Division of Environment and Conservation Ministry of Natural Resources and Environment Managing myna birds (Acridotheres fuscus and A. tristis) in the Independent State of Samoa August, 2015 A plan prepared as one of the Management outputs of the GEF PAS project “Prevention, eradication and control of invasive alien species in the Pacific islands", funded by the Global Environment Facility (GEF), implemented by the United Nations Environment Programme (UNEP) and executed by Secretariat of the Pacific Regional Environment Programme (SPREP) in partnership with the Ministry of Natural Resources and Environment (MNRE). Prepared by: William G Nagle & Associates Environment, Education, Land Use Approved by: PO Box 15, CLYDE 9341, New Zealand Samoa National Invasive Task Team (SNITT) CONTENTS SUMMARY ......................................................................................................................... 1 1. Introduction ...................................................................................................................... 3 1.1 Species description ......................................................................................................... 3 1.2 Significance ................................................................................................................... 4 1.3 Status ............................................................................................................................. 4 2. Management Strategies, Goals and Options ...................................................................... 4 2.1 Past Distribution of mynas in Samoa .............................................................................. 4 2.2 Present Distribution of mynas in Samoa ......................................................................... 5 2.3 Population Trends of mynas in Samoa ............................................................................ 6 3. Current management efforts ............................................................................................. 7 4. Issues to consider concerning current management efforts ................................................ 8 5. Long-term goals ............................................................................................................... 9 5.1 Savai`i: eradication of myna species ............................................................................. 10 5.2 Upolu: long-term control .............................................................................................. 10 5.3 Biosecurity ................................................................................................................... 11 6. Options for management ................................................................................................ 11 6.1. Initial knockdown ........................................................................................................ 11 6.2 Follow-up ..................................................................................................................... 11 6.3 Ongoing disruption of myna behaviour ......................................................................... 11 7. Monitoring ..................................................................................................................... 13 8. Objectives and Workplan for 2015-17 ............................................................................ 13 CONCLUSIONS................................................................................................................ 15 ACKNOWLEDGEMENTS................................................................................................ 15 ANNEX 1: Myna Management Workshop ANNEX 2: Transect survey, May 2015 SUMMARY This document builds on lessons learned from 10 years of DEC-MNRE action on the myna issue, training workshops on invasive species management, a 2015 myna population transect survey (conservative estimate of total population in Samoa between 129,407 and 188,583 birds), appropriate literature and experiences in Pacific and other countries. Recommendations are made on strategies and the priority information needed to implement those strategies. Reducing the threat to the people and biodiversity of Malo Sa'oloto Tuto'atasi o Sāmoa from an ever-increasing population of myna (also mynah) birds (Maina fanua - Jungle myna (Acridotheres fuscus) and Maina vao – Common (also Indian) myna (Acridotheres tristis) will require implementation of all three strategies of invasive species management; prevention, eradication, control. The success of these strategies will depend on the collection of essential information, the allocation of sufficient resources, the application of a range of treatment methods and the active participation of village communities. At least 1,775 to 2,580 mynas will need to be removed every week for one year just to stop the population increasing from current numbers. Currently, the control method is application of toxic bait (DRC-1339 on buttered bread) along roadsides in response to villagers’ complaints about mynas. This is not proving successful in reducing the myna population and may result in tolerance or resistance to the toxicant. It is also a danger to non-target species which feed alongside mynas. For the future, eradication is the strategy that should be chosen for both the common myna and jungle myna on Savai`i. The myna population there (19,214 – 38,716 birds) is lower than on Upolu, the birds are still dispersing, the human population is low and communities want to be actively involved. Jungle mynas are the most common of the two species and they seem to be easier to trap. A period of pre-feeding followed by toxic baiting will achieve initial knockdown. Reducing habitat suitability, reducing available food sources, nest and egg identification and destruction, roost site identification and disruption, trapping and shooting can be used to complete the project. Further work is required on trapping methods; especially use of large walk-in traps. Adequate resourcing and logistical support will be essential for this effort as will the ability to carry out operations on both public and private property. To reduce costs and facilitate logistics, training for the eradication tasks could take place at a selected village on Upolu where a community wants to be actively involved. Reinvasion from Upolu to Savai`i can be addressed by effective biosecurity. Measures will be necessary to prevent mynas leaving from Upolu on any form of public or private transport and landing on Savai`i and to ensure mynas do not use the motu of Manono, Apolima and Nu'ulopa in the Apolima Strait as resting areas in any flight from Upolu to Savai`i. Ongoing control measures at the western end of Upolu, and the port areas in particular, will be necessary to keep myna numbers down and reduce the pressure to leave for new territory. Myna Management Plan, August 2015 1 The transect survey in May 2015 provided a combined estimate for Upolu of between 110,193 and 149,867 birds of both common myna and jungle myna, a very formidable number. Jungle myna is by far the most numerous of the two myna species on Upolu, 90,390 to 119,530, compared to 15,755 to 30,979 common myna. Upolu has about four times as many mynas as Savai`i and they are more widely dispersed, as is the human population which is about three times greater than Savai`i. A long-term control operation may succeed in reducing the myna population if more birds can be culled than are fledged each year. But there are no reliable data on which to base an estimate of the rate of population increase of each myna species in Samoa and to use in calculating a culling rate. Very little is certain knowledge in this project. Apart from lack of breeding and roosting information, insufficient rigorous work has been done on the interaction between common myna and jungle myna; although anecdotes abound. Jungle myna is reputed to always be first to take bait and to enter traps, while common mynas observe the outcome before taking any action. A reduction in numbers of jungle mynas may result in an increase in the common myna population as they take over jungle myna habitat. It is concluded that eradicating mynas on Savai`i and undertaking long-term control of mynas on Upolu are strategies for managing these invasive birds in Samoa. The resources required for these projects will be significant in both monetary and labour terms. Careful planning and attention to detail will lead to successful projects, but only if the village and communities of Samoa are actively involved in the work. The next steps will involve finalising a long-term workplan to fill in as many information gaps as possible, developing an operational plan for the work on Savai`i and Upolu and seeking funding for those operations. Myna Management Plan, August 2015 2 1. Introduction Myna (also Mynah) birds (Acridotheres spp., Sturnidae (Starling family)) have been targeted for management in Malo Sa'oloto Tuto'atasi o Sāmoa since 2004. They were recognised as a problem on oceanic islands about 250 years ago1 and have become a nuisance at best and a serious pest at worst in several Pacific Island Countries and Territories2. The Government of Samoa has expressed the desire to remove myna birds from the country and has provided money to work towards that goal. The Global Environment Facility Pacific Alliance for Sustainability (GEF-PAS) Invasive Alien Species project funded by the United Nations Environment Program and executed