Puffins opt for a lower quality diet when conditions get tough

Nov. 4 (UPI) — Instead of venturing farther from their breeding grounds in search of a nutritious meal, puffins facing harsh weather conditions prefer to snack on less healthy food items close to home.

Researchers used geolocation loggers to track the movements and dietary habits of Atlantic puffins and razorbills living on the Isle of May National Nature Reserve, off the southeast coast of Scotland.

During the winter of 2014 and 2015, conditions were ideal. Both seabirds mostly ate sandeels of lipid-rich fish. But when conditions worsened in 2007 an 2008, the razorbills ventured farther from their breeding sites to find sandeels, while puffins settled for less nutritious snacks — crustacea, polychaete worms and snake pipefish. Fewer adults returned to the breeding grounds in the year following the harsh winter.

In addition to geotagging the birds, scientists also collected feather samples and tested for chemicals found in jellyfish, which accumulate as it moves up the food chain. Scientists compared the chemical findings with a jellyfish distribution map.

“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 U.K. 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,” Katie St. John Glew, postdoctoral researcher at the University of Southampton in Britain, said in a news release. “This information is critical for assessing vulnerabilities of seabird species to climatic and environmental change and for designing effective management strategies for these species.”

Authors of the new study, published recently in the journal Movement Ecology, suggest their analysis methods could be used to track where and what other marine species are eating. Researchers hope the study will inform conservation efforts for the puffin and other vulnerable seabirds.

“Numbers of many seabird species are already declining,” said Sarah Wanless, an ecology professor at Southampton. “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.”