SPREP Library Cataloguing-in-Publication Data Report on a visit to Niuafo’ou Island, Kingdom of Tonga : the Polynesian Megapode Megapodius pritchardii, monitoring and conservation of Malau on Niuafo’ou Island. Apia, Samoa : SPREP, 2019. 38 p. 29 cm. ISBN: 978-982-04-0692-6 (print) 978-982-04-693-3 (ecopy) 1. Polynesian megapode – Bird survey – Niuafo’ou Island – Tonga. 2. Tongan megapode – Monitoring & conservation – Tonga. 3. Malau – Endangered bird species – Tonga – Oceania. I. Pacific Regional Environment Programme (SPREP). II. Title 591.529 PO Box 240, Apia, Samoa +685 21929 [email protected] www.sprep.org Our vision: A resilient Pacific environment sustaining our livelihoods and natural heritage in harmony with our cultures. Report on a visit to Niuafo’ou Island, Kingdom of Tonga The Polynesian Megapode Megapodius pritchardii, monitoring and conservation of Malau on Niuafo’ou Island Dr David J. Butler INDEX Executive Summary 2 1. INTRODUCTION 3 2. SURVEY SCHEDULE AND METHODOLOGY 4 2.1 Schedule 4 2.2 Methodology 5 3. RESULTS 6 3.1 Nesting Ground activity 6 3.2 Nest camera results at active burrows 8 3.3 Numbers of birds recorded 9 3.4 Areas occupied by malau 10 3.5 Other native fauna and invasive species 10 3.6 Education programme 10 3.7 Community awareness programme 11 4. DISCUSSION 12 4.1 Comparison with previous surveys 12 4.1.1 No. of nesting grounds active 12 4.1.2 Numbers of active and inactive burrows at nesting grounds 13 4.1.3 Numbers of birds recorded 15 4.1.4 Areas occupied by malau 16 4.2 Assessment of threats 16 4.2.1 Egg collecting 16 4.2.2 Mammals including feral animals 17 4.2.3 Other invasive species 17 4.2.4 Loss or alteration of habitat 17 5. CONCLUSIONS 18 6. RECOMMENDATIONS 19 Acknowledgments 20 References 21 Annex 1: Observations of other native fauna and invasive species 22 1 Integrated Island Biodiversity Technical Series EXECUTIVE SUMMARY Field surveys for the Polynesian megapode (malau) were carried out from 4-12th November, visiting all nesting grounds and assessing numbers and distribution using playback of calls. Nine nesting grounds were found to be active, a number that has remained relatively stable since the 1990s. However the numbers of active burrows within nesting grounds has declined significantly at most sites since the 1990s. At four compact sites where all burrows would have been located during this survey, three showed declines of 72-96% and one showed a slight increase. This decline in active burrows indicates a significant decline in malau numbers in many areas. Nesting ground results during the last three surveys of 2010, 2012 and this one are broadly similar. Earlier conclusions, that the 2010 survey had documented an alarming decline and that the 2012 had shown a recovery over a two-year period, are not borne out by re-analysis. Fewer malau were located using playback than in the 2012 survey. However conditions were very dry with seedlings wilting in the forest, and birds were considered to be less responsive to playback as they were likely to be under pressure to find enough food. Over-harvesting of eggs was considered by Göth & Vogel (1995) to be the main reason for the historic decline in malau and it seems most likely to have been the cause of the further decline since their study of the 1990s. However egg collecting appears to be dying out as a tradition and this may have led to the population stabilising at low levels since 2010. The survival of the malau population on Niuafo’ou seems assured unless new threats arise through volcanic events, the arrival of new invasive species (e.g. ship rats or mongoose), or marked changes in land use that see increased forest clearance. Integrated Island Biodiversity Technical Series 2 1. INTRODUCTION The objective of the project was improved conservation status of priority threatened species, consistent with selected outcomes set out in the Island Biodiversity Programme of Work (IBPOW). Surveys were initially aimed at establishing the status of species on three different islands Niuafo’ou, Late and Fonualei to assess fate of introduced populations of Polynesian Megapode. Surveys of Late and Fonualei were conducted in September 2013 but the cancellation of flights to Niuafo’ou that year resulted in surveys there being delayed until the current survey a year later. The main focus of the survey on Niuafo’ou was defining the status of the malau or Polynesian megapode (Megapodius pritchardii). The author’s consultancy role included working closely with IIB Project Coordinator to facilitate the survey, developing methodologies, expected outcomes and key deliverables, and acting as Activity Team Leader. Niuafo’ou Island is the most northerly island in the Kingdom of Tonga and with the two islands of Niuatoputapu and Tafahi 200km to the east forms the Niua Group. It is the summit of a largely submerged basaltic shield volcano situated at 15o36‘S 175o38W, covering