We present details for the observation of an adult Atlantic Puffin Fratercula arctica collecting food in Lake Linnévatnet (78°02’N 13°48’E), the second largest freshwater lake in the Svalbard archipelago, on 11 August 2020. The bird was seen frequently diving and accumulating fish in its bill. All circumstances considered, we think the bird intended to feed a chick in the nearby Vardeborg colony. This is the first published record of a breeding Atlantic Puffin searching for food in freshwater. We discuss this finding in the light of the scarce information available on the species’ feeding ecology in high-arctic breeding areas.

Well-known to most readers of Seabird, the Atlantic Puffin Fratercula arctica (hereafter ‘Puffin’) is one of the most typical and abundant pelagic seabirds, with a total population of about 6–7 million breeding pairs spread across the North Atlantic (Harris & Wanless 2011). This charismatic auk breeds in colonies ranging from a few tens to hundreds of thousands of breeding pairs spread across the northern North Atlantic from Maine to Greenland in the west and from France to Svalbard and Franz Josef Land in the east (Harris & Wanless 2011). The species’ stronghold is the southern and eastern parts of the Norwegian Sea, where the largest colonies are found on islands in southwest Iceland, the Faroes, Scotland and along the northwestern coast of Norway.

In the chick period, breeding Puffins usually forage within 50 km of their colony, with trip length being negatively correlated to food conditions (Fayet et al. 2021). They typically raise their single chick on small (usually 5–15 cm long) schooling fish such as sandeels (Ammodytidae), Herring Clupea harengus, Sprat Sprattus sprattus and Capelin Mallotus villosus, carried crosswise in the bill in loads of around 10 (normal range 1–20) fish at a time (Harris & Wanless 2011). These forage fish are often abundant and high in lipid content in summer, but Puffins also feed on a wide variety of other prey including leaner young gadids (Gadidae) and transparent larvae of Herring as well as small crustaceans, especially when food availability is poor (e.g. Barrett et al. 1987; Anker-Nilssen et al. 2000; Fayet et al. 2021).

There are many more colonies in the Svalbard archipelago than e.g. along the Norwegian mainland (Anker-Nilssen et al. 2000) but they are small. Except for the colony on Gåsøyane (78°27’N 16°13’E), which holds about 1,000 pairs (S. Descamps, unpubl. data), all probably have less than 500 pairs (Norwegian Polar Institute (NPI) Colony Registry; SEAPOP database www.seapop.no). Although summers are milder in western Svalbard than farther east in the Barents Sea, Puffins breeding this far north are near their limits in terms of climate conditions, lack of soil suitable for nest burrows and low availability of small schooling fish, the Puffin’s preferred prey in more boreal waters. These factors help explain why the total breeding population in Svalbard is only estimated at about 10,000 pairs, spread over approximately 60 different colonies (Anker-Nilssen et al. 2000; Strøm 2006a). Most colonies are situated on the west coast of Spitsbergen, the largest island in Svalbard, where they usually breed in crevices high up in the least accessible (for Arctic Foxes Vulpes lagopus) parts of the highly eroded hillsides typical of the Svalbard landscape, but Puffins also breed in boulder screes on some of the few small islands spread along that coast (Strøm 2006a).

We thank Kjell Joar Nilssen and Martin A. Svenning for the valuable information on registrations of fish and birds in the Linné water system, and Michael P. Harris and Mark A. Newell for sharing their relevant experience from the Isle of May. Valuable input and comments were also provided by Sébastien Descamps, Hallvard Strøm and two anonymous referees.

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