St Kilda diaries with Cal Major

Transcript

One speaker: Cal Major

One of my roles while I'm here on St Kilda is in biosecurity monitoring.
Now, that might not sound like the most exciting job, but it is one of the most important aspects to keeping St Kilda and its wildlife safe.
St Kilda is way out into the Atlantic Ocean, and so it's been protected from invasive species for centuries -- things like rats and hedgehogs and mink.
Rats have never been recorded here on St Kilda, and the introduction of them would be catastrophic for the ground-nesting birds.
Now that St Kilda is more connected to the outside world by the boats that are arriving every week, one of my roles is making sure that rats cannot come off those boats onto the island. There are several ways in which I do this.

This is the Feather Store where the St Kildans would have stored their feathers, and one of the bits of advice I was given when I first started this role was to think like a rat!
So, we're placing these bait boxes in places where rodents would like to hang out or hide.
Obviously around walls and in buildings is one of their favourite hang-outs.
These bait boxes are filled with these little blocks of harmless flavoured wax, which are meant to be enticing for rodents, so that they come up and have a nibble.
And then we can go back and check them and see what the bite marks -- if any -- look like, to check that it is just mice and not rats.
There are loads of St Kilda mice on the island here, and they are regularly having a little nibble; it's doing them no harm at all.
But what we want to make sure is that we're not getting teeth marks from rats, because if we do, there's a rat on the island -- and that's trouble.

There are two main types of boat that would arrive here on the island.
First are tourist boats, which moor out in the bay and then bring their passengers to this jetty.
And the second is a big supply ship, which brings food and equipment to the people working here on the island.
Now, when that supply ship's in, its ramp comes straight down onto the beach.
There's a much higher chance of invasive species, like rats and hedgehog and mink, getting onto the island that way.
So when it's here, I have to sit and watch the ramp the entire time it's down on the island to make sure that nothing gets off.

These are the live traps that we put out for a few days after the supply ship's been in.
We put a bit of peanut butter and porridge inside to try and entice any rodents in.
I mean, if I was a rat and I'd just been a stowaway on a ship for a few days, I'd probably be interested in that too!
We tend to find quite a lot of St Kildan mice in the traps because there's loads of them here in the village.
As soon as we find a mouse, we let it out; no harm done.
The idea is just in case something slips through the net, we find it in the trap and it doesn't escape onto the rest of the island.
There are 10 of these live traps set around the village, and bait boxes spread across the entire archipelago.
If a rat is found, there's an incursion response which can be rolled out immediately.
Altogether that forms a really good, cohesive plan to keep these islands safe from invasive creatures.

It's not just invasive animals that are a threat to the wildlife here, but also pathogens such as bacteria, fungi and viruses.
All visitors are required to walk through this mat here that's impregnated with disinfectant before they're allowed onto the island.
If you're planning a boat trip to St Kilda, you can do your bit for biosecurity by following the Check, Clean, Close rule.
Please check your bag and clothes for pests; clean your boots or shoes with disinfectant; and tightly close any food containers, since they can attract stowaways onto boats or into bags.
Thank you!

Transcript

Two speakers: Cal Major and Craig Nisbet

Cal
One of the projects I'm most excited to get involved with here is with the great skua, or, as they're known by their Shetland name: the bonxies.
These are an amazing seabird, one of the biggest, and they predate on other birds.
Unfortunately, they were one of the hardest hit by avian flu.

Craig
In 2019 the census revealed 183 breeding pairs of great skua; this year, that number has declined to around 50 pairs remaining.
When I started, I was very excited about working with the seabird assemblage on St Kilda, but particularly with great skuas.
In 2021 I found my first dead great skua around about early July; it wasn't until I found a few more that the alarm bells started ringing.
By the end of that season, we had reported 66 dead adults that had been found on the island.
The following year, things got a lot worse.
That was hard; that was really hard.
I've been working with seabirds for over 10 years on various islands, and I've never had to deal with that level of mortality for such an extended period over two seasons.
It felt in 2022 like a very big part of my job was overseeing the demise of one of our most fantastic seabird species that we have breeding on the island.

