Water temperature sampling by foraging Brünnich's Guillemots with bird‐borne data loggers

Abstract

We describe the features of waters where seabirds were feeding by sampling vertical water temperature profiles with data loggers mounted on five Brünnich's Guillemots in Svalbard, Norway. The guillemots foraged in a cold water (−0.5–0.5°C SST (sea surface temperature)) by making 1.8 dive bouts in short trips (32–257 min duration) as well as in moderate (0.5–2.0°C SST) and warm waters (2.5–4.0°C SST) by making 6.0 dive bouts during long trips (411–688 min duration). Judging from outbound flying time (15.7–24.4 min), time between dive bouts (23.9–43.3 min) and water types, the birds probably fed in fjord or coastal waters during short trips and in both coastal and offshore waters during long trips. Water temperature and diving behaviour can be simultaneously recorded by small data loggers, which therefore will provide useful information on marine features and foraging activity of top predators.