Mice on Gough Island

Tristan da Cunha is remote, by any standards.  But within the archipelago that Tristan encompasses, there is an island that is considered remote even by the people of Tristan. Around 220 miles further south from Tristan is Gough Island, named after Capt. Charles Gough of the ship called the Richmond, who discovered it in 1732.

Gough Island is around 13 km long and 5 km wide.  It is home to around 10 million seabirds as well as two species of land birds – the Gough Bunting and the Gough Moorhen.  In recognition of Gough being a hugely important place for bird life, with a unique largely unspoiled habitat, the island became a UNESCO World Heritage Site in 1995.  It’s classification was added to by being joined by Inaccessible Island (another small island in the Tristan archipelago) in 2004.

Gough Island is uninhabited.  However, for the last 62 years the South African Weather Service has had a lease arrangement with the Tristan Government, and during this time it has maintained a scientific base on the island.  Teams of staff spend an uninterrupted 12 months on the island, the main purpose of which is to monitor weather conditions in order to help with the forecasting of weather in southern Africa.  In addition to the meterologists, the team includes engineers and a medic. There are also normally three staff from the RSPB (Royal Society of the Protection of Birds) who are bird scientists, and whose job it is to monitor the bird population on Gough.

The South African met station on Gough Island             Photo – Richard Hall

The importance of Gough can be seen, for example, in the fact that 99% of the world population of Tristan Albatross nest on the island, and 100% of Gough Buntings nest there.  Both species are critically endangered.  There are also populations of a large range of other Albatross, Shearwater, Petrel and Prion species, some of which are also classified as being endangered.

Tristan Albatross and chick                                                                      Photo – Steffen Oppel

Around 2006, the use of camera traps was able to prove conclusively what a few observers had already suspected.  This is that mice were predating on the wild bird chicks.  Mice had been on the island for many years, probably brought there originally by sealers in the 19th century.  The mice lived in harmony with the bird population, their diet consisting of plant seeds and insects.  Then – they evolved into chick-eaters.  This evolution, the change in eating habits of mice, has been seen in a parallel situation on Marion Island, where by means of careful monitoring during the space of just four seasons, ‘normal’ mice had evolved into predators of bird chicks. The scale of this predation on Gough is enormous – in 2016 it was estimated that mice were responsible for the killing of 600,000 chicks.  Following a scientific study on Gough some weeks ago, this has now been revised and updated to 2 million chicks and eggs a year. There have been some quite gruesome pictures of groups of mice eating albatross chicks alive.  The interesting thing is that the parent albatross just looks on unconcerned.  One stab of the adult albatross beak could easily kill a mouse, and bear in mind that an adult albatross might weigh 2 kg as compared to a mouse of about 25 grams.  The problem is that the Albatross (and other species) have nothing in their genetic makeup to tell them that mice are dangerous.

Mice on an albatross chick – while the adult looks on                            Photo – Ben Dilley

The RSPB team stationed on the island, together with visiting specialists in September / October this year, came up with some alarming figures.  For example, they found that this year the population of the critically endangered Tristan Albatross reared just 309 chicks from of 1,435 nests – only 21% instead of the 80 – 100% that would be the target for the species to have a long-term future.

In recent years, just as there have been huge technical advances in camera traps and other monitoring devices, so also there have been major advances in rat and mouse eradication from islands.  Islands lend themselves to eradication programmes since, provided that strict bio-security measures are introduced and enforced, re-infestation can be prevented, whereas in any mainland situation re-infestation is inevitable.  There have been some highly successful island eradication programmes, including from South Georgia, Macquaire Island off Australia and Campbell Island off New Zealand.   All of these programmes have used helicopters with underslung spreaders that distribute pellets made of a cereal-based toxic bait.  The spreaders are standard agricultural fertiliser spreaders fitted with a small Honda engine, and the bait generally used is one of the second-generation anticoagulants called Brodificoum.