Cal
Two-thirds of the global population of great skua nest in Scotland, and since 2021, avian influenza wiped out three-quarters of them.
In 2024 on St Kilda there was one confirmed case of avian flu in a great skua.

The research work here with great skua has been in two stages.
The first has been mapping where their territories and their nests are around the island.
And the second is what we're doing today, which is going up the hills, catching them, ringing them and taking samples from them, so that we can see what their response to avian flu has been.
This is so exciting! It's not every day you get to go and be this up close and personal with a great skua.
It feels like a huge privilege to be a part of it.
We've got some big hills to climb so we better get going.

[whispers] above that cleit there!

[whispers] So we found a nest with two eggs.
We've removed the eggs from the nest and put fake eggs in instead, which I've warmed up underneath my armpits to make them as realistic as possible.
The idea is that the bonxie who's flying around -- she knows we're here -- comes back and sits on these fake eggs.
We can set the trap; we can catch her without any damage to the egg or to her.
In the meantime, the real eggs are in insulated tubs so that they don't get cold; they're protected basically.
And we can just put them straight back onto the nest.
We've got really strict time frames to do this in, so the disturbance is minimal, so that we know that we're not damaging the eggs or causing too much distress to the bird.

Can I get your bag out? And I'll start getting things ready.

Hello love.

So, these colour rings -- they're applied to the bird's leg and it means that we can identify individual birds, follow their life and their stories over many years.
You can actually see them through binoculars, so we don't have to catch the birds to be able to identify them.
It's a really exciting way of being able to see what happens to that bird: how long it lives, whether it has chicks, whether it keeps coming back to St Kilda, or ends up somewhere else in the world completely.
It's all about telling these individual bird stories.

Have a little look at that, Liz. That looks great, yeah, perfect.

[whispers] Well done!

We've had one successful nest, which feels like such a massive relief, after all the work and time we've put into this project.
And we just found another nest with eggs, so hopefully this one goes just as smoothly.

Craig
1.65 ...

Cal
[whispers] Ok, that's the best I can do with that.

This research has never been more important.
During my time on St Kilda, I developed a real fondness for great skua.
After a few very tough years, I'm really rooting for them and hoping that the beautiful sight of their chicks hatching here on St Kilda is the start of their population's rebounding, retaining their global stronghold in the islands of Scotland.

Transcript

Three speakers: Cal Major, James Crymble and Liz Morgan

Cal
Today, we're over on the wilder side of Hirta, the main island here in St Kilda, and we're on our way to go and catch some puffins in a kind of net called a mist net.
We've got two seabird ecologists and myself as a veterinarian, and I'm really excited to be able to use my skills to take some samples from these birds so that we can better understand their response to the avian flu viruses.
This feels like a real adventure! It's super wild out here and I am very excited to go to one of the remotest parts of the island and one of its biggest puffin colonies.

I never get tired of seeing puffins, especially in the numbers that they are here.
Oh, it's amazing!

St Kilda has the UK's largest puffin colony.
These are notoriously difficult birds to accurately count, but the best available surveying methods show between 80,000 and 160,000 breeding pairs.

Is this a fairly standard way to catch puffins?

James
Yeah, it absolutely is. Mist nets are used by a lot of ornithologists.
It's a really low-impact method to catch birds.
The other option would be to take them out the nest, which is obviously a lot of disturbance, a lot of disruption, so this way at least we're getting a good, almost randomised sample of what's flying around.

355. 355?

Liz
We've got these little metal rings.
They've got a unique code on so we can identify them, and then follow their life history.
For this project, we know we've sampled this bird so we don't need to sample him again.

Cal
[whispers] Yeah, close properly ... Hey, brood patch!

