Tuesday 23 August 2022

OxNav update: the secret lives of Manxies

Hey everyone!

Today’s blog has been written by OxNav, who are a group of student researchers based on Skomer, studying the ecology and navigational strategies of Skomer’s hidden gems, the Manx shearwaters! 

For those who may be unfamiliar with Manx shearwaters, or Manxies as we fondly call them, they are a species of Procellariform seabird which spend the majority of their lives out at sea, but return to burrows on islands around the UK, such as Skomer, during their summer breeding season to reunite with partners, lay eggs, and raise their chicks.

Skomer Island is home to the world’s largest colony of Manxies, an impressive 350,000 pairs, which makes up 40% of the world’s population! Here at OxNav we study breeding pairs in one of the densest parts of the island, North Haven. For those of you who have visited Skomer, you have likely gazed across our study colony without realising, we face out of North Haven bay, where the boats land, and our colony spans the hills all around the warden’s house, with hundreds of burrows marked and hatched for easy access into the nesting chamber.

Top: black and white photograph of a Manx shearwater at night. Bottom: two well-wrapped up people lying on the ground with their arms down burrows, surrounded by white and green burrow marker posts
Above: An adult Manx shearwater sat on the surface at night.  Below: Lewis and trusty friend Alice checking study burrows for the arrival of an egg.

This year, we arrived on Skomer with the Manxies, all the way back in the beginning of April, when the first adults returned from their grand migration to Argentina to reunite with their partners. However, getting here as early as we did this year revealed that perhaps these pair-bonded seabirds aren’t as loyal as we once thought they were! We found that many birds would spend the night cwtched up in a burrow with a bird other than their usual partner, only to then go back and recouple with said partner later in the season, I guess the grass wasn’t greener in the other burrow for these birds! But this posed an interesting theory, how can a male ensure that he is the father of the chick he raises? Do perhaps males with a greater drive to defend their burrows (and in-turn their partner) have a greater chance of being the biological father? Sounds to us like a job for Jeremy Kyle…

A black and white photo taken from a burrow camera video in an artificial burrow. Two Manx shearwaters are in the breeding chamber, the head of the left hand bird resting on the back of the right hand bird.
A breeding pair of Manx shearwaters spending the night together in their burrow.

Once these dramatic revelations had passed and eggs had been laid, we turned our attention to our incubation tracking campaign! We attached small GPS loggers weighing only 10g to the backs of adult Manxies (picture a little computerised backpack) to track their movements during their at-sea foraging trips. These excursions can last over 10 days, with the birds covering incredible distances in search of food to fuel their next stint of incubating the egg! From these GPS tracks, we can uncover so much about these speedy seabirds: where they go to forage, when and how they make the decision to return home, how they do this with such accuracy, and how all of these wonders vary between individuals.

A map of the UK and Ireland, with different coloured lines showing the migration of different incubating Manx shearwaters. Most foraged within the Irish sea, but some headed further North, with one bird going beyond St Kilda into the Atlantic Ocean
GPS tracks from incubating Manx shearwaters. Each colour shows a different bird, with one heading far North out into the Atlantic Ocean!

Now, the moment you’ve all been waiting for… fluffy chicks! From lay to hatch, the parents will incubate an egg for around 51 days, before a bundle of cuteness and downy feathers cracks its way out of the small, white egg. Here at OxNav we are lucky enough to monitor a subset of our colony’s chicks, weighing them every day to gain insight into general colony productivity, potentially revealing seasonal variations in food availability, or perhaps how well the parents are performing in their baby-feeding strategies. Of course this chick monitoring has great scientific value, but personally we love the opportunity to watch these fluffy chicks grow and develop, from a small 50g peeping nugget, to a 650g sacks of flapping wings and teenage angst.

Pictured below is our personal favourite, Megan thee Shearwater, affectionately named after the hip-hop sensation, Megan thee Stallion, representing strong female shearwaters, and all the trouble they go through in producing and laying the egg, you go girls!

From left to right, we see our lovely long-term volunteers: Eve, Kelda, and Lira & Anna, helping to weigh Megan as she grew throughout the season!

In the past few months, when not cuddling chicks (for science of course), we have been deploying more GPS devices to gain insight into their shorter, more frequent chick-rearing foraging trips. This year we have synchronised deployments across the islands of Skomer, Skokholm, and Ramsey, to see if these colonies overlap in their foraging grounds, or perhaps all occupy separate areas! We also piloted a future study for one of our new PhD students, Lewis (that’s me, hello!), where we displaced GPS-wielding adults to other locations around the island, such as the Mew Stone and Garland Stone, to investigate whether their short-scale navigation is as impressive as in their long-range movements. Here's a little sneak peek for you… it’s looking like the answer is yes! We had birds which seemed to understand their release location very well, knowing the optimal route around the island (since they prefer not to fly over land), and returning to the colony in less than three minutes, now that’s a bird with a built in SatNav if I’ve ever seen one!

A photograph of a hand holding out a Manx shearwater. The photographer is using a red light torch so the picture is all in red and black, except for a bright blue light on the back of the bird, which is the GPS flashing.

A Manx shearwater mid take-off during one of the displacement studies. You can see the GPS flashing as the bird is released.

The chicks will now be fed and raised until September, when they will depart for their winter grounds in the seas off Argentina! Our masters student, Alana, has spent many of her evenings sea-watching at Garland stone, recording information on the rafting behaviour of Manx shearwaters, seeing how long they sit on the water, in what numbers, and if the locations of these rafts is consistent over time! This has been a great excuse to head out of North Haven, picnic in hand, to watch the sunset and take in all the other nature that Skomer has to offer, even if Manxies are our particular favourites.