an area of 15km2, 8-km wide with a 5km wide caldera largely filled by a lake containing several islands. The island has been subject to periodic volcanic eruptions, the most recent major one in 1946 which led to the evacuation of people from the island. A proportion returned in 1958 and a largely number remained on Eua Island where the Government provided for their settlement. The most recent census (2011) recorded a population of 523 in 114 households (Statistics Department 2011) representing a significant 19% population decline from 646 in 139 households in 2006. Much of the island is covered in forest, relatively unmodified inside the caldera and more secondary forest outside representing past clearance for plantations. The more recent lava flows are largely bare rock or covered in fern scrub and ironwood trees (Casuarina littorea). Small areas are currently occupied by villages and plantations. The malau or Polynesian megapode was only found on Niuafo’ou until a second population was estanlished relatively recently on Fonualei Island in the Vava’u Group. Like some other megapodes it uses volcanic heat to incubate its eggs, burying them up to 1.7m deep on a small number of nestiong grounds, mostly located in the caldera near the crater lake. It has been the subject of several studies, the most comprehensive being that of Ann Göth and Uwe Vogel over 1991-93 (e.g. Göth & Vogel 1995). Two surveys have been carried out recently, in 2010 and 2012, with significantly different findings. The current survey was designed to use similar techniques. 3 Integrated Island Biodiversity Technical Series 2. SURVEY SCHEDULE AND METHODOLOGY The survey team consisted of Dr Butler and three staff of the Department of Environment and Climate Change: Samuelu Pakileata, Senituli Finau and Saia Fonokalafi, supported by IIB Project Coordinator Ana Fekau in Nuku’alofa. Fieldwork was conducted on Niuafo’ou between 4th and 12th from a base in the village of Esia. 2.1 Schedule 1-2nd September – Meetings and preparation in Nuku’alofa 3rd September – Flights to Niuafo’ou via Vava’u. Briefing meeting with Viliami Falevai, Acting Government Representative, Niuafo’ou. 4th September Surveyed nesting grounds Utumea, Utupalapu, and searched area with grid ref. for Lolo 1 without success with Lafaele Pe’ei. 5th September Surveyed nesting grounds Teleka, Loloola and Vaikona on shores of main lake with Lafaele Pe’ei by boat. 6th September Searched area with grid ref. for Kele’efu’efu without success; surveyed of Akofa by boat, with Lafaele Pe’ei. 8th September Surveyed nesting ground of Kele’efu’efu with Viliami Filiai and Lafaele Pe’ei. 9th September Walked track to Hikutemotu with playback, landed on Motu Molemole and set up camera on burrow, surveyed Koko and Motu Lahi, returned to overnight on Motu Molemole, with Lafaele Pe’ei. 10th September Departed from Motu Molemole; surveyed Motu Late, Vai Ahau, walked back to Esia from Hikutemotu, with Lafaele Pe’ei. 11th September Surveyed Lolo 2 and 3 with Lafaele Pe’ei. 12th September Preparation of presentations for awareness programmes. DB visited area north of Hikutemotu to photograph malau. 15th September Delivered awareness programmes at Sapa’ata Primary School in Kolofo’ou village and High School in Sapa’ata and held a community workshop there in evening. 16th September Delivered awareness programmes at Primary School in Tongamama’o village and held a community workshop at Petani village in evening. Surveyed slopes above main lake part of way between Koko and Hikutemotu. 17th September In Esia waiting for flight to Vava’u – postponed several times then cancelled. 18th September Flew to Vava’u and Nuku’alofa. Integrated Island Biodiversity Technical Series 4 2.2 Methodology When surveying nesting grounds we located sites using GPS readings from 2012 survey and the guidance of egg collectors Lafaele Pe’ei and Viliami Filiai. Searches were made in the vicinity to locate and map (with GPS readings) all the burrows present and typically at least one was dug up to obtain a temperature and prove activity (by finding eggs, chicks or egg fragments. All sightings or calls of malau were recorded. Temperatures were recorded using a digital thermometer that obtained readings from the surface and from a probe with a 3-m wire placed at the base of a burrow in a small polythene bag. Reconyx PC900 Hyperfire Professional IR cameras which take still pictures when triggered by any movements were set up on nest burrows at Utupalapu (11 days/nights) and Mote Molemole (1 day/ night). Figure 1. Senituli Finau (left) and Lafaele Pe’ei digging out a nesting burrow Malau calls were played back at each nesting ground to determine if birds were in the vicinity, and played at regular intervals on walking transects behind Vaikona and on the track to Hikutemotu, and irregularly at other locations to try to determine which habitats birds were using.