Little spotted kiwi translocation to Anchor Island

Abstract

Twenty little spotted kiwi (kiwi pukupuku) were translocated from Kapiti Island to Anchor Island in Dusky Sound, Fiordland on 17 April 2015. Fourteen of the kiwi were fitted with transmitters to enable their survival and health to be monitored for a year, to ascertain whether more kiwi will be translocated to reach a target of 40-45 birds. Signals from the transmitters were recorded remotely using Sky Ranger technology, as well as a ground check in August 2015. A gravid female and several males with good weights were captured. A team went to the island in late January 2016 to remove transmitters, where they found one chick and seven kiwi with good weights. A further 20-25 kiwi will be translocated to Anchor Island from Kapiti Island in autumn 2016 to meet the target of 40 to 45 founder birds.

Introduction

Little spotted kiwi were originally widespread in both the North Island and South Island but were rare in the North Island by the time Europeans arrived. They remained widespread in the South Island through the 1800s but gradually disappeared from the mainland leaving only a small relict population on D’Urville Island by the early 1900s. Five of these survivors were transferred to Kapiti Island in 1912 where they flourished. Management of this species over the past 20 years has reversed its decline due to the growth of the Kapiti Island population and transfers to other predator-free offshore islands and the Karori Wildlife Sanctuary. They are the smallest and hence most vulnerable of the kiwi species. The goal for their recovery according to the Kiwi Recovery Plan 2008-2018 is to increase the current wild population of 2000 birds by 50%.

Little spotted kiwi were once widespread in Fiordland in the 1800s and were returned to Chalky Island in 2010 after 100 years of absence. Sightings from staff suggest the population is doing well and this will be further substantiated with a monitoring trip using a trained kiwi dog in autumn 2016.

Little spotted kiwi were once widespread in the Dusky Sound area, and known to be present on Anchor Island in the late 1800s and early 1900s, as a result of an introduction by Richard Henry, although they would have died out once stoats invaded the island. Restoration of Anchor Island began in 2001. Already rodent free, the resident stoat and deer populations have now been removed from the island and biosecurity management is ongoing to prevent incursion events. Native species already successfully transferred to Anchor Island include kakapo, tieke (South Island saddleback), kakaruai (South Island robin) and mohua. The translocation of little spotted kiwi to Anchor Island was considered valuable for the following reasons; little spotted kiwi once existed on the island, the island has security against predators, the range and security of the species is increased.

The Kiwi Recovery Group was concerned that the peaty soils of Anchor Island may not support a population of little spotted kiwi therefore recommended  the use of transmitters to monitor the health and weight of a proportion of the founder population before completing the translocation in years 2 and/or 3.

Methods

Kiwi practitioners captured birds on Kapiti Island using trained kiwi dogs several months prior to the translocation. Temporary transmitters were attached to the birds and swabs and blood samples are taken for disease screening purposes. Several trips were undertaken to capture enough kiwi to ensure a good number could be caught when the transfer day came. On capture day a catching team including Ngāti Toa Rangatira, Department of Conservation staff and volunteers captured little spotted kiwi on Kapiti Island by tracking transmittered birds and searching known daytime burrows with a certified kiwi dog.  Each kiwi was placed in a specially designed transfer box and transported by boat from the island to the mainland. The kiwi were then driven to Wellington where they were kept overnight. The kiwi were loaded onto a plane the following morning bound for Queenstown airport. From there the birds were met by a helicopter and flown to Te Anau, where new transmitters were put on them, before being flown onwards to Anchor Island. The kiwi were released into natural burrows on the island.

The birds were monitored using Sky Ranger technology every 6 weeks. The signals were read from a fixed wing aircraft flying over the island in a grid like pattern. This provided information around estimated locations and mortality signals. Midway through the year of monitoring a team assessed the weight and condition of the kiwi by capturing and handling them. In January 2016 the transmitters were removed.

Results

Twenty little spotted kiwi were released into natural burrows on Anchor Island on 17 April 2015. The 20 birds consisted of nine adult males, eight adult females, and one sub-adult of unknown sex. Fourteen of the birds had transmitters attached however one transmitter had low power and was not heard from again.

Sky Ranger flew over Anchor Island four times from April to December 2015. All signals were picked up at least once, however during the last flight in December there were 6 transmitters not found. One of these was found in January 2016.

Jane Tansell and Hannah Edmonds visited Anchor Island from 26 – 31 August 2015. A total of four kiwi were handled, one female and three males. The second kiwi handled was a female and was obviously gravid (had egg developing inside her), therefore she was carefully put back into the burrow and no more females were handled as a consequence. Three signals were not heard, however Sky Ranger picked up two of these in September.

Sanjay Thakur and Hannah Edmonds visited Anchor Island from 26 January to 2 February 2016 to remove transmitters from the kiwi. Seven kiwi were captured, weighed and had their transmitters removed. One small chick was seen escaping a burrow with the male suspected of breeding in August. This chick was probably about 1 to 2 months old. There were no signals from five of the kiwi on the island, even though the team covered the island several times. 

Table 1. Individual data for monitored kiwi on Anchor Island 

Conclusion

Results show little spotted kiwi are breeding and maintaining healthy weights, therefore 20 to 25 little spotted kiwi will be translocated to Anchor Island from Kapiti Island in 2016 to achieve the target of 40 to 45 founder birds.

Locating kiwi with Sky Ranger technology, as well as on foot was more difficult than anticipated, due to the undulating terrain as well as the low power of the transmitters. Five transmitters remain on little spotted kiwi on the island. These may not be recovered and will eventually fall off in time with no adverse effect to the birds. Transmitters will not be used on the 20 to 25 kiwi to be translocated to Anchor Island in autumn 2016. A cost benefit analysis would have to be done regarding the use of transmitters for future translocations of little spotted kiwi on islands in Fiordland. 

Acknowledgements

Thank you to the Fiordland Lobster Company for supporting this project, along with the Fiordland Conservation Trust. Thank you to Air New Zealand for moving the birds between islands for no cost. Thank you to Kiwis for Kiwi for supporting the monitoring component of this work. Thank you to the Kakapo Team for assisting us while monitoring the kiwi on Anchor Island. Thanks to Hugh Robertson and Rogan Colbourne for their hard work catching kiwi on Kapiti Island, Gen Spargo for assistance on Kapiti, Hohepa Potini for accompanying the birds from Kapiti Island, Dave Taylor for welcoming them to Anchor Island, and Jane Tansell, Em Oyston, Chris Birmingham, and Pete McMurtrie for transmitter attachment on transfer day. Thanks to Jane Tansell and Sanjay Thakur for help with monitoring kiwi. Thanks to Marty Genet, Daryl Olsen and John Wilks for transmitter technology.

Appendix 1

Locations of little-spotted kiwi caught on Anchor Island January 2016: Locations map (JPG, 200K)