James
There we go. It's starting to feather over, Liz, so partially open.
This is the patch of skin that has a lot of blood vessels in it.
It's called the brood patch and this is what the bird will use to incubate her egg, keep it nice and warm.

You do a very good job at finding brood patches.

Cal
You can actually use the number of grooves on the colourful part of a puffin's bill to work out roughly how old it is.
The more grooves, the older the bird, with puffins breeding at 3--4 years old, with at least two grooves.
This is another useful metric for us to record.

Stay still! Very well behaved puffin.

It's worth pointing out that we are doing this work under a licence, under very strict conditions, minimal handling time.
We've all been through extra training; these guys are experts in this kind of thing.
They handle seabirds all the time.
It's really strictly controlled to make it as minimally invasive for these little animals as possible.
It's really good to be able to do something with this bunch of experts, and with the skills that I have as well, to learn more about the threats that these seabirds face, and then to be able to release them back into the crowd and see them swarming around here.
This mass of puffins thriving on this island is really great.
That's really good, isn't it?

[whispers] That's us done for the night; we've caught 10 birds.
It's been a really fantastic evening, and now we're all going to head back to our beds.
We'll probably come back and do this a few more times over the season, but for tonight we're finished.

Transcript

Two speakers: Cal Major and Craig Nisbet

Cal
I think there's something really poetic about the way that the relationship between humans and seabirds here on St Kilda has changed.
From humans harvesting seabirds to eat them, to there now being humans living on St Kilda to protect and understand the seabirds better.
Even to the way that the seabirds have now reclaimed some of the man-made structures, such as the walls and the cleits, which would have been used to store them in, as their nesting sites.

There are many ways that the National Trust for Scotland's staff and volunteers care for the seabirds here on St Kilda.
One really important task is monitoring their numbers and breeding productivity, and I was really interested to find out how those have changed over the decades.
I went to see Craig who was conducting one of his productivity surveys of nesting fulmar.
So, what are you finding from your productivity studies?

Craig
In our most recent census effort last year, that indicated that fulmars had declined by about two thirds in a 24-year window.
Fulmars are very long-lived seabirds.
They can cope with some years of lower breeding success, but sustained low breeding success will lead to population declines at a colony level.

Cal
The exact cause of these declines is not fully known, but there are many factors that are thought to contribute to the complex picture, including changes in food availability as a result of climate change and certain fishing practices.Seabirds at the top of the marine food chain are a biological indicator of the health of the ocean. They are our connection to what's out of sight below the surface. Changes underwater are far harder to see but changes in seabird numbers can indicate changes in the overall health of our blue planet.

How do you see the contrast between your relationship and your work with the seabirds now, and the relationship between the seabirds and the St Kildans who relied on them all those years ago?

Craig
It's often on my mind when I'm monitoring these birds and counting them.
The St Kildans 100 years or more before me would have been up on these cliffs and looking down trying to figure out where these birds are, in order to harvest them.
I wouldn't be at all surprised to think that the St Kildans loved these birds every bit as much as we did, but obviously for slightly different reasons.
And it's what makes the islands so special.
It always has been a seabird island -- a seabird archipelago.
We get that question quite a lot: what impact did the St Kildans have on the seabird population?
What we do know is the population has been declining in spite of harvesting not being an issue for well over 100 years.
I would say that climate change has a much bigger impact than a small community of people living on this island ever did.

Cal
One of the things that really strikes me about St Kilda is the change that this island chain has gone through over the decades and the centuries.
St Kilda might be a completely remote place but it is no longer somewhere that is cut off from the impact of the outside world.
The National Trust for Scotland's new Plan for Nature will help guide their work to better understand and protect the seabirds in their care.
Within that plan is a project to specifically investigate the causes of decline in St Kilda's fulmar population, enabling the rangers here -- St Kilda's modern-day custodians -- to best support these incredible islands and their seabirds in the decades to come.