Friday, 1 September 2017

North island myna eradication project as told by Claire and Sarah

What is the Common Indian Myna (Acridotheres tristis)? The myna is a bird native to India and South East Asia which has been introduced to various countries around the world. The myna was introduced to the Seychelles potentially to manage the number of insects damaging crops and other vegetation, however this is not confirmed. Is is an aggressive bird that has been known to injure and kill endemic birds as well as damage the eggs.  This has had a severe impact on breeding success and population numbers of endemic species across the islands.

North Island is working towards restoring the island to how it was before it became a farm for fruit, vegetables and coconuts in 1826. Removal of the myna is a huge step in this process and once completed endemic species can then potentially be reintroduced. The Myna Eradication Programme is a partnership of North Island, Green Island Foundations, Chris Feare of Wildwings Bird Management and endorsed by Ministry of Environment,Energy, and Climate Change.  The current programme commenced May 2016 and has since removed 924 myna from North Island.

Photo: partial view of North island seen spa hill  (CWaters)

Our current volunteers, Claire Waters and Sarah Atkinson took over in April 2017 for the final stages of the eradication. We are now reaching a very exciting part of the project where we are starting to see huge progress and can see we are reaching the end of the eradication process. The eradication of the myna has been successfully completed on two other islands in the Seychelles archipelago (Frégate and Denis); which have shown a notable dramatic increase in the native bird population on those islands. The eradication of the majority of mynas on North Island is already benefiting the native species on the islands and is thus proving its conservation importance.

In order to remove the myna, the methodology has changed since the beginning of the project to adapt to the birds’ changing behaviour. In order to be successful in removing the mynas, efforts need to be invested in understanding the bird behaviours and adapting methodologies accordingly. We are now in the process of carrying out surveys throughout the day to locate the remaining birds, which are thought to be in very low numbers.

So what do we do every day? Each day starts at 5:30am where one of the two Myna Eradication Officers, Claire or Sarah, start with a dawn survey at various locations across the island. This involves listening and looking for a dawn chorus, which is easily distinguishable from other birds around the island. Surveys then continue throughout the day, tracking the remaining birds and covering all areas of the island, from the plateaus to the top of the hills along the hiking trails. The other volunteer will begin work at midday, and will carry out the same survey at dusk to locate the birds as they select a tree to roost in overnight.
Photo: Sarah and Claire observing mynas (ASanders)

Interestingly, a previous Myna Eradication Programme on Denis Island found that the myna would roost in one tree together overnight. This has also been suggested to take place around the world. However, on North Island the myna have all been found to roost in pairs across the island. This is one example of the differing behaviour found in the myna on North Island and has made the project more challenging.

It has been found that as the number of myna on the island has dropped significantly, their behaviour has begun to change as well. Their vocalisations have altered to mimic native birds making it more difficult to locate them. This may be in response to low population numbers or in an attempt to disguise themselves. It is also possible that juveniles are learning from native birds in the absence of many adults to learn from. They have also become less confident and are no longer seen on the ground of the plateau. In the coming months, as we near completion of the eradication, there will then be an observation phase of the project, where the island will continue to be surveyed daily to ensure that we have eradicated all birds, this may take place for up to 6 months.

Since the start of the myna eradication, North Island staff have already noticed a significant increase in the numbers of endemic species. This includes the Seychelles Blue Pigeon (Alectroenas pulcherrima) and the Seychelles Sunbird (Necttarinia dussumieri) and is a huge positive step in restoring the island and conserving the unique wildlife of the Seychelles.

Photo: Seychelles white eye on North island (CWaters)

Saturday, 19 August 2017

Rabbit fish research at Denis island

Rabbitfish are the main targeted fish species of the artisanal fishery of Seychelles, consisting of approximately two-thirds of the total annual catch. They are herbivorous and have been shown to help keep reefs healthy by grazing on invasive algae. With such commercial and environmental importance, Ameer chose to dedicate his PhD research to investigating the role that rabbitfish play in a marine environment, and their contribution to the resilience of tropical coral reefs. His research is crucial to small island states like Seychelles, as these regions rely heavily on tourism and fisheries for sustenance.

Ameer is currently conducting research on Denis Island for the fourth part of his thesis. He is specifically investigating the diurnal home range of rabbitfish around Denis Island and what factors, including tidal phase, habitat type and complexity, influence their movements.

