REDONDA RESTORATION PROGRAMME: Technical report on the final check following the eradication of black rats (Rattus rattus) from , & , June‐July 2018

Cover illustration: Magnificent frigatebirds, Fregata magnificens, on their nest sites on Redonda (Photo: Elizabeth Bell, WMIL).

THE OPINIONS OF THE AUTHORS DO NOT NECESSARILY REFLECT THE OPINIONS OF THE PARTNER ORGANISATIONS OF THE REDONDA RESTORATION PROGRAMME.

PUBLISHED BY: Redonda Restoration Programme, St. John’s, Antigua

RECOMMENDED CITATION: Bell, E.A. & Challenger, S. (2018) Technical report on the final check following the eradication of black rats Rattus rattus from Redonda, , June‐July 2018. Report from Wildlife Management International Ltd and Fauna & Flora International to the Redonda Restoration Programme, St John’s, Antigua and Barbuda.

Author details: Ms. Elizabeth ‘Biz’ Bell Ms. Shanna Challenger Senior Ecologist Redonda Restoration Programme Coordinator Wildlife Management International Ltd Department of Environment/Environmental PO Box 607, Awareness Group/Fauna & Flora International Blenheim 7240 St John’s New Zealand Antigua www.wmil.co.nz Email: shanna.challenger@fauna‐flora.org Email: [email protected]

All photographs in this report are copyright ©WMIL unless otherwise credited, in which case the person or organization credited is the copyright holder.

The Redonda Restoration Programme was launched in 2016 by the Government of Antigua and Barbuda, Environmental Awareness Group, British Mountaineering Council, Fauna & Flora International, Island Conservation and Wildlife Management International Ltd. This partnership is working to rehabilitate Redonda into a healthy island ecosystem that is sustainably managed for the conservation of indigenous biodiversity, and to preserve Redonda’s important historical values and facilitate the sustainable use and enjoyment of Redonda by present and future generations. The development of this plan was funded by the National Fish and Wildlife Foundation and Darwin Initiative (#23‐003: Eradicating Invasive Species from the Highest Priority Island).

EXECUTIVE SUMMARY 1. Redonda has been internationally recognised as an Important Bird Area and supports rare and unique and plants of both national and global importance, including seabirds such as magnificent frigatebird Fregata magnificens, masked booby Sula dactylatra, red‐ footed booby S. sula and brown booby S. leucogaster, as well as smaller numbers of red‐ billed tropic bird Phaethon aethereus, brown noddy Anous stolidus and bridled tern Sterna anaethetus and endemic such as the Redonda ground lizard Philodoscelis atrata and Redonda tree lizard Anolis nubilus and an unnamed dwarf gecko (Sphaerodactylus sp.). 2. The Redonda Restoration Programme (RRP) is a collaborative programme of the Government of Antigua & Barbuda, Environmental Awareness Group (EAG), Fauna & Flora International (FFI), British Mountaineering Council (BMC), Wildlife Management International Ltd (WMIL) and Island Conservation (IC), with support from Darwin Initiative through UK Government funding, National Fish & Wildlife Foundation, Taurus Foundation, Global Wildlife Conservation, Syngenta Crop Protection AG and Caribbean Helicopters Ltd. 3. This partnership is working to rehabilitate Redonda into a healthy island ecosystem that is sustainably managed for the conservation of indigenous biodiversity, and to preserve Redonda’s important historical values and facilitate the sustainable use and enjoyment of Redonda by present and future generations. 4. Redonda had a large population of invasive alien black rats (Rattus rattus). Together with feral goats (Capra hircus, which were relocated in 2018), these rodents were heavily implicated in the severe and ongoing decline of the island’s vegetation and native wildlife populations, and a number of species have become extinct. The once‐forested island had reached advanced stages of desertification. 5. The eradication of black rats from Redonda was completed between 13 February and 7 April 2017 using a combination of ground‐based bait station and aerial methods was led by island restoration specialists from Wildlife Management International Ltd with a team of nine volunteers over the ten‐week project. 6. Long‐term monitoring was carried out between April 2017 and May 2018 by RRP personnel. 7. The final check was carried out by Wildlife Management International Ltd. personnel and RRP staff and volunteers. 8. Monitoring during the final check consisted of flavoured wax (peanut, chocolate and aniseed), tracking tunnels and trail cameras in a combination of closed lockable biosecurity stations and points in the open over the island (n = 169 stations, excluding biosecurity stations). 9. There were between 1 and 5 complete checks (depending on the areas, i.e. coastline, cliff scramble or top) done over 18 days. 10. Rats were not detected on any monitoring station or at any location on Redonda. 11. Redonda was declared rat‐free on 31 July 2018. 12. Ongoing monitoring of the 39 biosecurity stations on the island will continue indefinitely as part of the biosecurity requirements to maintain the rodent‐free status of Redonda. These biosecurity requirements will be the responsibility of the RRP personnel with support from Fauna & Flora International and other trained personnel when visiting the island.

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13. RRP, EAG and Department of Environment (DOE) staff and volunteers were trained in safe rodenticide use, long‐term monitoring, biosecurity and rodent detection techniques. 14. Research and monitoring of the seabirds, land birds, reptiles and vegetation will continue after the eradication programme to assess the effects of removing rats on the Redonda ecosystem. RRP, EAG and DOE staff and volunteers and other researchers will undertake this work with technical support from Fauna & Flora International. 15. The operation on Redonda has shown that a well‐planned, adequately resourced, well‐ executed programme, with the complete support of partner agencies and other stakeholders and led by an experienced operator with dedicated volunteers means total eradication of rats is possible on islands with difficult access and very steep terrain. 16. The eradication of black rats from Redonda is a major achievement and will provide the opportunity to restore and enhance the , bird and other native species communities of the island.