The world centre for this eradication work is New Zealand, and it was that country that the RSPB turned to when it set about the planning stages of an eradication programme on Gough Island.  Initially, the plan was to carry out the eradication programme in the winter of 2019, but this has now been postponed to 2020.  The winter months are chosen because it is at that time that there are no birds nesting, and the mice are keen to find all food alternatives – making them eager for the toxic bait that is used in the eradication programme.

In August + September this year, a small specialised team travelled out on the SA Agulhas 2, the ship used by the South African Government to conduct their annual maintenance and team-change visit on Gough Island.  This team was organised by the RSPB, and consisted of an eradication specialist and a specialist helicopter pilot (both from New Zealand), an aerial systems engineer, and a bird captivity and release specialist.  The purpose of the visit was to have a detailed look at the site so that they could modify and confirm a master-plan for the operation, in order to give this expensive operation the highest possible chance of success.

The interior of Gough Island showing ‘Hag’s Tooth’                               Photo – Richard Hall

The overall plan is that in the early winter of 2020, a logistical team will travel out to Gough Island, to take out stores and set up accommodation on the island – a team of around 30 people will be needed.  The bird captivity and release specialist will be in this advance party.  His role will be to set up a large aviary-type structure, and to capture a good number of buntings and moorhens to act as a security population.  If these species suffer from poisoning of the toxic bait, at least there will be a protected reserve of such birds in captivity, available to be released when the active bait is no longer present on the island.  The albatrosses and the rest of the sea birds do not pose a problem in this respect – the do not come to the island during this time of year, and in any case they do not eat while they are onshore.

Once all the on-island preparations have been completed, the dosing team will travel to the island on a second ship.  This team will include four helicopters (one as a reserve) and a whole team of specialist pilots.  The systems engineer sets out an electronic GPS-based grid pattern of the routes to fly to ensure 100% coverage – indeed each swath is arranged to give 50% coverage of the previous swath, thus arriving at a double dose of the toxic pellets for any given area.  Two applications of bait would be spread, ideally 3 weeks apart for maximum effectiveness.  The winter in these latitudes can be very severe, and it is anticipated that with any lull in the weather the team will have to work from dawn to dusk, to seize the opportunity before the weather closes in again.

No-one is pretending that the task will be simple.  Mice are more difficult to eradicate than are rats, partly because they can find protection from the weather (and the toxic bait) in all sorts of caves and holes.  The whole project is expected to cost in the region of £9 million.  The success of the project will be measured by two elements.  Firstly, 100% kill of the mouse population is needed.  If a single breeding pair remain, then the breeding birds will just have a short respite until the mouse population once again builds up to the present levels.  Secondly, it is vital that the bio-security arrangements in Cape Town and on the island must be so thorough and so effective that there is no possibility of the re-introduction of mice in the future.  I am sure that everyone involved in the project knows full well that they have just one chance to succeed.

A group of Yellow Nosed Albatross, nesting on Nightingale Island

Extraordinary people on TDC

With the development of the society in such a very remote place as Tristan da Cunha, going back over 200 years, it is not surprising that there are some extraordinary aspects to the people on the island, both as far as individual people are concerned, and also relating to how some noteworthy social customs have developed.  That is not, however, the limit to the incidence of extraordinary people on the island.  Some of the expat staff stationed here certainly fit into this category, and some of the visitors also deserve a mention.  All in all, it seems that through its extreme remoteness the island does nurture and attract people who are extraordinary!

Through the eyes of a visitor to the island, some of the working practices are remarkable.  In particular it is astonishing how all members of the community come together for specific work tasks.  For example, when a ship has to be unloaded everyone leaves their normal places of work and becomes part of the unloading team – working as a stevedore on the ship, manning the barges bringing cargo into the harbour, driving a relay of tractors and trailers from the harbour to the warehouse, unpacking crates, and being part of a human chain to stack boxes in the warehouse. There are other events when an ‘all hands day’ can be declared – for example when everyone is needed to replace a roof on a house.

