You might imagine white sandy beaches and blue seas and skies when you think of the Cook Islands, but for Hugh Robertson, who’s been involved in kākerōri recovery there since 1987, the reality is quite different.
Only 29 birds remained in 1989
In 1987, Hugh was working with Dr Rod Hay at the Department of Scientific and Industrial Research, who had previously identified the kākerōri as one of the most endangered birds in the South Pacific. Rod and Hugh hatched a plan to save the kākerōri from extinction. By the time Hugh came to DOC in 1989, they had set up a recovery programme for the birds, whose population was dwindling with just 29 remaining. They had become one of the ten most rare birds in the world.
Kākerōri, otherwise known as the Rarotonga monarch, is endemic to the Cook Islands and is preyed on by ship rats. Through the annual efforts of the recovery programme – a mix of locals, ex-pats, and volunteers using rat control methods developed in Aotearoa – the kākerōri population reached 100 in 1995. Hugh and Lynn Adams of our Biodiversity Group are hoping to crack 500 in the COVID-delayed census, which is happening right now.
Like being a ranger, just hotter and sweatier
The Cook Islands might sound like your dream holiday location, but Hugh says the mahi is pretty similar to what a lot of our own biodiversity rangers do in the field in Aotearoa.
“It’s a lot of sweat, mud, and mosquitoes,” says Hugh.
Many of the species conservation problems on South Pacific islands stem from the same ship rats and feral cats that have wreaked havoc on native bird populations in New Zealand. The recovery programme team transferred rat control lessons learnt on our motu to a different setting and upskill locals in activities like mist-netting and colour-banding. Hugh notes that there’s a high turnover of local staff so he has conned DOC people to join them in beautiful Rarotonga – without mentioning those mozzies or the steep hills!
Hugh’s travel is usually funded by external organisations and sometimes self-funded, and he’s been known to use his annual leave to go and work on the recovery programme.
Kākerōri: they’re just like us!
Hugh says that the best thing about working on the recovery programme in Rarotonga is the experiences he has with the people he works with, who share a passion for conservation and this special endearing bird.
“One of the quirky things is that, like me, the kākerōri changes colour from orange to grey with increasing age.
“The kākerōri has orange plumage in its first two years, then a mix of orange and grey in its third year, and finally grey from four years onwards.
“This age-related change was not known until we started our work – it was thought that males were grey, and females were orange. This misconception arose because rats killed most nesting females when they were incubating or brooding chicks at night, so older males often ended up with a much younger partner each year.
“Kākerōri, especially young orange ones, are attracted by human voices. When we’re working in remote areas, the less inhibited of us call out phrases like ‘party, party, kākerōri’ to attract them to the vicinity of our mist nets and playback systems.
“We had a bit of a party when their population got to 100!”
Working together to achieve conservation outcomes
“It’s really encouraging to see so many organisations and dedicated people tackling conservation problems in the South Pacific,” says Hugh.
“When we started this project in 1987, very little bird conservation work was happening in the region and many species were going down the gurgler. The success of our project has encouraged others to manage more endangered bird species – the Rimatara lorikeet was translocated to Atiu island soon after it became apparent that our translocation of kākerōri to Atiu was a success, and in Tahiti a closely related species’ population was down to the 20s but has now reached over 100 birds through intensive rat and exotic bird control.
“It’s especially encouraging to see the New Zealand methods of eradicating rats from Islands being applied to eradicate rats from larger and larger atolls in the South Pacific to allow nesting seabirds to once again thrive.”
DOC is currently in discussions with Cook Islands authorities about the possibility of attempting the eradication of rats from some atolls in the northern Cooks.
Check out Te Tauranga o te Kākerōri on Facebook, and this video from Cook Islands TV News about the work Hugh and other volunteers do on the ground.
We’re eagerly awaiting the results of the kākerōri census that Hugh, Lynn and other DOC volunteers are currently doing in the Cook Islands.