View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Lincoln University Research Archive 107 Notornis, 2013, Vol. 60: 107-114 0029-4470 © The Ornithological Society of New Zealand, Inc. Translocations of North Island kokako, 1981-2011 JOHN INNES* Landcare Research, Private Bag 3127, Waikato Mail Centre, Hamilton 3240, New Zealand LAURA E. MOLLES Bio-Protection and Ecology Division, P.O Box 84, Lincoln University, Lincoln 7647, New Zealand HAZEL SPEED Department of Conservation, Auckland Area Office, P.O. Box 32026, Devonport, North Shore 0744, New Zealand Abstract The North Island kokako (Callaeas wilsoni) is a threatened endemic passerine whose distribution has declined greatly on the New Zealand mainland due primarily to predation by ship rats (Rattus rattus) and brushtail possums (Trichosurus vulpecula). It persists in 21 populations, of which 10 (48%) have been established by translocation, and 1 has been supplemented by translocation. Of the 11 populations subject to translocation, 4 are on islands and the remainder are on the mainland; 7 translocations have resulted in successful new or supplemented populations and another 4 translocations are in progress. Translocations to another 5 sites did not establish breeding populations for various reasons. In total, there were 94 translocations of 286 kokako to the 16 sites, and the number released at a site averaged 18 (range 3-33) birds. Kokako were released at a site over an average period of 49 months (range 1-159 months) with a mean of 3 birds (maximum 10) released per day. The small numbers of kokako released and the long time required to complete a translocation were due to the difficulty and high expense of catching kokako. Translocations will continue to be important for the conservation of this species, to establish further new populations and to limit inbreeding depression and allele loss in existing populations. Innes, J.; Molles, L.E.; Speed, H. 2013. Translocations of North Island kokako, 1981-2011. Notornis 60(1): 107-114. Keywords New Zealand birds; translocation; conservation; ecological restoration INTRODUCTION of habitat clearance, the key cause of current North Island kokako (Callaeidae: Callaeas wilsoni) decline and limitation is predation of eggs and is an endemic New Zealand passerine classified as chicks and occasionally adult females by ship rats ‘endangered’ by Birdlife International but recently (Rattus rattus) and brushtail possums (Trichosurus downgraded from ‘nationally endangered’ to vulpecula; Innes et al. 1999). The recently improved ‘nationally vulnerable’ in New Zealand (Miskelly conservation status of the kokako was due to et al. 2008). Although the historical decline in effective and sustained predator control combined kokako distribution was primarily the result with translocation to new sites, some of which were predator-free offshore islands. In 1999, only ca. 330 pairs of North Island kokako Received 8 Jul 2012; accepted 5 Mar 2012 remained in 13 relict populations and a further *Correspondence: [email protected] 70 pairs existed on 2 islands to which kokako had 108 Innes et al. been translocated in the previous decade. By 2010, Centre and other captive facilities, and 20 were the number had almost doubled to ca. 780 pairs captured from Tiritiri Matangi I to assist with the in 21 populations, of which 10 (48%) populations management of perceived inbreeding depression were established and 1 had been supplemented by there. translocation. The current goal of kokako recovery planning is to reach 1000 pairs by 2016, in sustainable Objectives and outcomes forest communities throughout the North I. The earliest releases of kokako to Little Barrier With the exception of 12 birds sourced from (Hauturu) and Kapiti Is were undertaken partly to captivity, all translocated kokako have been rescue birds threatened on the mainland by felling captured from the wild by attracting them with of native forests, primarily in the Bay of Plenty, and playback into mist-nets set in gaps within their partly to establish safe populations on pest-free forest habitat. Birds were then either transferred to islands as had been done successfully with other the new site immediately or held in temporary tent threatened bird species previously (Atkinson 2001; or permanently constructed aviaries for up to 10 Innes et al. 2010). Consequently these sites received days. The holding of birds was partly to aggregate many translocations of very small numbers of birds kokako until enough had been caught, when all over many years. However, research on declining were moved together, and partly to hold birds mainland populations during the 1990s revealed while disease screening was carried out and results substantial male excess due to high female mortality returned prior to release. Capture and transfer and poor nesting success in mainland populations techniques are described in detail in Flux and Innes (Innes et al. 1999; Flux et al. 2006), so in retrospect it (2001) and one account is also described in Marsh