Methodology:

Argos Platform Terminal Transmitters (PTT) devices were fitted to 63 chinstrap penguins between December and February 2000-2016. Each PTT was fitted to the lower medial portion of the back of each penguin, using Tesa tape and a two-part epoxy resin to secure the device to their feathers, ensuring the position of the device did not hinder the bird's movement, or access to their preen gland. Handling did not exceed 10min. Each bird was restrained using a net or noose pole, according to existing BAS procedure.

Device specifications for each deployment year are specified below. Additional information where known is also provided.

2000-2003:

Deployment: 42 birds fitted with devices between January and February.

Device: SirTrack ST-10 (115x44x15 mm, 94g) or SirTrack ST-18 (115x44x15 mm, 97g). PTT tags had a minimum transmission interval of 45s seconds.

2014-2016:

Deployment: 21 birds fitted with devices between December and February.

Device: KiwiSat 101 transmitters (125x43x20 mm,107 g) or KiwiSat ST-10 transmitters (135x32x18 mm, 107g). Some devices were fitted with a saltwater switch that reduced the transmission rate when they were out of the water, either on land or on ice. The reduced transmission rate was intended to conserve battery power.

Data quality:

Satellite uplinks are given error values as the loc_class and loc_ind, which have an associated readme file further describing their values. The loc_class field indicates an error value for the location which is determined by the number of satellites the tag connected to. The loc_ind field indicates the IQ (quality indicator), which gives information on the transmitter in terms of X and Y.

PTT location data were obtained from the ARGOS system (www.argossystem.org).

Deployment data is filtered to include uplinks within trip duration provided in the metadata. When trip start and end timestamps were not provided, the first and last uplink for that deployment were used.