My name is John Ewen and I am one of the oldest of the researchers that work with the hihi on Tiritiri Matangi. I was a fresh-faced MSc student monitoring the hihi once they were released on the Island. The release was exciting and had gone really well, largely thanks to Mel Galbraith and a team of students from Glenfield College who planned and led the translocation.

I well remember that September day back in 1995. I was with John Craig and a bunch of supporters and visitors down in Wattle Valley excitedly preparing to let our group of birds go. The hihi were all very happy to get out of their transport boxes and into the forest. But I then had to return to Massey University and exams. I got back to the Island a month later to start my project. I was meant to be looking at how distance to a feeding station would affect how many babies a female hihi could raise. BUT there were no females! Well, a lot fewer than the 20 that had been let go.

What to do? First and foremost was anything to help these birds get a foothold in their new home. We had four females. Luckily each settled on a territory and I spent my days watching and recording what was happening. I set up temporary feeding stations nearby so that they had ample food, and nervously hoped. Breeding! It was full on. We had learnt previously about the crazy sex lives of hihi and this was certainly confirmed, in fact made more intense, because there were so many more males than females.

Studying hihi mating behaviour was also made easier on Tiritiri because the forest is relatively low and open. We found out that hihi hold the world record in promiscuous behaviour in birds! Anyway, six babies were produced that first breeding season, and four of these turned out to be precious females. 

The hihi population on Tiritiri has had two more helicopters full of birds from Hauturu-o-Toi since 1995. The next year we went back to Hauturu-o-Toi to do a top-up translocation and brought over 13 more birds.

After this point the population started to take off. It grew to about 70 adult females and around 160 adult birds in total. We have attempted to keep it at about this size and do so through harvesting mostly juvenile birds to establish new populations elsewhere.

In a further translocation, in 2010, we brought over 20 birds to see how easily we could integrate genetic diversity from Hauturu-o-Toi’s large remnant population into Tiri.

Tiritiri has also become the main source of exports of hihi to start up new populations. The first was to Zealandia-Karori Wildlife Sanctuary in Wellington in 2005.

That makes it 10 years since hihi were first brought back to the mainland of New Zealand, up close and personal to people in a major city, and they came from Tiritiri. I think that is special. Since 2005 Tiritiri has also provided hihi to Ark in the Park, Maungatautari, Kapiti and most recently to Bushy Park. As long as the Tiritiri population continues to do well the birds will continue to be harvested and spread to the best possible sites across northern New Zealand… and maybe further south? With climate change, who knows?

Our Tiritiri hihi have shown amazing resilience and, despite failing to establish in Ark in the Park, they have established, or are showing promising signs of establishment, in all other sites.

But is Tiritiri full? How many hihi could we have on the Island? These are tricky questions. We have not seen evidence for the population regulating itself, ie there is little evidence for density dependence. We have strong and positive population growth. This is, of course, probably artificial. The birds are intensively managed: we feed them; we give them nest boxes; we look after their babies by constantly looking out for and treating infestations of nest mites. As long as we keep responding to the increasing demand of these chores the population could keep growing.

Or could it . . ? We have had some bumps along the way. In 2006 an outbreak of salmonellosis was estimated to have killed 25% of the adult population. There is concern that these types of disease outbreaks might be facilitated by an artificially high density of birds combined with them congregating at feeding stations. Whilst we have little direct evidence for this, the Hihi Specialist Group and the Tiritiri managers have agreed to manage the population at about the 70 adult female level. This is to try and avoid increases in disease outbreak frequency and because the management level required is possible under current resourcing.

Hihi certainly don’t lack charisma. Over the years they have been near constantly studied and I am sure this is at least partly because of their character. From their sex lives to the meaning of their colourful plumage, from their diet to their parenting skills and most importantly how we best manage this population and species. Every individual is known from birth and tracked until death or translocation elsewhere.

This has resulted in six students completing MSc studies on Tiritiri hihi, five doing PhDs and two more currently under way. An amazing 52 peer reviewed scientific publications are out there based on this one population! Students and researchers come from many countries including New Zealand, United States, Britain, Ireland, Sweden, France and the Netherlands.