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TABLE OF CONTENTS EXECUTIVE SUMMARY i TABLE OF CONTENTS iii ACKNOWLEDGEMENTS iv TECHNICAL REPORT OF THE FINAL CHECK FOLLOWING THE ERADICATION OF BLACK RATS (RATTUS RATTUS) FROM REDONDA, ANTIGUA & BARBUDA 1 1 INTRODUCTION 1 1.1 REDONDA 2 2 GOAL AND OBJECTIVE OF REDONDA RAT ERADICATION 5 3 METHODS 5 4 RESULTS 9 4.1 OTHER OBSERVATIONS DURING THE FINAL CHECK ON REDONDA 11 4.1.1 LIZARD OBSERVATIONS 11 4.1.2 BIRD OBSERVATIONS 11 4.1.3 VEGETATION OBSERVATIONS 12 4.1.4 GOAT OBSERVATIONS Error! Bookmark not defin 5 CONCLUSIONS 13 6 RECOMMENDATIONS 14 7 REFERENCES 14 8 APPENDICES 18 8.1 TIMETABLE OF ACTIVITIES FOR THE REDONDA FINAL CHECK (14 JUNE TO 2 JULY 2018) 18

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ACKNOWLEDGEMENTS This work was carried out under the auspices of the Redonda Restoration Programme (RRP), a collaborative programme of the Government of Antigua and Barbuda, Environmental Awareness Group (EAG), British Mountaineering Council (BMC), Fauna & Flora International (FFI), Island Conservation and Wildlife Management International Ltd (WMIL). This programme was launched in 2016 with funding from Darwin Initiative through UK Government funding (grant #23‐003), National Fish & Wildlife Foundation, Global Wildlife Conservation, Taurus Foundation, Betty Liebert Trust, Waitt Foundation and additional technical and material support from Caribbean Helicopters, Syngenta Crop Protection AG and Bell Laboratories Inc. Additional staff time, international flights and equipment were provided by Fauna & Flora International (FFI) and Wildlife Management International Ltd. The authors would like to thank to the following people and organisations: The Government of Antigua and Barbuda—in particular the Ministry of Health, Wellness and the Environment and the Veterinary and Livestock Division under the Ministry of Agriculture, Fisheries and Barbuda Affairs—for their kind permission to conduct field work and for their interest, support, advice and in‐kind assistance throughout the development of this component of the RRP. Salina Janzan, Adam Long and Waldo Etherington, for their hard work during the Final Check phase. Jack Ibbotson, Chris Clarke, Thea Eldred, James Stops, Salina Janzan, Silas Walton, Bede West, John Tayton and Edward Marshall for their hard work, enthusiasm and support during the rat eradication phase; the success of the project so far, and in the future, is a credit to them. Carolyn Thomas, for her help with plant identification and assistance in the field when on Redonda. Sophia Steele, FFI Eastern Caribbean Coordinator, for her assistance with the logistical arrangements on Antigua, assistance in the field and ongoing support of the project. Jenny Daltry, FFI, Senior Conservation Biologist, for her assistance with all phases of the Redonda Restoration Programme, review of this report and continuing advice for the project. Natalya Lawrence, Coordinator, Offshore Islands Conservation Programme, EAG, for her support of the project. The team at Caribbean Helicopters for their ongoing support of the project. We also thank other individuals for peer‐reviewing this plan.

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TECHNICAL REPORT OF THE FINAL CHECK FOLLOWING THE ERADICATION OF BLACK RATS (RATTUS RATTUS) FROM REDONDA, ANTIGUA & BARBUDA 1 INTRODUCTION Redonda has been internationally recognised as an Important Bird Area and supports rare and unique animals and plants of both national and global importance, including seabirds such as magnificent frigatebird Fregata magnificens, masked booby Sula dactylatra, red‐footed booby S. sula and brown booby S. leucogaster, as well as smaller numbers of red‐billed tropic bird Phaethon aethereus, brown noddy Anous stolidus and bridled tern Sterna anaethetus and endemic reptiles such as the Redonda ground lizard Pholidoscelis atrata and Redonda tree lizard Anolis nubilus and an unnamed dwarf gecko (Sphaerodactylus sp.) (Morse, 1979; Malhotra & Thorpe, 1999; Office of the Prime Minister, 2001; Daltry, 2007; Prosper et al., 2008; Sylvester et al., 2009; Devine et al., 2010; BirdLife International, 2012; Bell & Daltry, 2012; Hedges & Conn, 2012; Lowrie et al., 2012). Black rats are one of the most widespread and devastating invasive species around the world and are recorded on 80% of the world’s islands (Moors & Atkinson, 1984; Atkinson, 1985; Jones et al., 2008; Bell, et al., 2016). Rats have been successfully removed from islands ranging in size from 1 to 36,000 ha throughout the world including a number of islands throughout the Caribbean region and over 15 in Antigua itself (Day & Daltry, 1996; Daltry, 2000; Varnham & Daltry, 2006; Howald, et al., 2007; Witmer, et al., 2007; Varnham, 2010; Bell, 2012; Lawrence, et al., 2013; Havery et al., 2014; Parks & Wildlife Service, 2014; Lawrence & Daltry, 2015; Martin & Richardson, 2017). The Redonda Restoration Programme (RRP) is a collaborative programme of the Government of Antigua & Barbuda, Environmental Awareness Group (EAG), Fauna & Flora International (FFI), British Mountaineering Council (BMC), Wildlife Management International Ltd (WMIL) and Island Conservation (IC), with support from Darwin Initiative through UK Government funding, National Fish & Wildlife Foundation, Taurus Foundation, Global Wildlife Conservation, Betty Liebert Trust, Waitt Foundation and additional technical and material support from Caribbean Helicopters, Syngenta Crop Protection AG and Bell Laboratories Inc. This partnership is working to rehabilitate Redonda into a healthy island ecosystem that is sustainably managed for the conservation of indigenous biodiversity, and to preserve Redonda’s important historical values and facilitate the sustainable use and enjoyment of Redonda by present and future generations. The detailed feasibility study was prepared in 2012 and showed that the eradication of rats from Redonda was feasible (Bell & Daltry, 2012), the Operational Plan was prepared in 2016 (Bell & Daltry, 2016) and the rat eradication was completed between February and April 2017 (Bell, et al., 2017). Ongoing monitoring for surviving or incurring rats and recovery of the reptiles, birds and other native species continued on Redonda between April 2016 and May 2018 by RRP.

