Morus bassanus

The gannet is an emblematic bird of the North Atlantic. The only French colony in the Sept-Iles Archipelago is Europe’s most southerly colony, home to around 20,000 pairs. Most gannets migrate to southern Europe and West Africa in winter, but some northern individuals winter along the French coast. They fish by making spectacular dives at nearly 190 km/h.

Gannets have been studied in France for many years, but very few data are available on the distribution of juveniles and adults at sea at the end of their breeding cycle. Hard hit by the outbreak of highly pathogenic avian influenza in 2022, the colony lost almost 45% of its workforce. Boobies are also threatened by the increasing scarcity of fish, for which they compete with humans. They are also potentially vulnerable to collisions with offshore wind turbines, as they regularly fly at altitudes of over 20m, looking downwards.

Almost every year since 2005, a CEFE scientific team led by researcher David Grémillet, a partner in the Migratlane program, has visited Rouzic Island in the Sept-îles archipelago national nature reserve to study gannets. Many adults have already been fitted with GPS tags during their nesting period, enabling us to acquire a wealth of knowledge about this species.

In 2023 and 2024, late-breeding adults and fledglings will be captured on their nests and fitted with GPS for the Migratlane program. Data is lacking for this period of their cycle.

The crazies are equipped with OT9 GPS beacons that record geographic position, altitude, tri-axial acceleration and temperature. These 9g beacons transmit data regularly via the 3G system. To limit the impact of the beacon during the birds’ rapid and repeated dives, the beacons are very small in relation to the size of the boobies, and attached to the bird’s rectrices (tail feathers) with special tape. Beacons fall off after a few weeks due to tape wear or feather moulting.

    ^{Migratory in France}

  ^{Breeder in France}

   ^{Wintering in France}