Methodology:

Temperature-Depth recorder (TDR) devices were fitted to 51 Adelie penguins on Signy Island over three seasons between December and February, 2011 to 2019. Breeding penguins were caught during incubation, brood and creche periods and fitted with TDR loggers (Lotek LAT 1810 or CEFAS G5s) using Tesa tape and a two-part quick-setting glue. Handling time did not exceed 10 minutes for deployment and 5 minutes for retrieval. Loggers were always less than 1 percent of the bird's body mass.

Devices were retrieved on average after 4.7 days. Data includes temperature, pressure and a timestamp.

The number of tags with data per year are as follows:

2011-2012: 12

2013-2014: 23

2015-2016: 11

Data collection:

Lotek LAT 1810 (6 g in air, 38 x 11 mm)

CEFAS G5s (either 2.7 g in air, 31 x 8 mm; or 6.5 g in air, 35 x 12 mm)

Data quality:

Files were consolidated to include only the timestamp, pressure in dBars, and temperature in degrees Celsius. When known, the temperature was recorded as internal, external or both. If not known, the temperature is recorded as 'Temperature'. Internal temperature relates to the sensor inside of the instrument, whereas the external temperature means the sensor was on the outside of the instrument.

Where the sex of the bird was not known, 'U' was used in the metadata file.