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Wildlife Management International Ltd. was contracted to complete the final check on Redonda to confirm the complete eradication of black rats. This was carried out in June and July 2018. This report details all the aspects of the final monitoring check only. All other aspects of the feasibility study, rat eradication and on‐going monitoring projects are available in the relevant reports (Bell & Daltry, 2012; Bell & Daltry, 2017; Bell, et al., 2017) through RRP, FFI and WMIL.

1.1 REDONDA Redonda (53 ha1, 16°56’N; 62°21’W) is the third largest island in Antigua and Barbuda (Morse, 1979). It is situated 56 km southwest of Antigua, 22 km northwest of and 32 km southeast of (Figure 1). Redonda is uninhabited and is 1.6 km long, 0.5 km wide and rises to nearly 400 m with sheer cliffs around much of the island (Figure 2, Morse, 1979; Prosper, et al., 2008). Redonda is state‐owned (i.e. crown land). Buildings were constructed during the guano mining period (Morse, 1979; Prosper, et al., 2008), but most structures are in ruins, many of them damaged by hurricanes. There used to be an access route from the shore up a steep gully, but this was destroyed by a series of rock falls in March 2017 and remains inaccessible to date (Figure 2). Safe access is currently only possible by helicopter to several flat areas on the top of the island (Figure 2). Redonda has a tropical dry climate with low rainfall (<1,000 mm per year) with the wet season overlapping with hurricane season (August to November). There is limited vegetation; generally restricted to a few trees growing on steep cliff faces and a flush of green herbs after rain. There is no permanent source of freshwater, although there are several rainwater seepage points, including one in Centaur’s Cave. Around 70 species of plants have been recorded on Redonda over the past 70 years, but many have disappeared and at least 20 species are not native to the Caribbean (Howard, 1962; Pratt & Thomas, 2011). Historically Redonda was forested, but only a handful of woody plants remain, and much of the island has a barren appearance. Short‐leafed fig trees Ficus citrifolia can be found on the cliffs (Bell & Daltry, 2012; Lindsay & Horwith, 1997). With the loss of vegetation has come the loss of topsoil, and much of the island is seriously eroded and unstable. Much of Redonda is sparsely vegetated cliffs, talus/scree slopes and jumbled boulders (Devine, et al., 2010). Redonda has been designated an Important Bird Area (no. AG001) because it holds regionally significant populations of seabirds, specifically magnificent frigatebird, masked booby, red‐ footed booby and brown booby, as well as smaller numbers of red‐billed tropic bird, brown noddy and bridled tern (Prosper, et al., 2008; BirdLife International, 2012). Audubon’s shearwater Puffinus iherminieri was previously listed as present on the island (Sylvester, et al., 2009), and calls were heard in 2009 (Lowrie, et al., 2009) and twice during the eradication in 2017 (Bell, et al., 2017).

1 Published areas vary widely, with mistakes often repeated by subsequent authors. For example, Prosper, et al. (2008) give the area as being up to 260 hectares, while Horwith & Lindsay (1997) give the area as 500 hectares. However, at 1.6 km long and 0.5 km wide at its widest point, these higher figures are not credible. The planar area of 53 hectares was measured by Dr. Brian Cooper using GIS from the best available topographic map but should be verified using a geo‐rectified satellite image when available. The ‘three‐dimensional’ surface area is probably nearer 80 hectares owing to its steeply pointed shape, and is the estimate used in this report, but again should be verified.

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Figure 1 Location of Redonda, Antigua & Barbuda.

N

500 m

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Figure 2 Redonda, Antigua & Barbuda.

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There are very few records of land birds on the island; burrowing owl Athene cunicularia were recorded in the past (Clarke, 1957; Office of the Prime Minister, 2001), but are now locally extinct. Zenaida doves Zenaida aurita, peregrines Falco peregrinus, American kestrels Falco sparverius, Caribbean Eleania Elaenia martinica, Lesser Antillean bullfinch Loxigilla noctis, Pearly‐eyed thrashers Margarops fuscatus, barn swallows Hirundo rustica and bananaquits Coereba flaveola were observed in 2012 and 2017 (Bell & Daltry, 2012; Bell, et al., 2017). Redonda has six species of lizards, at least four of which are endemic to the island and all are threatened with extinction (Malhotra & Thorpe, 1999; Daltry, 2007; Prosper, et al., 2008; Bell & Daltry, 2012; Hedges & Conn, 2012). The Redonda ground lizard and Redonda tree lizard are the most conspicuous. No or tortoises have ever been recorded on Redonda. Green turtles Chelonia mydas and hawksbill turtles Eretmochelys imbricata are commonly seen in the waters around the island (Prosper, et al., 2008; Bell & Daltry, 2012). Although domestic sheep Ovis aries, dogs Canis lupus familiaris and cats Felis catus were on Redonda during the mining period (Morse, 1979), the only mammals still present on the island during the eradication operation were the non‐native feral goats and black rats (Morse, 1979; Lindsay, 2012). Bats (suspected to be Mexican free‐tailed bat Tadarida brasiliensis) were recorded on Redonda during the eradication in 2017 (Bell, et al., 2017). It is likely that black rats were accidentally introduced to Redonda sometime after the 17th century when rats were first recorded in the Caribbean region (Campbell, 1991; Long, 2003); probably when ships were wrecked along the shores. No house mice Mus musculus have ever been recorded on Redonda. 2 GOAL AND OBJECTIVE OF REDONDA RAT ERADICATION The goal of the operation to eradicate invasive alien rats in order to establish Redonda as a haven for native biodiversity and restore many of its natural ecological functions. The objective was to eradicate all black rats from Redonda while minimising any adverse impacts on the environment, non‐target species (including goats), archaeology and , for the conservation and restoration of the island’s nationally and globally important biodiversity. The objective of this final check was to confirm the success of the black rat eradication operation completed between 13 February and 7 April 2017. 3 METHODS The final monitoring check on Redonda took place from Thursday 14 June to Monday 2 July 2018. It was carried out by teams of two to five people (a combination of one WMIL staff member, between one and three RRP volunteers and one RRP staff member). A detailed timetable of activities is listed in Appendix 8.1. Monitoring lines were established during this final check phase: (i) on the top of the island using as close to the original bait station positions as possible, (ii) on three of the original cliff scramble routes, (iii) using the biosecurity stations, and (iv) on along the accessible section of coastline (Figure 3). All other areas were too hazardous to access.

