We tracked 94 common and 50 Brunnich''s guillemots from five colonies around Iceland (Latrabjarg, Grimsey, Langanes, Skrudur and Papey) during late incubation and chick rearing from June to July 2019. We also tracked 5 common and 3 Brunnich''s guillemots from Langanes during chick-rearing in July 2020 (GPS only). Finally, we tracked 4 common and 4 Brunnich''s guillemots from Langanes during late incubation and chick rearing in June 2021. We used Pathtrack nanoFix GPS loggers to record locations every 3min and Cefas G5 TDR loggers to record depth every second. The tags recorded the birds'' behaviour for a few days (typically 2 to 3). The aim was to investigate the foraging behaviour of the two species and the potential competition between them. Funding was provided by NERC grant NE/R012660/1 (part of the NERC Changing Arctic Ocean programme).

This dataset comprises Argos PTT data for Adelie penguins, Pygoscelid adeliae, at Signy, Powell and Laurie Islands, part of the South Orkney Islands, between December and January 1999-2014. Tags were deployed across the South Orkney Islands (Signy Island, Powell Island and Laurie Island) between December and January (austral summer). The tracking data encompasses the breeding and post-breeding migratory dispersal of chinstrap penguins. The data includes coordinates for satellite uplinks for each tag and respective trip, along with error values for each satellite uplink. Metadata includes additional information about nesting and morphology, when available. PTT tags were deployed by British Antarctic Survey (BAS) personnel and supported by Natural Environment Research Council (UK) core funding and WWF grant GB095701

This dataset comprises Platform Terminal Transmitter (PTT) data for chinstrap penguins at Signy, Laurie and Monroe Islands, part of the South Orkney Islands, between December and February 2000-2016 (austral summer). The tracking data encompasses the breeding and post-breeding migratory dispersal of chinstrap penguins. The data includes coordinates for satellite uplinks for each tag and respective trip, along with error values for each satellite uplink. Metadata includes additional information about nesting and morphology, when available. PTT tags were deployed by British Antarctic Survey (BAS) personnel supported by Natural Environment Research Council (UK) core funding, WWF Grant (GB095701), Darwin Plus grant DPLUS054 and CCAMLR special fund.