Exploring new depths: king penguins break dive records during the austral winter

The king penguin is one of the champion avian divers, surpassed only by its larger relative, the emperor penguin. The foraging ecology of king penguins is typically studied during the austral summer, when foraging trips are relatively short (weeks). Consequently, little is known about the autumn-winter period, when birds undertake long foraging trips (months) and the descent of their preferred prey to greater depth might challenge their dive capacity. Investigating the dive behaviour of seven king penguins from the Crozet Islands during autumn-winter, we found that birds conducted deeper and longer dives during this period. Most birds exceeded the previous depth and duration records but the deepest (424.5 m) and longest (10 min) dives were conducted by the same individual. These dives are the deepest and longest yet reported for king penguins and illustrate their ability to respond to seasonal changes by enhancing their dive capacity, likely through gradual acclimatization.