Inexpressible Island, Victoria Land, Antarctica, to monitor1622 Polar Biology (2019) 42:1621–16241 3the breeding status of Adélie Penguins, of which there were approximately 24,450 breeding pairs in 2012 at this site (Lyver etal. 2014). We visited the penguin colony three times during incubation (4, 6, and 7 Dec), four times during chick guarding (12, 13, and 14 Dec and 2 Jan), two times during crèche (7–10 and 28–29 Jan) and once during the late molting and migration period (11 Feb). During each visit, 4–5 researchers performed field observations near the penguin colonies and checked for the presence of pin-nipeds near the sea shore. Weddell seals were continuously recorded resting on the sea ice near the penguin colony, and a leopard seal was occasionally observed.On 28 January 2018, two Weddell seals were frequently found near the sea shore. No hunting behaviors were observed, but the seals appeared to be searching this area. On 11 February 2018, we investigated the diving behavior of fledgling Adélie Penguins. Juvenile penguins were in the