Parentheses indicate that the number may not be accurate because of premature interruption of the record due to tag failure or death of the animal. These numbers were excluded from the calculations of the summary statistics presented at the bottom of the table.

The departure mass is given as the last recorded mass, typically measured 4.2±3.3 days (mean ± s.d.) prior to the last sighting of the individual at the Isthmus study colony. The departure mass on the actual day of departure was estimated by extrapolation from the last recorded mass at a mean individual daily mass loss rate (the difference between weaning mass and last recorded mass divided by the number of days between them). Since the difference between the last recorded and estimated mass was typically very small (1.8±0.4 kg, or 1.97±0.3%), we have consistently used the last recorded mass. ^bThe record duration is the last day after departure at which data were received from a tag, while the trip duration is the number of days between departure and the first sighting of a seal back at Macquarie Island. ^cThe first and last days for which a positive change in drift rate was observed are presented as day after departure(`First' and `Last'), while `Max' represents the day after departure at which the maximum positive change was observed. ^dThe number of days between the first and last days for which a positive change in drift rate was observed. ^eThe total number of days for which a negative (−)and positive (+) change in drift rate was observed.