Kiwi Census Data Returns Promising Results
Mount Bruce, Masterton:
Monitoring at Pūkaha has identified 12 wild kiwi alive and well in the reserve, including several pairs. The last census in 2018 identified 18 wild kiwi in Pūkaha forest.
Following the devastating loss of six monitored kiwi in the Pūkaha forest during the Level 4 lockdown and the inability to conduct a traditional ‘Kiwi Call count’ due to Covid restrictions, Pūkaha Mount Bruce has turned to technology in order to obtain an estimate of the wild population of kiwi in the 942ha reserve.
A total of 15 acoustic recorders programmed to detect kiwi calls were deployed across the reserve to record this elusive nocturnal bird. This high tech means of detecting wildlife has been used previously by Pūkaha for broader biodiversity surveys, including the recent discovery of long tailed bats, but never before has it been used specifically for kiwi calls at Pūkaha.
The loss of six birds to ferret attack during the lockdown was heart breaking for the team at Pūkaha, who have worked so hard to protect these birds and to support the growth of the wild population of kiwi in the region that were first reintroduced to the forest back in 2005.
The reserve has had previous losses of wild birds to ferret attacks over the years, but has remained committed to continuing with the project and the regions dream of having a sustainable and growing kiwi population in this special forest. “We had such a great run, with very few loses for several years due to improving techniques and technologies and fantastic collaboration from neighbouring farmers and the regional councils. We were feeling great about the low number of known kiwi deaths. Anticipation had been building leading up to the annual kiwi call count and everybody wanted to know how the wild kiwi population was getting on”, said General Manager Emily Court.
“After we discovered the loss of six out of only seven birds with radio tracking devices we knew that there was a possibility that the toll could be higher and we had to find a way to try and conduct a census despite the cold wet weather and restrictions imposed due to Covid-19” said Court. Biodiversity partners, Boffa Miskell were happy to come to the party with a set of special acoustic recorders to deploy.
With the help of the local DOC team Pūkaha set about getting the recorders in place at strategic locations across the landscape. Bad weather followed by a full moon made the timing of getting the recorders all out a little tricky but the team got there in the end. By using this technology rather than having people sit out at night listening for kiwi calls meant that we could cover territory that is normally too dangerous, which is one of the major benefits of using recorders over the traditional method of conducting a kiwi census. “Pūkaha has some very steep and dangerous ridges and gullies that are just not safe for people to venture to in the dark”.
Once the recorders were brought back in around 1200 hours of recordings were analysed with the help of some smart technology and a specialised team in Auckland.
During this survey period, 52 North Island brown kiwi calls were recorded on acoustic recorders. This included 39 calls from males, 13 from females, and 10 duets (male-female pairs calling to each other). These calls could be made by the same or different individuals, so determining the exact number of kiwi present is not possible. Young kiwi under two years old do not generally call so wild born chicks from the last few seasons are also not detectable yet.
With the calls that were recorded during the survey the Boffa Miskell team have been able to pinpoint the location of at least 12 different kiwi, including several pairs.
Confirmation that there are wild kiwi in the forest, especially pairs that are likely to have been breeding, was a huge relief to all involved. The last census carried out in 2018 identified 18 adult birds. This would indicate that wild population has been doing well and despite this devastating loss the population has not dropped significantly.
Today marks a very significant day for Pūkaha since the lockdown, Kakama, one of the most prolific breeders in the forest and the last remaining bird with a radio transmitter attached is sitting on an egg and rangers will be going in to uplift the egg and bring it into the hatchery. For the last couple of years Pūkaha made the call to let the wild birds be wild and to not intervene in their natural breeding and hatching process, but this year we feel it is appropriate to give nature a helping hand.
Operation Nest Egg, the name given to the process of uplifting wild kiwi eggs and raising the chicks to 1.2kgs before releasing them is known to improve survival rates of chicks significantly. Kiwi chicks have to fend for themselves from the moment they are born so giving them a chance to grow bigger and stronger before releasing them increases their chances of survival markedly. As a partner to Kiwis for Kiwis ‘Operation Nest Egg’ programme Pūkaha has an important role to pay in Aotearoa’s plans to turn around the population decline. Last year more than 20 kiwi chicks were successfully hatched for conservation projects around the North Island and returned to their home reserves. This year breeding has already started and the Pūkaha team is gearing up for another big season.
It seems appropriate that this week, NZ Conservation week, marks a milestone for the wild kiwi population at Pūkaha. We are getting back up and forging ahead with goals for this region. Conservation and working with wildlife has huge ups and downs but we can’t give up, for the sake of the remaining birds and to honour all of those who have poured their hearts and souls into this project over the years. We need to do it for them.