Linnea is migrating south

The lesser black-backed gull, named Linnea, fitted with a satellite transmitter at Stora Karlsö earlier this season has started the migration south to the wintering quarters in Africa. The migration was initiated from a site northeast of the Island of Gotland near Finland, and suggested a very interesting northeast movement before the fast migration flight to the south along the eastern flyway across Europe and the Mediterranean was initiated. One may speculate that the marine feeding lesser black-backed gull might have followed some prey species (sprat?) to fuel before the migration was initiated. We hope that further tracking studies during the coming years will reveal whether this is a natural behaviour of the lesser black-backed gulls breeding at Stora Karlsö or if it this was the result of an exploitation of a occasional nature. Now first we are waiting for Karla to also start her migration. The destination of the two birds might however be completely different, and their plumage characteristics at capture suggested slightly different colour, with Linnea having the darkest back. More and updated information on Linneas movements are available at: http://www.seaturtle.org/

Lesser black-backed gulls Karla and Linnea – satellite tracking at Stora Karlsö

2009-06-11 Stora Karlsö

This week I have been away on field work trip to Stora Karlsö located west of the Island of Gotland in the Baltic Sea. I have been here with my collaborators Olof Olsson at Stockholm Resilience Centre and Jonas Sundberg at the Baltic Seabird Group. We have attached satellite transmitters to two female lesser black-backed gulls (Larus fuscus) breeding at the island in order to study the foraging movements and migration. The two females were captured at their breeding sites at the south coast of the island. The satellite data is currently being visualised at seaturtle.org (see link below) and you may find maps generated regularly to see the movements of the gulls.

Stora Karlsö is one of the first protected areas in the world, and is considered the second protected area after Yellowstone National Park. With its calcareous rocks Stora Karlsö has an extremely diverse and rich flora, and with its location at the east coast of Sweden St Karlsö has the highest number of hours with sunshine in a year for Sweden. Apart from having a ca 390 pair large lesser black-backed gull colony, there are also a number of other seabirds breeding at the island, such as Guillemots, Razorbills, Cormorants, Arctic terns etc. It also inhabits one of the largest breeding populations of barred warblers (Sylvia nisoria) in Sweden (ca 15 pairs).

You may find maps of the movements of the two lesser black-backed gulls Karla and Linnea at:
http://www.seaturtle.org/tracking/?project_id=408

Susanne