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Figure 3 Location of the monitoring points (including biosecurity stations) used during the Final Check on Redonda, June/July 2018. Where • is monitoring point and • is a permanent biosecurity station.

Monitoring points were placed out at 30 m intervals along each line, except for the biosecurity stations which are 50 m apart (Figure 3). Each point was put into position before being individually numbered, mapped using GPS and was added into a GIS‐linked database. Flagging tape and spray paint was used to locate points (Figure 4).

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Flavoured wax (chocolate and aniseed) were placed at each monitoring point (Figure 4) and tracking tunnels and trail cameras placed in random locations (i.e. near good rat habitat or directly viewing monitoring points). The monitoring points were placed off the ground wherever possible to prevent hermit crabs from accessing the wax. Figure 4 Monitoring point on Redonda used during the Final Check, June‐July 2018. R‐L: Aniseed flavoured wax block in position on Redonda; spray paint and flagging tape marking monitoring point location.

Figure 5 Permanent biosecurity station on Redonda used during the Final Check, June‐July 2018.

The permanent biosecurity stations (using commercially available lockable bait stations) were placed on Redonda in April 2017 (Figure 5; Bell, et al., 2017). Regular checks of these stations had been carried out by RRP staff and volunteers between April 2017 and June 2018. Klerat® bait and chocolate‐flavoured resin blocks were put inside each biosecurity station and aniseed

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and chocolate flavoured wax was put on the outside of the biosecurity stations during the Final Check and checked as part of the monitoring lines. There was a total of 208 monitoring points on the islands including the permanent biosecurity stations; 39 biosecurity, 19 coastline, 110 island top and 40 cliff scrambles (Figure 3). A single flavoured wax block was placed along these monitoring lines; chocolate wax was used for three checks and then aniseed flavoured wax was added at each point (Table 1). Two flavours of wax (aniseed and chocolate) were placed at each cliff scramble and coastline monitoring station for every check (Table 1). Tracking tunnels and a trail camera were also placed out at selected ground monitoring points (Table 1). All the monitoring stations were checked every one to four days (weather and location dependent) (Table 1, Appendix 8.1). Any sign was recorded in waterproof field notebooks and added to the GIS‐linked database. Table 1 Date range and type of monitoring for each monitoring check on Redonda during the Final Check, June/July 2018. Where: Ch = chocolate flavoured wax, An = Aniseed flavoured wax, TT = tracking tunnel, Cm= camera. Biosecurity Top Cliff Scramble Check Coast N S & H AA A B C D A B 17/6/18 17/6/18 17/6/18 17/6/18 18/6/18 17/6/18 17/6/18 22/6/18 23/6/18 8/2/18 1 (Ch) (Ch) (Ch) (Ch) (Ch) (Ch) (Ch) (Ch) (Ch, TT) (Ch, An) 24/6/18 26/6/18 18/6/18 19/6/18 18/6/18 19/6/18 19/6/18 19/6/18 19/6/18 (Ch, An, (Ch, An, 2 (Ch) (Ch) (Ch) (Ch) (Ch) (Ch) (Ch) TT) TT) 27/6/18 28/6/18 20/6/18 22/6/18 21/6/18 21/6/18 21/6/18 22/6/18 22/6/18 (Ch, An, (Ch, An, 3 (Ch) (Ch) (Ch) (Ch) (Ch) (Ch) (Ch) TT, Cm) TT) 29/6/18 24/6/18 26/6/18 24/6/18 24/6/18 24/6/18 27/6/18 27/6/18 (Ch, An, 4 (Ch, TT) (Ch, TT) (Ch, TT) (Ch, TT) (Ch, TT) (Ch, TT) (Ch, TT) TT, Cm) 28/6/18 28/6/18 1/7/18 27/6/18 1/718 28/6/18 30/6/18 30/6/18 (Ch, An, (Ch, An, (Ch, An, 5 (Ch, An) (Ch, An) (Ch, An) (Ch, An) (Ch, An) TT) TT) TT, Cm) 29/6/18

6 (Ch, An) Areas of sand, mud or soil were checked to detect rat prints. All seabird nesting areas were checked for additional rat sign (e.g. predated or scavenged eggs, teethmarks on carcasses, etc.). Checking for active rat runs, chews or droppings was also completed along each of the monitoring routes. After the completion of the monitoring programme, all temporary monitoring stations were brought in from the field. The biosecurity stations remain in position and will continue to be checked by the RRP team and trained personnel when they visit Redonda. Currently there are four blocks of Klerat® bait and a single block of chocolate flavoured resin inside each biosecurity station and an aniseed and chocolate flavoured wax block on the outside of each station.