was clear that few females and few young birds had (1995). been put on these islands (Brown et al. 2004). The purpose of this paper is to document all From ca. 1996 onwards, most translocations kokako translocations undertaken during the of kokako were intended to establish new wild period from 1981-2011, briefly describing source populations at large pest-managed sites and a few and destination sites, translocation objectives key healthy mainland populations were harvested and outcomes, and factors that have influenced for this purpose. These birds were frequently translocation success. It expands and updates the young, with equal numbers of females and males, brief review in the Appendix of Molles et al. (2008). and sometimes they could be caught in larger numbers, with up to 10 being released in a day. METHODS Translocations to these sites – at Pukaha, Boundary We surveyed all available literature, mostly Stream, Ngapukeariki, Secretary I, Waitakere unpublished reports to the former New Zealand Ranges, Whirinaki and Otanewainuku – averaged Wildlife Service, the current Department of 20 kokako and only 5 releases each. Further releases Conservation (DOC), and to annual meetings of to these sites are likely, to maintain genetic diversity the North Island Kokako Recovery Group. We also and limit inbreeding. contacted key people within DOC and at managed Releases at 3 sites (Hunua Ranges, Pikiariki and sites to check facts and to resolve uncertainties. Puketi) were intended to supplement small remnant populations and speed population recovery. This was successful in the Hunua Ranges (Overdyck 1999; RESULTS HS, unpub. data) after 4 releases and where original Excluding translocations to captive breeding resident kokako were moderately abundant, but facilities, from 1981 to 2011 there were 94 not at the other sites that had single releases and translocations involving a total of 286 kokako to where few resident kokako remained. 16 sites (Appendix 1). The total number of kokako Five kokako were placed on Lady Alice I released at a site averaged 18 (range 3-33) birds. (Northland) in an attempt to get offspring from They were released at a site over an average period one of the last remaining Puketi Forest kokako that of 49 months (range 1-159 months) with a mean was at the time perceived to have unique genetic of 3 birds (maximum 10) released per day. Most material, but this was unsuccessful and in 2010 kokako were captured and removed from the the Kokako Recovery Group recommended that largest managed remaining populations, including remaining birds be removed and released in Puketi 59 birds from Te Urewera National Park, 46 birds Forest along with others from nearby Mataraua from Mapara, 27 birds from Kaharoa, 25 birds from Forest to establish a population in situ. Seven male Rotoehu, and 15 birds from Waipapa. These are all kokako were translocated to Mokoia I (135 ha) in forested, publically owned sites in the central North Lake Rotorua in Jun 2006 to allow tourists to see Island of New Zealand, administered by the New and hear the birds while removing the possibility of Zealand Department of Conservation. A further 25 breeding. The release of males only was a political birds were sourced via Mt Bruce National Wildlife compromise after the Kokako Recovery Group Translocations of kokako 109 objected to establishing a breeding population on Marlborough Forest, despite the possible anchoring such a small island. Finally, kokako were placed presence of 1 previously released male in Trounson on Tiritiri Matangi I starting in 1997 to attempt to (Gillies et al. 2003). preserve genetic material from Taranaki, where In 1997, a juvenile male and 2 female kokako the species is now extinct. The intention was that (1 adult and 1 juvenile) were translocated from a population of kokako with Taranaki genes would Mapara to Pikiariki Ecological Area, Pureora. The build up on Tiritiri Matangi I and then some adult female moved widely in Pikiariki before the individuals would be returned to a suitable pest- transmitter signal ended after 42 days, and the bird managed area in Taranaki. However, no suitable was not seen again. Both juveniles travelled to and site has yet been prepared in Taranaki, and ongoing from the large adjacent Waipapa Ecological Area management to limit breeding between closely for 6-9 months, and were last sighted in shrubland related individuals has been required on Tiritiri adjacent to Pikiariki in May 1998. Matangi I. Nonetheless, the presence of kokako Founder kokako released to 196 ha Tiritiri on Tiritiri Matangi I, which receives 35,000 visitors Matangi I in Aug 1997 ranged widely (up to 2.2 km annually, has probably yielded advocacy benefit. between monthly fixes) for 3 months before settling Overall, translocations have successfully into territories. Four males released 7 months later established new populations at 6 sites (Little Barrier, moved less and finally settled near the other birds Kapiti and Tiritiri Matangi Is, Pukaha (Mt Bruce), (Jones 2000).