Islanders teamed up to re-roof the church

There are also the examples of remarkable people in connection with the island fishing industry.  For the most part, fishing on Tristan means crayfish fishing.  Each boat is crewed by two men, and eleven small open boats go out on the days that have been declared as ‘fishing days’.  The boats make a very early start, the little boats wallow horribly in the water particularly when they are not making way when the pots are being hauled.  The boys leave the harbour at first light, and in the shoulder months the low temperatures and the chill factor can be really testing. Every man a hero!

Fishing boats coming back into harbour at the end of a long day

Once the crayfish are landed, they are transported to the factory.  The people who work at the factory are also remarkable.  During the week it is largely pensioners who do this work, some of them approaching the age of 80.  They may work for 8 hours or more during the day, or in the evening the factory siren may call them out for an evening shift of anti-social hours.  The Tristan fishing industry is dependent on this reliable and loyal work-force.  It is another example of the extraordinary people of Tristan.

It should not be thought that all Tristanians are alike – they may come together for specific tasks, but they are generally highly individual.  The population today is just 250 people, and I could probably detail them one by one to show how a high proportion of them are individually extraordinary – but that would not go down well on the island.  I must not be seen to have any sort of bias or favouritism!

At any one time, there are around 12 – 15 expatriates stationed on Tristan.   For example, at present these include three teachers, a doctor and a nurse, the Administrator, a finance man, a factory manager and engineer, a retail specialist, and an agriculturalist (me!), as well as a short-term postdoctoral researcher from the Natural History Museum.  Most of these expats are on 2-year contracts, except for the Administrator who is generally here for three years and the doctor who may be here for five months.  In a general sense, the expats can be described as being extraordinary.  They have committed themselves to spending a couple of years on a tiny island where the facilities are extremely limited (shops, restaurants, healthcare facilities, etc), where they leave behind family and friends, and for the most part where the opportunities for professional contact and CPD (Continuous Professional Development) are quite limited.  These privations are not for everyone!

As a result of Tristan’s location, deep in the South Atlantic, there are many scientists and specialists who come to the island.  In the course of the two years that we have been here somewhere over 140 people have passed through.  These may be fisheries experts, conservation specialists, seal experts or bird professionals.  They may be South African personnel going to Gough Island for a 12-month tour of duty, or the team coming off Gough after their 12-month stint.  They may be the construction staff who built the new health centre, many of whom had experience in Antarctica.  Or they may be specialists in seismology, volcanology, global magnetism or nuclear detection.  It is a real experience for the people on Tristan, both Tristanians and expats, to be able to have contact with all of these visitors, many of whom can be described as extraordinary.

Of special mention is the dentist from Edinburgh, who comes to the island every year for three week’s work, bringing her daughter with her.  Her much-travelled daughter slots back into the little school on Tristan, where she catches up with all her island friends.  This must be the most extreme example of taking your child to work with you!

A cruise ship at anchor off Tristan
Our dutch friends at the harbour, with their yacht at anchor behind them

We also have a small number of tourist-related people coming to the island.  A few small cruise ships make a visit, weather permitting, as do a small number of sailing yachts.  That gives us a further  chance to meet some more extraordinary people.  I am thinking here of the two Dutch men in a yacht, who stopped off to buy some groceries and then continued on to Melbourne and finally Adelaide, stopping off on the way at Les Isles de la Desolation.  I am also thinking of the young girl who sailed single-handed from Sweden to Tristan – real adventurers come to Tristan!  And how about the cruise-ship tour guide who came earlier this year – it materialised that before that job, she had joined her partner on a small wooden yacht deep in Brazil.  They sailed the ‘wrong way’ round Cape Horn, and in two years they sailed back to Norway – in fact she made history by becoming the first Norwegian female ever to sail through the North West Passage.  After passing eastwards through the North West Passage, they of course passed Baffin Island – this is the home of another extraordinary visitor we had here for a few weeks this year!