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4 RESULTS There were between 1 and 6 complete checks on 169 monitoring points and 39 biosecurity stations carried out during the Final Check on Redonda depending on the area (Table 1, Appendix 9.1). Rat sign was not recorded at any of the monitoring stations or biosecurity stations during any of the checks. No sign of rats (i.e. droppings, runs or chews) were recorded anywhere on Redonda over the same period. There was activity on the monitoring stations by non‐target species; insects (mainly ants and crickets), lizards and crabs interfered with the stations over 550 times over the entire Final Check (Table 2). Crabs, lizards and insects interfered with the most stations with crabs affecting over 70% of all stations (Table 2). Table 2 Number (and percentage) of monitoring stations affected by non‐target species and the weather on Redonda during the Final Check, June/July 2018. Non‐ Biosecurity Top Cliff Scramble Coast Total target N S & H AA A B C D A B (19) (208) species (22) (14) (6) (38) (24) (19) (29) (19) (21) 6 4 2 2 2 1 7 2 1 27 Ants (7.8%) (9.1%) (22.2%) (1.9%) (2.5%) (1.5%) (7.1%) (3.3%) (1.9%) (4.5%) 7 7 Crickets (6.7%) (1.2%) Insects 18 10 2 9 2 1 7 2 1 52

(all) (23.4%) (22.7%) (22.2%) (8.6%) (2.5%) (1.5%) (7.1%) (3.3%) (1.9%) (8.6%) 11 4 5 3 4 1 21 13 62 Lizard (14.3%) (9.1%) (4.8%) (3.8%) (61.5%) (1.0%) (35.0%) (25.0%) (10.2%) 7 48 28 7 88 74 60 91 27 8 438 Crab (46.7 (62.3%) (63.6%) (77.8%) (83.8%) (92.5%) (92.3%) (91.9%) (45.0%) (15.4%) (72.3%) %) 8 2 3 1 10 30 54 Melted (53.3 (4.5%) (2.9%) (1.3%) (16.7%) (57.7%) (8.9%) %) Total 77 44 9 105 80 65 99 60 52 15 606 The non‐target species affected different types of monitoring to different levels (Table 3); lizards interfered with tracking tunnels the most (Figure 6), crabs on flavoured wax, mainly chocolate (Figure 7) and insects have similar levels of interference on flavoured wax and on the Klerat™ bait inside the biosecurity stations. Table 3 Number of times a specific monitoring tool was affected by non‐target species on Redonda during the Final Check, June/July 2018. Non‐target Chocolate Aniseed Tracking Station Resin Total species wax wax tunnel Ants 15 (55.6%) 3 (11.1%) 1 (3.4%) 4 (14.8%) 4 (14.8%) 27 Crickets 7 (100%) 7 Insects (all) 22 (42.3%) 3 (5.8%) 1 (1.9%) 21 (40.4%) 5 (9.6%) 52 Lizard 21 (33.8%) 14 (22.6%) 27 (43.5%) 62 Crab 341 (77.9%) 73 (16.7%) 9 (2.1%) 11 (2.5%) 4 (0.9%) 438 Total 406 (69.3%) 93 (15.9%) 38 (6.5%) 36 (6.1%) 13 (2.2%) 586

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Figure 6 Ground lizard interference of tracking tunnels on Redonda during the Final Check, June/July 2018.

Figure 7 Crab interference on flavoured wax on Redonda during the Final Check, June/July 2018.

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Although crabs interfered with monitoring stations on the beaches and cliffs, most interference was recorded on the top of the island. Crabs interfered with almost all the monitoring stations at some point of the final check on Redonda. It is important to note that in some circumstances (n = 13), the monitoring point was simply missing (likely to have been taken by land or hermit crabs) and as such, these non‐target interference figures are estimates only.

4.1 OTHER OBSERVATIONS DURING THE FINAL CHECK ON REDONDA Observations on other species present on Redonda were undertaken during the Final Check. Long‐term biodiversity monitoring of seabirds, land birds, lizards, invertebrates, soil and vegetation using standardised, repeatable methods will continue to be completed by RRP, EAG and DOE personnel. This information on population and ecological recovery or changes on the island will support and inform future eradication proposals in the region and internationally.

4.1.1 LIZARD OBSERVATIONS Ground lizards and tree lizards were common across the island; both species were seen every day and in increased numbers compared to during the eradication (Figure 8). Dwarf geckos were seen around the Manager’s house, and in other areas around the island on a number of occasions. Lizard count surveys were completed at a number of sites and these data are available from RRP. Figure 8 Ground lizards on Redonda during the Final Check, June/July 2018.

4.1.2 BIRD OBSERVATIONS Bird species were recorded daily, and birds of interest or significance were reported to RRP and EAG. A complete list of birds seen, and land‐bird counts completed during the final check on Redonda is available from RRP. Increased numbers of Zenaida doves were seen across the island. Pearly‐eyed thrasher, black‐ whiskered vireo, Caribbean martin, barn swallow, American kestrel, peregrine falcon and Caribbean eleania were seen.

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Brown booby, red‐footed boobies, masked boobies, magnificent frigatebirds, brown noddies, sooty tern, red‐billed tropicbirds, were also recorded. In collaboration with University of Roehampton and Anguilla National Trust, 22 GPS tracking devices were deployed on masked boobies to determine foraging location and range of these seabirds.

4.1.3 VEGETATION OBSERVATIONS Photo point counts have been taken to compare vegetation changes between the eradication and final check; these are available from RRP. Vegetation cover has significantly increased across the island with grass, herbs and tree saplings being recorded (Figure 9). Large areas of Ficus saplings were seen across the cliffs (Figure 10). Figure 9 Vegetation on Redonda during the Final Check, June/July 2018.

Figure 10 Vegetation on Redonda during the Final Check, June/July 2018.

