have silent flights. And it didn’t take us much practice to differentiate the wingbeats of different species. The wing beats of a New Zealand wood pigeon (kereru) are slow and whooping. A tui’s flight sound is quick and powerful. And the tītipounamu’s is like a flutter of the heart when you fall in love. I think these birds have made their way into a soft spot in my heart!

But as weeks goes by, the juvenile groups are reducing in numbers, so they are harder to find and track. The parents are also seen less feeding them. So it can be hard to tell which groups of juveniles belonged to which parent pair if we don’t band them immediately. This is another time-critical challenge for us, where we have a small window of when they are independent enough to explore but not too dependent that they stay very closely in their group, to catch and band them.

Here on the left is a juvenile male with streaked head and green rump, and on the right is an adult male parent with full green head.

In the next blog post in this series, I will wrap up my field season and ponder about the beauty of working as a wildlife field biologist. It has been a insightful journey so far. Thank you for following my story and I hope you enjoyed this little series where I document the first fieldwork season of my PhD. The next and last post will be up on 18th February 2019!