We hope you’ve enjoyed reading about our work! We love chatting about Manxies (if you couldn’t tell) so drop the team a message through these accounts if we’ve piqued your interest: Instagram - @Lewisthezoologist, Twitter - @LFisherReeves

Lewis & Alana

A picture of three smiling people against a background of a sunset above the sea.

Team Chick-rearing 2022! Alana, Trina, and Lewis, enjoying the sunset together.

Just to note: With the increasing risk of highly pathogenic avian influenza (HPAI) to our seabirds, it’s worth mentioning that all handling pictured was carried out in the months prior to the rising cases. OxNav and the Wildlife Trust of South and West Wales have been closely monitoring the situation and abiding by guidance from leading bodies. Unfortunately, all bird handling on Skomer has now been suspended until further notice. 

Tuesday 2 August 2022

Introducing Anna and Lira: our new LTVs

Hello everyone and welcome to our first blog! We are the new LTVs (long-term volunteers) Anna and Lira and we are super excited to keep you updated about everything we get up to on the island!

Here we are on our first early morning gas run to Martins Haven, Anna (left) and Lira (right).

We both arrived early July and will be staying on the island till October - so we will be involved in lots of different tasks, from daily welcome talks to helping out with research around the island. Can’t wait to keep you all updated 😊


Hi everyone, my name's Lira and I’ll tell you a little bit more about me and how I’ve ended up on Skomer Island, it’s been a complete rollercoaster! I’m the first generation in my family to be born in the UK as we are originally from Latin America (Colombia and Chile) but my parents moved to London as children and have lived in London ever since! Against the odds, I have always felt a huge sense of connection to nature and from a young age I knew I wanted to work with wildlife. 

 I enjoy birding in my free time.

Growing up, I never really saw people like myself in green spaces and definitely didn’t see anyone who looked or sounded like me on the nature programmes which was a huge challenge growing up as someone wanting to pursue a career in wildlife conservation. Living in London also provided some challenges as there aren’t many opportunities for people seeking experience in conservation, and getting an office job in the heart of London is what most people in the city aspire to do (and what is actually encouraged in schools). I decided I would stick with my dreams of working in the field and although I was told that becoming a vet is the best option for an animal lover in London, I went to study Zoology at the University of Reading. 

After graduating, unfortunately I started to believe that maybe conservation wasn’t for me. I had the passion but I just couldn’t get my foot in the door with experience. Volunteering away from home wasn’t an option either as I just couldn’t afford it after university.  I simply gave up for about a year and got a ‘normal’ 9-5 job. Although the pandemic was a scary and lonely time, it really put things into perspective for me and reminded me what was truly important to me. Wildlife. Nothing makes me feel more whole and happier than wildlife. I spent the months of lockdown applying for conservation roles and creating wildlife opportunities for myself. 

Me giving a welcome talk to visitors arriving on the island.

A few months into lockdown I got offered an opportunity with BirdLife Malta as a nature reserves assistant and ringing assistant. I couldn’t believe it! Since then, I’ve also completed a traineeship with the London Wildlife Trust and now I am at Skomer! Since arriving, I’ve held welcome talks, helped with habitat management, assisted in bird ringing and much more! I have encountered so much wildlife already and feel super lucky to have seen the last of the puffins before they head out to sea. Everyone, from the staff to the volunteers, have been incredibly welcoming and have really made me feel at home. Very important when living on such a small island! With every day being so different to the last, I should have experienced tons by my next blog and can’t wait to tell you all about it! 

Thank you for reading and stay tuned! Love lira x


Hello! I’m Anna. I’m really excited to be a long-term volunteer on Skomer. I have been really enjoying my time here so far, keeping busy with welcome talks, brush cutting, maintenance tasks and lots of refreshing evening swims in North Haven (it’s been a very hot first few weeks!). I’ve also been lucky enough to help out with some of the ringing and weighing of the island’s seabirds, including Gulls, Manx Shearwater, and my new favourite – the tiny Storm Petrels! I love how each day is so varied here. It’s also great meeting so many lovely people; Skomer is a busy place as weekly volunteers and researchers come and go.

 Enjoying a Skomer sunset with the puffins.

Before coming to Skomer in July I had never been before and was really excited to see what island life was really like. This June, I completed my undergraduate Zoology degree at the University of Sheffield. I chose to study Zoology after hearing that such a course existed whilst volunteering at the Birdfair in Rutland during my summer holidays. I have always enjoyed watching and learning all about wildlife but going along to Birdfair really opened up the world of conservation to me and I realised it was something I could make a career out of. During uni I put this passion for nature into volunteering with the conservation society at weekends. 

After my 2nd year of uni I did a year long placement at the Wildfowl and Wetlands Trust in Washington (North East England). During this year I learnt so much about what it takes to manage a nature reserve from practical habitat management and species monitoring to visitor engagement, I was in my element! My placement also allowed me to really develop my wildlife identification skills and I started to really enjoy identifying plants and wildflowers – something I will continue to work on here on Skomer. 

In my spare time I love to go off on camping adventures.

Whilst at uni and back home (North Yorkshire) I spend much of my free time out and about walking, quite often with my life packed into my backpack, off on yet another camping adventure!

Spending my summer on Skomer is a dream come true and I can’t wait to get stuck into even more over the coming months. I look forward to updating the blog!

Anna 😊