Today’s puffin blog has been written by Project Officer Chantal Macleod-Nolan on how food is changing in a warming ocean

Atlantic Puffins with their colourful bill and inquisitive nature are quite the charismatic seabird. They are also site faithful, returning to their burrows year after year. In previous years, I’ve had the pleasure of visiting islands such as the Shiants and the Farnes where it’s fantastic to watch the seabird spectacle including puffins returning with fish, occasionally dodging opportunistic gulls, and diving into the burrows to feed their young pufflings.

Puffin heading to its burrow © Chantal Macleod-Nolan

Pufflings are fed by both parents and fledge between 34 and 60 days depending on the area and year. During this time, they’re at their most vulnerable and chick survival can be greatly affected in times of food shortages.

An important fish species for puffins are sandeels, particularly Ammodytes marinus. This small eel-like fish is easy to ingest by small seabird chicks, and protein packed for a high nutritional value. However, in the last few decades, the abundance of sandeels has decreased in northern waters which has had cascading effects on their predators.

In flight © Chantal Macleod-Nolan

Scientists have been investigating the trophic links of sandeel and there is compelling evidence that they are becoming severely depleted, and that rising sea temperatures are to blame. Since the mid-1980s, the abundance of their own food source, a cold-water copepod Calanus finmarchicus has declined in certain areas of the North Sea. Although a different copepod (Calanus helgolandicus) has increased instead, as the spawning time does not overlap with the early life stage of sandeels, it means these tiny crustaceans are not suitable an alternative prey source.

Sandeels have strict habitat and environmental preferences, favouring shallow inshore waters, which means that despite the diminishing food resources they are unlikely to shift their distribution. Changes in habitat are having a detrimental impact to their own body condition. This means that not only are there fewer sandeels available to seabirds, but the size and nutritional value of the individual sandeels are also shrinking.

Other birds are also affected; Arctic terns and black-legged kittiwakes can’t dive as deep as puffins and so have access to an even less diverse range of prey. All three species of sandeel-dependent seabirds have now been red or amber-listed under the UK’s Birds of Conservation Concern, and puffin and kittiwake are listed as globally vulnerable to extinction by IUCN.

As a result, the adults are having to travel further to find suitable food, in order to feed their starving chicks. On Shetland, we found that some puffins had to make round trips of 250km, ten times further than normal, and even then, were often bringing back much smaller sandeels compared with those on main­land colonies further south.

Photos, such as these, can help us build a picture of what food is available to puffins © Chantal Macleod-Nolan

Through provisioning monitoring, scientists record the changes in seabird diet and how they are faring with climate change and the associated sea warming. There are difference methods of monitoring these seabirds and their diet and with your help we’re able to get an insight.

Seabirds are a great indicator of the ocean’s health and we can use your photographs to identify the different types of fish that puffins are eating including, whether they are nutritional in value. So, if you want to get involved, please send through any photograph that you’ve taken of puffins with food in their bills (be it from any year and any colony). To find out more, visit www.rspb.org.uk/projectpuffin

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