Table 2 Static and dynamic environmental predictors used to examine Adélie penguin movement-environment relationships

Static variables

Bathymetry (BATH)

Estimated sea floor depth (m) at a 0.02° × 0.02° spatial resolution [66]. Influences the horizontal and vertical circulation of water masses, upwelling nutrients and enhancing productivity [67]

Bathymetry slope (BS)

Gradient (°) of the sea floor calculated from BATH data at a 0.02° × 0.02° spatial resolution [66]. Ecological importance analogous to BATH [67]

Dynamic variables

Sea-ice concentration (SIC)

Passive microwave estimates of daily sea ice cover (%) extracted at a 25 km x 25 km spatial resolution (the finest resolution available over the whole study period) [68]. Provides insight into open water accessibility or as a resting platform [69]

Sea surface temperature (SST)

Measured daily in °C at a 0.25° × 0.25° spatial resolution [70]. Reflects the temperature of water masses and fronts, which can influence biological productivity [71]

Sea surface height (SSH)

Variability of the daily sea surface height (m) at a 0.25° × 0.25° spatial resolution, obtained using E.U, Copernicus Marine Service Information (http://marine.copernicus.eu). Indication of water masses and fronts. Ecological importance analogous to SSH [71]