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Carolyn Thomas visited Redonda during the final check to update the vegetation list for the island; her report is available from RRP. 5 CONCLUSIONS The eradication of black rats from Redonda has been successfully achieved by a combination ground‐based/hand‐broadcast/aerial operation. This has indicated early benefits for reptiles and land birds and seabirds and other taxa are also likely to benefit. This operation has shown that a well‐planned, adequately resourced, well‐executed programme, with the complete support of the local agencies and government and led by an experienced operator with dedicated volunteers means total eradication of rats on islands is possible and demonstrates how the similar techniques, solutions to difficulties that arose, and protocols can be utilised on similar islands around the world. The Redonda eradication operation had few secondary and primary non‐target species affected by the poisoning programme despite a high level of interference by land crabs. Only one peregrine was affected by secondary poisoning. Much of the island was cleared of rats within two weeks. Bait take levels suggested that rats were spread across the whole island. This activity pattern suggests that rats would have been having a significant effect on seabird and lizard populations on Redonda. The eradication of introduced mammalian predators from islands has become one of the most important tools in conservation worldwide; significant long‐term benefits are achieved, with short‐term investment. For restoration of reptile and seabird populations on islands, rat eradication is an important requirement. The eradication of black rats from Redonda will benefit the lizard and seabird species on the island as well as the invertebrate populations and vegetation regeneration. It will be important to monitor the response of the species (reptiles, seabirds, land‐birds, plants, and invertebrates) present on Redonda following the eradication of black rats. Most species have benefited from rat eradications on islands, but there have also been unforeseen and negative impacts recorded in several projects around the world (Courchamp, et al., 2003; Towns, et al., 2006; Witmer, et al., 2007; Varnham, 2010; Bell, et al., 2011; Bell, 2012). The successful eradication of black rats from Redonda demonstrates how combining the requirements and techniques of both ground‐based and aerial programmes and working through any difficulties that arose during the operation can be utilised on larger islands throughout the Caribbean region. Redonda was declared rat‐free on 31 July 2018. It is important to stress that keeping Redonda free of rats will require constant vigilance and an ongoing commitment from all agencies, interested parties and the community to prevent, detect and respond to any incursions. Clear and simple biosecurity protocols should be developed and followed by all visitors to the island.

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6 RECOMMENDATIONS The authors recommend that: 1. The permanent biosecurity stations are maintained indefinitely as part of the biosecurity requirements for Redonda. 2. Klerat® bait and flavoured wax or resin are used in the permanent biosecurity stations for the ongoing biosecurity procedures on Redonda. 3. RRP, EAG and DOE be responsible for the maintenance of permanent biosecurity stations and other management requirements for the biosecurity on Redonda. 4. Checks for rats continue regularly in the biosecurity stations by the RRP partner agencies and other suitably trained research parties. 5. RRP, EAG and DOE staff and volunteers are trained in identifying rat sign (i.e. teeth marks, chews, droppings, etc.) and implementing biosecurity and incursion procedures in case of a rat being seen on the island. 6. The Redonda Biosecurity Plan is finalised and approved by all stakeholders. 7. The Redonda Biosecurity Plan is reviewed and updated regularly (at least every five years). 8. RRP, EAG and DOE develop an Incursion Response Plan as part of the Redonda Biosecurity Plan and establish a Rapid Response Team to assist in the event of a rat incursion on Redonda. 9. The seabird populations on Redonda continue to be monitored regularly by RRP, EAG and DOE and other agencies such as RSPB and FFI to document recovery and/or changes. 10. The lizard populations on Redonda continue to be monitored every five years by RRP, EAG and DOE and other agencies such as Harvard University and FFI to document recovery and/or changes. 11. The vegetation on Redonda continues to be monitored RRP, EAG and DOE and other agencies such as FFI to document recovery and/or changes. 12. WMIL undertakes regular audit inspections of the biosecurity procedures, protocols and systems and updates training of RRP, EAG and DOE and other interested parties in rodent identification, monitoring and detection. 7 REFERENCES Atkinson, I.A.E. (1985). The spread of commensal species of Rattus to oceanic island and their effects on island avifauna. Pages 35‐81 in Moors, P.J. (ed.). Conservation of island birds. ICBP Technical Report No. 3. International Council for Bird Preservation. Cambridge, UK. Bell, E.A. (2012). Dog Island Restoration Project: the Eradication of Black Rats (Rattus rattus) from Dog Island, Anguilla. Unpublished technical report prepared for Anguilla National Trust, Department of Environment, Government of Anguilla and Fauna & Flora International.

