Thursday 18th May comments: This year on the Isle of May National Nature Reserve a join venture between SNH and CEH is being carried out on our small breeding population of Great Black-backed Gulls. Sophie Bennett takes up the story:
“Alongside the monitoring of other nesting seabirds on the island, one of the more gruesome pieces of research this year is looking at the predation of Puffins by Great Black-backed Gulls. While our puffins don’t have to worry about terrestrial predators like foxes or rats attacking them and their chicks they must keep a wary eye on the Great Black-backed Gulls nesting near their burrows. These gulls will take both fully-grown puffins and pufflings as prey, turning them inside-out before enjoying their colourful dinner!
In recent years the number of nesting Great black-backs has increased on the island, with 2017 shaping up to be another record year. As the gulls increase in number it is important to understand whether they are having a significant impact on the May’s puffin population. In order to determine which individuals are responsible for the predation, pairs that have been seen to take puffins are being caught and given a colour ring with a unique identification number. These pairs will then be monitored throughout the season to try and quantify how many gulls are specialising in this feeding behaviour and just how many puffins they are predating.
Not all Great black-backs take puffins however and those that do will be specialising in this feeding strategy. The majority of individuals instead will predominately be feeding on crustaceans, fish and other prey items. Gulls are often publicly portrayed as terrors of the skies, but these impressive seabirds are just making the most of an abundant food source to try and raise their chicks. With Great and Lesser Black-backs currently being amber-listed birds of conservation concern and Herring Gulls being red-listed, we are very fortunate to have healthy populations of these three species as part of our incredible seabird colony on the Isle of May.