                                    Photo (AEbrahim): Ameer conducting research in lagoon at Denis 

Denis Island has two very distinct habitats: vast corals reefs and lush seagrass meadows. Research from other parts of the world is increasingly demonstrating that coastal habitats, such as coral reefs, do not function in isolation but rather as part of a larger habitat network.  Other habitats such as seagrass meadows lie in close proximity to coral reefs, allowing for reef dwelling organisms and materials to travel among these habitats. Numerous species of commercially important herbivorous reef fish, such as rabbitfish, may frequent these habitats through diurnal and tidal fish migrations.

Accordingly, Ameer has dispersed 34 acoustic receivers encompassing the seagrass meadows and coral reefs in both shallow and deep water environments around Denis Island. Each receiver has a range of approximately 250m, allowing them to track the rabbitfish that Ameer has tagged using internal acoustic tags.

                                   Photo (AEbrahim): Placement of acoustic tags 

In many regions of the world, including Seychelles, connected habitats like seagrass meadows are often forgotten when it comes to conservation management. Therefore, this part of Ameer’s PhD will also assist in determining whether rabbitfish are frequenting different habitats such as seagrass meadows, thereby aiding conservation management efforts. Furthermore, his research will hopefully help cement future marine conservation management for the waters surrounding Denis Island. He is now in the process of collecting his data for this research. 

Friday, 28 July 2017

Training in threatened species identification and data gathering protocol

Yesterday, we hosted a training session on threatened species identification, field survey technique and data gathering protocol in the context the project “The development of a co-management plan, designed by fishers to minimise the impact of the Seychelles artisanal fishery on threatened species” also known as the Threatened species project.
Photo: Participants  at the training with the Green Islands Foundation team (MLeotta)

The objective of the Threatened species project is to reduce the Seychelles artisanal fishery’s impact (catch, by-catch and disturbance) on globally threatened species (IUCN classifications: VU, EN, CR).  The project is developing a baseline of threatened species occurrence in the artisanal fishery through fisher interviews and consultation, literature review and an intensive 12-month survey of artisanal catch. The project will support fishers in the identification and development of pragmatic management measures to reduce artisanal fishing pressure on threatened species - (e.g. catch release, only landing mature individuals, reduce effort on critical habitats, gear modification etc…).

Yesterday’s training was organized for collaborators, these are civil society members who assist Green Islands Foundation in collecting species-specific data on IUCN red listed threatened species and species of local concern. In addition, fisheries technicians from SFA were also invited to attend. Mr. John Nevill, Technical Fisheries Advisor on the project carried out the training. The participants given an introduction to the project, presented the species monitored under the project, the monitoring protocol and were shown some initial results from the first four months of data collection.
There are 20 threatened species of teleosts, sharks and rays that are known to occur in artisanal catch in Seychelles.  In addition, there are a number of species that were identified as of local concern at the start of the project also monitored trough this project.
Photo: Slideshow presentations on fish identification (MLeotta)

Through the presentations, Mr. Nevill showed participants how properly identify species and their distinctive characteristics. Participants were given each an Identification card showing all the threatened species monitored through the project that they can use on the field. They were also shown how to properly take measurements through practical sessions in the laboratory at the Seychelles Fishing Authority.  
Photo: Practical session ; how to record total lenght in sharks (MLeotta)

We expect through this training that the participants will be better equipped to collect species-specific data on the field to inform fisheries management decisions.   

Monday, 24 July 2017

Seychelles magpie robin population census on Denis Island, June 2017

A total of 76 individual Seychelles magpie robins were observed during a population census of the species on Denis Island from13-20 June 2017. Fifty seven of the robins observed were ringed and 19 were unringed.  In addition to censusing the population, 12 of the unringed robins were captured and ringed. A total of seven SMR were still unringed at the end of our time on Denis.

Following cat Felis catus and rat Rattus rattus eradications and rehabilitation of native broadleaved woodland habitat, twenty Seychelles magpie robins Copsychus sechellarum (SMR) were introduced to Denis Island in June 2008 as part of a national recovery programme for the species (Burt et al. 2016). For the first two years post translocation the robins were supplementary fed on a daily basis, but supplementary feeding ceased in 2010. Management currently involves the provision of nest boxes, ringing new recruits to the population, and to clearing relatively small areas of fouzer taba fern Nephrolepis biserrata to improve the foraging habitat for the robins within the forested conservation zone.
The purpose of this work was to (i) estimate the current SMR population size on Denis, (ii) map approximate territory locations and identify territory occupants and (iii) ring unringed SMR with metal ID ring and an individually identifiable colour combination.

