Gough Island, part of the UK Overseas Territory of Tristan da Cunha located in the remote South Atlantic, is considered one of the most important seabird islands on the planet. A World Heritage Site, this small spec in the ocean is known to support millions of breeding seabirds, including the iconic Critically Endangered Tristan albatross. Sadly, non-native invasive mice were introduced by passing sealers during the 1800s. Today, we know the invasive mice kill over 600,000 chicks each and every year. If nothing is done, we will lose some of these iconic seafarers forever.

 

The RSPB and our partners are working hard to restore Gough Island, as part of the Gough Island Restoration Programme. As the RSPB prepares to restore Gough Island, Keith Springer, our eradication expert, embarks on his first visit to the island. Here is his story so far.

 

If you would like to learn more about the Gough Island Restoration Programme, please follow this link: http://www.rspb.org.uk/goughisland

 

If you would like to support our efforts to save this important seabird island and prevent the deaths of over 600,000 seabird chicks a year, please follow this link to our donation page: https://www.rspb.org.uk/applications/Donations/single/index.aspx?dt=MDNGOU0024

For nearly a year now I’ve been working for RSPB as the Operations Advisor for the Gough Island Restoration Programme (http://www.rspb.org.uk/whatwedo/projects/details.aspx?id=419512). I’ve been involved in this sort of work for several years now, with fingers in the pie of pest eradications on a number of islands – mostly sub-Antarctic ones such as Macquarie Island and South Georgia.

  Keith Springer

 

With Gough, I’ve mostly been involved working on the procurement aspects of bait, shipping and helicopters. At its simplest, these three components together with staff to operate them all are the core means of delivering the Gough Island restoration programme. This is based on the eradication of invasive house mice by distributing toxic baits from buckets slung under a helicopter – a technique known simply as aerial baiting.

It sounds easy if you say it quickly. And in a way the method is pretty straightforward. Behind it all though, and what makes it work, is a lot of very detailed planning and the adaptation of some pretty neat technology – more on that another time. Firstly, the preparation of applications for various relevant approvals to do the work must be done. Secondly, operational planning needs to be robust, and based on undertaking actions and using methodologies that maximise the chance of successful eradication. Finally, there is an enormous amount of detailed logistical planning to be done. Gough is around 2,800 km from Cape Town, the closest city, so once on the island you can’t go back if you forget anything. Everything down to the last shackle, tent peg and drum of fuel has to be thought through and bought as the whole operation depends on having the right gear to do the job, plus of course enough spares for unforeseen events. It is this level of detailed planning and procurement that takes much of the time.

Anyway, now it is time to go out and take a look at the island first hand, to get a feel for the terrain and the weather, the vegetation and the infrastructure there (there is a small base operated by the South African Weather Service, apart from that – nothing.) Seeing it first hand is invaluable really, as the impressions gained will help inform much of the detail as planning progresses.

I’m really looking forward to the chance to visit the island, although for rather sad reasons. Gough holds a very special place in invasive rodent biology. It was here in 2004 that Ross Wanless and Andrea Angel first documented evidence of what no-one had previously considered possible – that tiny mice were capable of attacking seabird chicks weighing several kilograms and causing their deaths. When the chicks in question were the young of the Critically Endangered Tristan albatross that certainly grabbed people’s attention, especially given that the attacks filmed showed the mice eating the chicks alive. Twelve years down the track, we not only know that mice are capable of keeping Tristan albatross breeding success as low as an unsustainable 10%, but that most other burrow-nesting seabirds are equally susceptible to similar attacks. All this means that many bird species on Gough Island are doomed to a precarious existence – if any existence at all – if predation by mice cannot be stopped.

 Mice attacking albatross chick (Credit: Ben Dilley)

On other islands where I’ve worked it has usually been rats that cause this sort of ecological carnage, and rats are well known for removing entire species off islands over the long term by eating eggs and chicks to the point where populations can’t sustain themselves. Mice are gaining recognition as being capable of similar impacts though, and all that started – or at least became known - on Gough Island. Evidence of similar predatory behaviour has also been documented on sub-Antarctic Marion Island too – a South African territory in the southern Indian Ocean. I’ve just come from spending the winter on Antipodes Island, 760 km from New Zealand, as part of the Million Dollar Mouse programme (http://milliondollarmouse.org.nz/) which is another project designed to eradicate mice from an island. Like Gough and Marion, mice are the only invasive mammal species present on the Antipodes. 

Many people think – or assume – that surely it must be impossible to remove a tiny animal like a mouse from an island. We’re not talking getting most of them, or lowering the population a bit – to be successful in eradication means getting every last individual. Let me be clear – there are enormous challenges in doing this, but they are not insurmountable. Rodents have been eradicated from over 400 islands around the world. It’s not well known work as most of the islands are uninhabited and far from centres of population, but it is a fairly routine conservation tool these days, so the ‘how to’ aspect is pretty well established. And let’s face it; if we weren’t up for the challenge, there is no doubt that species – including endemic species – will go extinct on Gough Island.

 SS Agulhas II (Credit: Peter Ryan)

So for now it is time to head off – we are travelling on the South African Icebreaker SA Agulhas II from Cape Town and heading first to Tristan da Cunha. We drop some passengers there and then continue to Gough Island on the annual relief voyage. The team that have been there for a year will come home, and we will leave behind their replacements for the year to come. I’m keen to have a look at the infrastructure in particular, as an aerial baiting operation doesn’t travel lightly, and we need a lot of space to put everything! Along the way we should see an array of sea birds – albatross, giant petrels, shearwaters and prions - as well as some of the other petrel species that ply their trade around the world’s oceans. It’s about 10 days before we arrive at Gough, and once there the typical frenzy of a relief voyage will ensue. All the supplies and equipment needed by the in-going team need to be flown ashore, and those there for the brief period of the change-over need to get stuck into their work programmes. It’ll be a hectic and exciting time for all concerned!

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