Respectful gannets do not overstep their boundaries

Gannets will respect a rival colonies’ fishing grounds despite showing no displays of territorial behaviour, scientists have found.

Researchers from the Universities of Leeds and of Exeter showed that these gannets will purposefully avoid the fishing grounds of neighbouring colonies while they hunt.

“The reason is to do with how they compete for food resources at sea,” says Dr Keith Hamer, co-lead author of the research and reader in animal ecology in the University of Leeds ’faculty of biological sciences.

Gannets are Europe’s largest seabird, with a wingspan of around 2m, and nest on steep cliffs and rocky islands in colonies.

Gannets rely on birds like puffins and guillemots, and dolphins or predatory whales to drive fish up to the surface, says Dr Hamer. Gannets need to find these “feeding associations” without competing gannet colonies.

Gannets need to learn where the good places to feed are, Dr Hamer continues. If all a gannet ever encounters at these feeding grounds are other gannets looking pleased with themselves, they learn where the good spots are.

If you look at ants, for instance, they will defend territories very aggressively to the point the territories end up touching but not overlapping, says Dr Hamer. Gannets need not defend aggressively, but still end up with the same clearly defined boundaries. They don’t need to exhibit aggressive behaviour to keep others out of their territories.

These findings open new doors to understanding other species’ behaviours.

There is no reason to believe these behaviours are unique to gannets, says Dr Hamer.

The research will be published in Science later today.