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Bell, E.A., Bell, B.D. and Merton, D.V. (2016). The legacy of Big South Cape: rat irruption to rat eradication. New Zealand Journal of Ecology 40(2): 212‐218. Bell, E., Boyle, D., Floyd, K., Garner‐Richards, P., Swann, B, Luxmoore, R., Patterson, A. and Thomas, R. (2011). The ground‐based eradication of Norway rats (Rattus norvegicus) from the Isle of Canna, Inner Hebrides, Scotland. In Island Invasives: Eradication and Management (C.R. Veitch, M.N. Clout & D.R. Towns), pp. 269‐274. IUCN, Gland, Switzerland. Bell, E.A. and Daltry, J.C. (2012). Feasibility Study for the Eradication of Black Rats Rattus rattus from Redonda, with New Observations on the Island’s Biodiversity and Ecology. Report from Wildlife Management International Ltd and Fauna & Flora International to the Offshore Islands Conservation Programme, St John’s, Antigua and Barbuda. Bell, E.A. and Daltry, J.C. (2016). Operational Plan for the Eradication of Black Rats Rattus rattus from Redonda (Antigua and Barbuda). Report from Wildlife Management International Ltd and Fauna & Flora International to the Redonda Restoration Programme, St John’s, Antigua and Barbuda. Bell, E.A., Ibbotson, J. and Daltry, J.C. (2017). Technical report on the eradication of black rats Rattus rattus from Redonda, Antigua and Barbuda. Report from Wildlife Management International Ltd and Fauna & Flora International to the Redonda Restoration Programme, St John’s, Antigua and Barbuda. BirdLife International. (2012). Important Bird Areas Factsheet: Redonda. Http://www.birdlife.org/datazone/ sitefactsheet.php?id=19939on [Accessed 12 October 2012]. Campbell, E.W. (1991) The effect of introduced roof rats on bird diversity of Antillean cays. Journal of Field Ornithology 62, 343‐348. Courchamp, F., Chapius, J‐L., and Pascal, M. (2003). Mammal invaders on islands: impacts, control and control impact. Biological Review 78: 347‐383. Daltry, J. (2000). The second rat eradication on Praslin Island, Saint Lucia: August –September 2000. Unpublished report to the Saint Lucia Forest and Lands Department and the Durrell Wildlife Conservation Trust. Daltry, J.C. (2007). An introduction to the herpetofauna of Antigua, Barbuda and Redonda, with some conservation recommendations. Applied Herpetology, 4, 97–134. Daltry, J.C., Bloxam, Q., Cooper, G., Day, M.L., Hartley, J., Henry, M., Lindsay, K. and Smith, B.E. (2001). Five years of conserving the ‘world’s rarest ’, the Antiguan racer antiguae. Oryx 35, 119‐127. Daltry, J.C., James, K.J., Otto, A. and Ross, T.N. (2012). Evidence that eradicating black rats (Rattus rattus) has boosted the recovery of rare reptiles and sea birds on Antiguan islands. Island Biodiversity: Flora, Fauna and Humans in the Lesser , 6‐8 November, Martinique, France. Day, M. and Daltry, J. (1996). Rat eradication to conserve the Antiguan racer. Aliens 3, 14‐15.

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Devine, B., Drayton, N., Lindsay, K., Thomas, T., Cooper, B. and Nieves, P. (2010) Protected Areas Analysis for Antigua and Barbuda: Assessment and Mapping of Antigua and Barbuda Ecosystem Resources and Promoting a System of Protected Areas for Antigua and Barbuda. Unpublished technical report submitted to Ministry of the Environment, Government of Antigua and Barbuda. Havery, S.J., Lawrence, S.N., Daltry, J.C. and Bell, E.A. (2014). Technical Report for the Eradication of Black Rats Rattus rattus and Small Asian Herpestes javanicus from Pelican and Codrington Islands, Antigua. Report for the Offshore Islands Conservation Programme, St John’s, Antigua and Barbuda. Hedges, S.B. & Conn, C.E. (2012). A new skink fauna from Caribbean islands (, Mabuyidae, Mabuyinae). Zootaxa 3288, 1‐244. Horwith, B. & Lindsay, K. (1997). A Biodiversity Profile: Antigua, Barbuda and Redonda. East Caribbean Biodiversity Programme Publication 3. Island Resources Foundation, USA. Howald, G., Donlan, C.J., Galvan, J.P., Russell, J.C., Parkes, J., Samaniego, A., Wang, Y., Veitch, D., Genovesi, P., Pascal, M., Saunders, A. and Tershey, B. (2007). Invasive rodent eradication on islands. Conservation Biology 21, 1258‐1268. Howard, R.A. (1962). Botanical and other observations on Redonda, the . Journal of the Arnold Arboretum 63, 51‐66. Jones, H.P., Tershy, B.R., Zavaleta, E.S., Croll, D.A., Keitt, B.S., Finkelstein, M.E. and Howald, G.R. (2008). Review of the global severity of the effects of invasive rats on seabirds. Conservation Biology 22, 16‐26. Lawrence, N., James, K., Otto, A., Ross, T.N. and Daltry, J.C. (2013). Is eradicating rats worth it? Impacts observed on Antigua’s offshore islands. Program and Abstracts: Society for the Conservation and Study of Caribbean Birds, 19th Regional Meeting, July 26‐31. Georgetown, Grenada. Lawrence, S.N. and Daltry, J.C. (2015). Antigua announces its 15th island cleared of invasive alien mammals. Oryx 49, 389. Lindsay, K. and Horwith, B. (1997). A Vegetation Classification of Antigua, Barbuda and Redonda. East Caribbean Biodiversity Programme Publication 2. Island Resources Foundation. Long, J.L. (2003). Introduced Mammals of the World: Their History, Distribution and Influence. CABI, Wallingford, UK. Lowrie, K., Lowrie, D. and Collier, N. (2012). Seabird Breeding Atlas of the . Environmental Protection in the Caribbean, Sint Maarten, Netherlands Antilles. Malhotra, A. and Thorpe, R.S. (1999). Reptiles & Amphibians of the Eastern Caribbean. Macmillan Education Ltd., London, UK. Martin, A.R.; Richardson, M.G. (2017). Rodent eradication scaled up: clearing rats and mice from South Georgia. Oryx: 1‐9. DOI: 10.1017/S003060531700028X