Yacht Lady Free ice bound going through the North West Passage (Photo Cecilie Evjen)
Yacht Lady Free approaching a Beluga whale (Photo  Jan Martin Nordbotten)

 

 

 

 

National Geographic Visit

Firstly, it is time to apologise. The process of getting these ‘letters from Tristan’ onto the site is a slightly protracted one, and we have been having problems.   The last time I myself was able to put the blog onto the website was when we were in Cape Town, three months ago.   It is out of the question to do it from here – the internet system is not nearly good enough.   So I have had to do it the long-winded way.   I write the posts and I edit the photographs, reducing them in size and adding the water-mark and a caption. Then this all gets emailed to a friend in the UK, two at a time as far as the photographs are concerned. This is the same process that even the Tristan News website has to go through.   Then my friend finds time in his busy diary to spend the 15 minutes needed to put it all on WordPress. Trouble is, he has become even busier.   Hence, for example, poor Nena and Mike’s wedding had to wait four weeks before my contact was able to get the blog published. The knock-on effect of this has been that my creative pen has been put to one side, so as not to create a huge log-jam of posts!

Apologies for this. Hopefully we are sorted now and there will be a regular flow of observations from these remote shores.

Rockhopper Penguins nearing the end of their moult

We had a three-week visit from a team from the National Geographic, which will probably have far-reaching consequences for the Island.   This was largely a research visit, as part of their Pristine Seas project. The team travelled on a chartered ship called Grenville, and they spent their three weeks on and around the four main islands (Tristan, Nightingale, Inaccessible and Gough Islands)

As you may expect from the Pristine Seas title, the scientists on board focussed very largely on the seas around the islands. A huge range of scientific processes were carried out, and there seemed to be specialists in everything imaginable. Not surprisingly, one of the main conclusions was that the seas around the islands of Tristan da Cunha are in extremely good health, outstandingly so when compared with anywhere else that they have done these studies so far. I say ‘not surprisingly’ because we are a dot in the middle of the southern Atlantic Ocean, with a tiny permanent population of 263 persons for a sea area of thousands of square miles, and with the only exploitation being a crayfish industry working to a managed quota system and the very occasional ship being allowed under licence to fish for pelagic fish (always with an observer from the Tristan Fisheries Department on board)   The waters should be pristine!

Looking north from the Big Gulch

The team included a top-level film crew, and the aim is to produce film footage of Tristan which is likely to go global later in the year. It is for this reason that I mentioned ‘far reaching consequences’, for it seems likely that the image and reputation of the island will be greatly enhanced. We were all invited to a presentation in Prince Philip Hall on their final night, with a short film summary of the three weeks they spent and short technical summaries from the leading specialists.   The idea is that some of the team come back later in the year to share with us all the meat of their findings, and finished footage of their filming. We are so much looking forward to this, and I will place on this website details of when their details will appear on television.

An unusual visitor to these shores – a King Penguin here to moult. Note – check out the tail of the South Atlantic Fur Seal behind him!

One important feature of the National Geographic visit was that they enjoyed exceptional weather! They had factored in a 40% weather-related down-time in their planning – but in reality they were able to operate 100% of the time. This meant that they were able to achieve far more than they had hoped, and the film crew nearly ran out of digital memory!!

The team managed nearly 300 dives during their three weeks. On every dive they sighted crayfish, which gives an idea as to how well-stocked these waters are. They also filmed a fish that remains unidentified – evidently a never-seen-before species, or one that is exceptionally rare. Also they saw a porbeagle shark, the first one ever seen in the Southern Atlantic. Readers on the west coast of Scotland will be very familiar with the porbeagle. Talking of sharks, they carried out a shark tagging programme (rather them than me!) These tags are implanted onto the shark’s side; after six months the tag is released from its implanted stem and floats to the surface, whereupon it tunes into a satellite and ‘calls home’ with all the data of its travels in six months, – where it has been and at what depth.

The last of the National Geographic team going out to Grenville

It was a pleasure to meet many of the National Geographic team, and we look forward to seeing them again.

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