Photo: Seychelles Magpie robin (KlartjeePuttemans)

The census was undertaken by Rachel Bristol and Indira Gamatis from 13-20 June 2017. All areas of the island were searched several times for SMR. All robins seen were identified i.e. ring combination recorded, and the number and age (adult/ juvenile-based on plumage) of unringed birds was also noted. The locations of individuals and group composition (i.e. who was hanging out with who) was also recorded.
Unringed robins were caught, ringed, measured and blood sampled. They were captured mostly using a spring trap baited with live termites, but also with a mist net using termites as an attractant.

Population size, trend and age structure
A total of 76 magpie robins were seen on Denis during this census. Two of the original robins translocated from Frégate Island are still present. These two males are a minimum of 10 years old as both were adults at the time of translocation to Denis in June 2008. Nineteen individuals, almost all of which were juveniles, were unringed. These 19 individuals represent productivity over the past year. The population trend is increasing, see Figure 1. We are confident this census is fairly accurate, however it is possible a few individuals were undetected, therefore this population estimate of 76 confirmed individuals can be considered conservative.

Figure 1. Trend in Magpie robin population size on Denis Island from introduction in 2008 till present
(Data sources: Burt et al. 2016; Denis Island magpie robin monitoring records; Bristol & Gamatis 2017)
Twelve robins were ringed during this census. Biometric measurements and blood samples were taken from all individuals ringed. Seven individuals were still unringed at the end of our time on Denis.

Photo: Magpie robin juvenile with new rings (R.Bristol)

Territories (location and number) appear to have changed little since the last accurate monitoring in 2016. There appear to be 18 territories on Denis each occupied by 2-6 robins. However we were not on the island for sufficient time to assign all individuals to territories with certainty, or to confirm possible shifts in territory boundaries.

Thank you as always to Green Islands Foundation (GIF) and Denis Island management for enabling this census and providing transport, accommodation and meals.

Bristol RM and Gamatis I (2017) Seychelles magpie robin population census on Denis Island, June 2017. Unpublished report.

Burt AJ, Gane J, Olivier I, Calabrese L, de Groene, A, Liebrick T, Marx D, Shah N (2016) The history, status and trends of the Endangered Seychelles Magpie-robin Copsychus sechellarum. Bird Conservation International 26, 505-523. doi: 10.1017/S0959270915000404.

Friday, 7 July 2017

Project to re-establish a breeding colony of Sooty terns on Denis island

When Denis Island was discovered in 1773 it hosted large seabird populations including a colony of Sooty Terns (Sterna fuscata). In the following years the birds left, due to various reasons mainly habitat change. To re- establish a colony an area of a former coconut plantation was cleared as the Sooty Tern is a ground nesting species that requires open grassland. Since the Sooty Tern re-colonization project initiation in 2008, preparation of the site prior to the breeding season has always preoccupied keen environmental enthusiasts on Denis Island. This includes the removal of encroaching plants and trees, the cutting of grass to a suitable height and placing the Sooty models and loud speakers. This project is unique, based on the knowledge and under the supervision of Prof. Chris Feare. The dummy birds and the playing of the Sooty colony noise through the speakers shall encourage the birds to nest on the prepared site.

Monitoring commences every year around May with the arrival of the birds. This year we had a few weeks delay mainly in obtaining the needed broadcasting equipment. By late June the set-up design at the South Point were completed. Within the weeks a few birds were seen circling/flying over the breeding site. Visual observations were mainly opportunistic partly due to lack of staff and other work.

Similar to last year, unfortunately it seems this year is also an odd year with regards to Sooty Terns nesting, presumably related with abnormal weather patterns and consequences for fish stock and seabird activity. On Bird Island, Prof. Chris Feare, reported that breeding activity got off to an early start but tailing off early with no new birds coming in. Incubation shifts are a bit longer than normal suggesting that food might not be as available as normal. The laying season normally ends mid-July but after an early start it might end early this year.

Sooty Terns  formerly nested on several islands in the Seychelles group but on most islands, especially the smaller ones, colonies became extinct as a result of excessive egg and adult harvesting by people, introduction of exotic predators, and habitat change. Commercial harvesting of eggs continues on some islands and forest development in one of the larger colonies, on Aride Island, is now limiting the numbers that can nest there. Provision of alternative nesting areas on which they may breed may thus play an important part in maintenance of sooty tern populations in Seychelles. On Denis Island we are attempting to re-establish a sooty tern colony through habitat management, decoy birds and playback of recorded sooty tern calls.