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Moors, P.J. and Atkinson, I.A.E. (1984). Predation on seabirds by introduced animals and factors affecting its severity. Pages 667‐690 in Croxall, J.P, Evans, P.G.H. and Schreiber, R.W. (Eds.). Status and conservation of the world’s seabirds. ICBP Technical Publication 2. Morse, A.R. (1979). The Quest for Redonda: the Quest for M.P. Shiel’s Realm of Redonda. The Reynolds Morse Foundation, Cleveland, Ohio, USA. Office of the Prime Minister. (2001). Biodiversity Strategy and Action Plan for Antigua and Barbuda. Government of Antigua and Barbuda, St John’s, Antigua and Barbuda. Parks and Wildlife Service. (2014). Evaluation Report: Macquarie Island Pest Eradication Project, August 2014. Department of Primary Industries, Parks, Water and Environment. Hobart . Prosper, J., Joseph, V., Otto, A. and Prosper, S. (2008) Antigua and Barbuda. In Important Bird Areas in the Caribbean (eds D.C. Wege & V. Anadon‐Irizarry), pp. 35‐46. BirdLife International, Cambridge, UK. Sylvester, I., Joseph, V., Prosper, J., Prosper, S. and Hay, B. (2009). Antigua‐Barbuda‐Redonda and Selected Offshore Islands. An Inventory of Breeding Seabirds of the Caribbean (eds. P.E. Bradley & R.L. Norton), pp. 169‐175. University Press of Florida, USA. Towns, D.R. and Broome, K.G. (2003). From small Maria to massive Campbell: forty years of rat eradications from New Zealand islands. New Zealand Journal of Zoology 30, 377‐398. Varnham, K. (2010). Invasive Rats on Tropical Islands: Their History, Ecology, Impacts and Eradication. RSPB Research Report No. 41. Royal Society for the Protection of Birds, Sandy, United Kingdom. Varnham, K. and Daltry, J.C. (2006). Eradication of Invasive Black Rats (Rattus rattus) from Green and York Islands, Antigua: June‐July, 2006. Unpublished technical report to the Mill Reef Club and partners of the Antiguan Racer Conservation Project. Witmer, G.W., Boyd, F. and Hillis‐Starr, Z. (2007). The successful eradication of introduced roof rats (Rattus rattus) from Buck Island using diphacinone, followed by an irruption of house mice (Mus musculus). Wildlife Research 34, 108–115.

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8 APPENDICES 8.1 TIMETABLE OF ACTIVITIES FOR THE REDONDA FINAL CHECK (14 JUNE 2018 TO 2 JULY 2018) ACTIVITY DATE Planning and preparation  Elizabeth (Biz) Bell arrived 10/6/2018  Meetings 11/6/2018  Flavoured wax made  Meetings to finalise equipment and operational planning 12/6/2018  Salina Janzan arrived  Equipment check at Seaton’s shed  Flavoured wax made 13/6/2018  Food purchased Phase I: Establishing monitoring grid  Biz and Salina to Redonda 14/6/2018  Established base camp  Lines FA, Visitor (N) and Permanent (S) established on top of island (chocolate wax used) 15/6/2018  Lines FB, FC and FD established on top of island (chocolate wax used) 16/6/2018 Phase II: Monitoring  Top monitoring check 1: Chocolate wax 17/6/2018  Top monitoring check 2 (A, B and N): Chocolate wax 18/6/2018  Rain  Top monitoring check 2 continued (C, D and S): Chocolate wax 19/6/2018  Scramble line FSA established (chocolate and aniseed wax and tracking tunnels)  Top monitoring check 3 (N): Chocolate wax  Helicopter (food and supplies) 20/6/2018  Lizard monitoring  Land bird monitoring  Top monitoring check 3 (A and B): Chocolate wax  Scramble line FSB established (chocolate and aniseed wax and tracking tunnels) 21/6/2018  Rock on Salina’s foot  Top monitoring check 3 (C and D): Chocolate wax – half only as rain made area too slippery and dangerous 22/6/2018  Scramble A check 1: Chocolate and aniseed wax and tracking tunnels  Rain  Top monitoring check 3 (C and D): Chocolate wax 23/6/2018  Scramble B check 1: chocolate and aniseed wax and tracking tunnels  Top monitoring check 4 (A, B and N): Chocolate and aniseed wax – half only as rain made area too slippery and dangerous 24/6/2018  Scramble A check 2: Chocolate and aniseed wax and tracking tunnels  Helicopter (food and supplies)  Shanna, Adam and Waldo arrived 25/6/2018  GPS loggers deployed on 10 Masked boobies  Shoreline monitoring stations established (chocolate and aniseed wax)  Top monitoring check 4 continued (S): Chocolate and aniseed wax 26/6/2018  Scramble B check 2: chocolate and aniseed wax and tracking tunnels  GPS loggers deployed on 12 Masked boobies  Top monitoring check 4 continued (C and D): Chocolate and aniseed wax 27/6/2018

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 Scramble A check 3: chocolate and aniseed wax and tracking tunnels  Scramble B check 3: chocolate and aniseed wax and tracking tunnels  Top monitoring check 5 (A and B): Chocolate and aniseed wax  Lines A and B removed  Lizard monitoring 28/6/2018  Land bird monitoring  Check of the Hanging Gardens using rope access techniques  Top monitoring check 5 continued (N): chocolate and aniseed wax  Scramble B check 4: chocolate and aniseed wax and tracking tunnels  Scramble B removed 29/6/2018  Shoreline monitoring check 1: chocolate and aniseed wax  Shoreline monitoring removed  Removed 6 loggers from masked boobies  Helicopter (food and supplies)  Adam and Waldo departed Redonda  Top monitoring check 5 continued (C and D): chocolate and aniseed wax 30/6/2018  Lines C and D removed  Removed 7 loggers from masked boobies  Scramble A check 4: chocolate and aniseed wax and tracking tunnels  Scramble A removed  Vegetation survey 1/7/2018  Top monitoring check 5 continued (S): chocolate and aniseed wax  Removed 2 loggers from masked boobies  Packed camp  Helicopter  Visitors to view the project 2/7/2018  Removed 1 logger from masked boobies  Whole team departed Redonda Project debrief  Equipment cleaned and sorted  Debriefing meeting with Shanna and Sophia 3/7/2018  Salina left Antigua  Reporting and data entry 4/7/2018  Meeting with Ashton  Reporting and data entry 5/7/2018  Equipment collected by Sophie for use on other project (Redonda Marine Survey)  Reporting and data entry 6/7/2018  Biosecurity meeting with Shanna  Reporting and data entry 7/7/2018  Reporting and data entry 8/7/2018  GPS tracking download and data management with Shanna Departure  Biz departed Antigua 22/7/2018 Rat‐free status  Rat‐free status declaration 31/7/2018

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