Study of puffin feeding habits finds that they may struggle to adapt to changes in their environment

New research exploring the feeding grounds of puffins and razorbills has discovered that puffins in Britain may find it difficult to adapt to changes in their feeding grounds based in the North Sea. This has led to scientists advocating the importance of marine protection areas (MPAs) to support the protection of the country’s most popular seabirds. Britain’s coasts are home to globally important populations of many species of seabird, but they face many challenges as their established habitats change.

Research into the feeding habits and distribution of Atlantic puffins and razorbills on the Isle of May National Nature Reserve, based in southeast Scotland was undertaken by scientists at the University of Southampton and the Centre for Ecology & Hydrology.

The seabirds’ over-winter feeding habits were studied and they found that during the 2014 to 2015 winter, when conditions were good, both species fed close to their breeding colony eating mostly lipid-rich fish such as sandeels. However during the 2007 to 2008 winter, conditions were not as good and the small fish populations were mainly located further out in the southern North Sea. Whilst the razorbills flew further away from the breeding colony in order to maintain their healthy diet, the puffins remained closer in, eating a poorer quality diet of crustacea, polychaete worms and snake pipefish. The study showed that fewer birds survived to return to the colony in the spring of 2008 compared to 2015, with puffins being significantly affected compared with razorbills.

To identify the birds’ most likely foraging locations and position in the food chain, the team used small geolocation loggers attached to leg rings and a map developed by the University of Southampton based on the chemicals found in jellyfish in UK waters. These chemicals vary across marine space due to differences in the marine environment’s chemistry, biology and physical processes and are transferred up the food chain to the seabirds. Therefore, the scientists were able to measure the natural chemical signals within feather samples and match them to the jellyfish map.

Dr Katie St John Glew, postdoctoral researcher at the University of Southampton said: “We still know very little about where some of our commonest seabirds feed and what they eat outside the breeding season.  To protect seabird populations within UK waters and across the globe, marine spatial plans need to consider not only where seabirds spend the summer but also where they are in the winter months.  This information is critical for assessing vulnerabilities of seabird species to climatic and environmental change and for designing effective management strategies for these species.”

“This combined technique allows us to better refine where different populations are feeding during vulnerable periods of the winter. By measuring the stable isotopes in a bird’s feathers, we not only get information on where it was feeding, but also, what it ate.”

Furthermore, the methods used in this research are not only important for seabird conservation but can also be used to provide diet, movement and point of origin information on a wide range of marine animals.

“Numbers of many seabird species are already declining. Given the increasing threats from climate change and human activities such as fishing, microplastics and offshore windfarms, identifying ways to protect and conserve seabirds when they are at sea are urgently needed” said Professor Sarah Wanless from the Centre for Ecology & Hydrology. 

Marine Protected Areas (MPAs) are currently considered best practise in seabird conservation. However, current MPAs are mainly designed to protect significant foraging areas during the breeding season when birds’ feeding options are restricted by the need to return to the nest to incubate their eggs or feed their offspring. Currently, very few MPAs consider winter foraging locations and how these critical areas can change each year.

This study published in the journal “Movement Ecology” was funded by a NERC SPITFIRE PhD award, NERC UK National Capability grant, NERC/Defra Marine Ecosystems Research Programme, JNCC and the Norwegian SEATRACK programme.