Tracking reveals skua 'meeting points' in open ocean


A recent study by the British Trust for Ornithology (BTO), in collaboration with other research organisations, investigated Arctic Skua migration, revealing the species' use of predetermined mid-ocean 'meeting points' during their long journeys.

Arctic Skua, which is well known for its parasitic feeding behaviour, is in sharp decline and therefore much-studied in an effort to understand the threats it faces. The BTO study sought to build knowledge of the skua's migration routes and behaviour, to better understand the threats it may face while travelling between the breeding grounds and wintering areas.

Arctic Skuas bound for different wintering areas converge in key areas of the open ocean during migration (Ian Dickey).

The BTO fitted tracking devices on nesting Arctic Skuas across northern Scotland, Norway, the Faroes and Svalbard. The tracks gathered revealed the individual skuas' routes during spring and autumn migration. Despite nesting in widely scattered locations, many skuas converged at specific mid-ocean sites to rest and feed while on their way between breeding sites and wintering areas.

These remote ocean areas serve as key stopovers for various seabirds and other marine wildlife. After converging at these Atlantic hot-spots, tracking revealed that the skuas disperse in different directions, meaning these critical areas serve birds that both breed and winter in a range of different locations, and that they need protection.

Nina O'Hanlon, Senior Research Ecologist at the BTO, said: "By identifying the various routes and stopping off points these wide-ranging seabirds use we can start to identify threats they may encounter along the way and further safeguard these areas.

"By revealing how extensively skuas mix during migration we can also now better understand how their experiences during this period can impact the fate of multiple breeding populations."



O' Hanlon, N K, van Bemmelen, R S A, et al. 2024. Atlantic populations of a declining oceanic seabird have complex migrations and weak migratory connectivity to staging areas. Mar Ecol Prog Ser 730:113-129. DOI: https://doi.org/10.3354/meps14533