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Vanessa Amaral-Rogers

Today's blog is by one of our newest puffineers, Will Bevan.

A couple of months ago I joined the RSPB's Project Puffin team as a volunteer. Originating in 2017, the project set out to discover how puffin diet was changing at colonies around the UK, and whether this was linked to worrying declines of this iconic seabird. A great example of citizen science in action, it is beginning to reveal how warming oceans might be affecting the availability of their favourite prey species. In this post I delve into the threats facing puffins, as well as the essential work that the Project Puffin team is undertaking.

Is there a more iconic and instantly recognisable bird in the UK than the puffin? Their clownish looks and clumsy antics are a huge draw for tourists across the country, and provide endless entertainment for those who are lucky enough to see them. The puffins which call our shores home are Atlantic puffins (Fratercula arctica), the scientific name translating as - 'Little Brother of the Arctic' -  an endearing name given to them due to their black and white plumage resembling the robes of a friar. The other two species, the tufted puffin (Fratercula cirrhata) and the horned puffin (Fratercula corniculata) occur in the Pacific ocean, and are equally as flamboyant as their Atlantic cousins.

Though we know little of their lives at sea outside of the breeding season, every year they return to their colonies, often to the exact same burrow, and carpet the cliffs and islands of the British Isles for another summer. They are just one part of the great wildlife spectacles that are our seabird cities, and to be immersed in one of these places is a life affirming experience. The dazzling sight of thousands of birds wheeling overhead and streaming to and from the sea.

The cacophony of noise as parents and chicks call to each other, pair bonds are maintained, and rivals are seen off. The potent smell of guano combined with the salt air of the sea. They feel timeless, the same rhythms of life having been repeated for millennia, and it seems unreal that many of them could disappear within our lifetimes as current worrying trends suggest.

Seabirds are the most threatened group of birds, with almost half of all species in decline and many of them globally threatened. The threats they face are numerous, from predation at their colonies by invasive species, to overfishing, pollution and a changing climate. Puffins are no exception, with breeding failures and population declines at colonies in Norway and Iceland, and closer to home in places like Shetland and the Isle of May. Global trends are concerning enough for the Atlantic puffin to be listed as 'vulnerable' on the IUCN Red List of threatened species, which led to it being 'Red listed' in the UK, the highest level of conservation priority. In some colonies however, like those of Skomer and Skokholm on the Pembrokeshire coast of Wales, numbers are doing relatively well.

What is going on?

It is believed that the main factor responsible is changes in the availability of their favoured prey species as a result of climate change. Small, oily, highly nutritious fish called sandeels make up an extremely large part of their diet, and can sometimes be up to 90% of what the young puffins (adorably called pufflings) eat. The timing of the sandeel's lifecycle is critical for puffins to have enough food for when their chicks are developing. Warming oceans are affecting this cycle by causing sandeels to spawn later, and the plankton blooms the sandeels rely on for food to occur earlier.

This mismatch means that the sandeel larvae can't find the right types of small zooplankton prey when they hatch. The larvae grow slower and struggle to survive, meaning less of them are available for the hungry pufflings when the puffin breeding season is in full swing. Rising ocean temperatures also mean that the copepod Calanus finmarchicus, an important prey for the sandeels, is being replaced by a warmer water species, Calanus helgolandicus, which is less nutritious. This means smaller, less nutritious sandeels for the puffins.

Sandeels also depend on sand which they need to burrow in at night and during the winter, as well as to lay their eggs on. They are therefore limited as to where they can live and cannot shift away from warmer waters as other species might. Climate change might also be influencing ocean currents, affecting how the larvae are dispersed. This could be bad news for relatively isolated areas of sandeel habitat which rely on currents flowing their way in order to recruit more sandeels into the population.

There are multiple, complex forces at work, with serious consequences for puffins. What's clear is that around some colonies there are simply not enough sandeels, and those present are not large or nutritious enough to feed the hungry chicks. This means that the adults need to travel further to find food and bring it back, which costs them more and more energy, and ultimately the adults have to choose self preservation over continuing to support their chicks.

In colonies where puffins are doing well, it might be that these effects aren't being felt yet, with plenty of sandeels and other preferred prey still within a reasonable distance to ensure the chicks survive. There are other factors which might be contributing to their declines as well, such as prey being depleted by commercial fisheries or an increase in extreme weather which causes massive 'wrecks' of puffins at sea. What is clear is that we don't know enough to be sure as puffins are notoriously difficult to monitor. They spend much of their lives at sea, and often breed in inaccessible locations. So how do we know what they are eating?

Bring on the 'Puffarazzi'

What more classic an image is there than of a puffin with a beak stuffed full of fish, and what better a record of the prey species that bird was bringing back to its chick? Thinking that this huge potential resource had gone untapped, in 2017 the RSPB's Project Puffin led by Dr. Ellie Owen ran a citizen science project (more about citizen science HERE) enlisting members of the public - the puffarazzos - to submit their photos of puffins with prey in their mouths, no matter what the quality of the photo. The hope was for the first time to build up a picture of how puffin diet varied across the UK, and whether this could be linked to the declines that were being observed. 

The initial response was a huge success, with 1402 photos being submitted by 602 people at around 40 colonies. From this data it could be confirmed that puffins breeding in places where they are not doing so well, like Shetland and Orkney in the northeast of Scotland, were catching smaller fish and less sandeels than those in other parts of the UK. Though puffins feed on a mixture of fish, this evidence suggests an inability to find their main prey item may be driving declines.

Being a 'Puffineer'

The project is now in its second stages, beginning in March 2019, with photos being accepted from any year in order to see how puffin diet has changed at colonies across the UK over time. In phase two, 3439 photos have been submitted by 1160 Puffarazzi members, covering 57 colonies! It is this huge dataset that I am now a part of analysing, having become a member of the team, or a 'puffineer', a couple of months ago. It is a great privilege to be a part of the project and know that my work is helping to untangle the predicament that our beloved puffins are now facing. Being able to be involved in Project Puffin, especially during this pandemic, has been a great way to connect to the islands and birds which I love from afar.

Puffins began my love of seabirds, and the time I spent with the colony on Skokholm Island (which I wrote about HERE and HERE) was a dream come true. That these birds could perhaps disappear within my lifetime is unbearable, and that future generations might not get to enjoy them as I have is something we should be determined to help prevent.

What does the work involve? 

Every couple of weeks I get an email with 100 photographs, with two weeks to analyse them and send them back. The analysing process is quite straightforward, although it can take some time to figure out what is going on in the images. Puffins can hold a surprising amount of fish in their bills thanks to some inward facing serrations on the bill, and prey can be also be layered on top of one another, making counting every single individual quite tricky.

There are four main prey types that we look for; the sandeels and their larvae, clupeids like sprat or herring, gadoids like cod or haddock, and rocklings. Puffin diet is very varied though and sometimes other things can crop up like a squid! Then we estimate the size of the fish, and note down how confident we are about our analysis. I find the work very enjoyable, and looking at these images is a fascinating insight into their lives. After days of maybe  staring at a few too many photos however, my dreams are haunted by gleaming fish eyes.

What does the future look like for puffins?

Whilst the future is uncertain at the moment, the findings from this project will hopefully provide us with vital information about how puffin diet has changed over time, and allow us to predict which colonies are likely to be affected the most by warming oceans and changing prey distribution. Though the effects of climate change are going to be hard to overcome, identifying where vulnerable colonies are located might help us to protect them in other ways. 

As a recent review suggests, if we can deal with things like overfishing, pollution, or invasive species, which we do have solutions for, populations will be more resilient in the long run. For example, if puffins are changing where they locate their food, we need to be able to protect these areas from development and fishing activities. Though there is still a lot to learn about this iconic seabird in order to ensure they are properly protected, this project is taking critical steps in the right direction.

This blog was reproduced, with thanks, from Will's blog 'Nature's Good News'.

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