Trends in at-sea tracking statistics of the Little Penguin from 2005 to 2012

Much of what we see penguins doing on land, including their breeding success, relates to their fishing success at sea. Environmental conditions can affect where prey species are located, which in turn affects the distance... [ view full abstract ]

Much of what we see penguins doing on land, including their breeding success, relates to their fishing success at sea. Environmental conditions can affect where prey species are located, which in turn affects the distance penguins may have to travel to find food. Current knowledge of the foraging ecology of the Little Penguins at Cullen Cove on Phillip Island shows that they routinely forage to the south and south-west of the island. Individual trips extend 25 to 30 km from the colony during guard phase, when birds alternate between feeding and guarding young chicks. The distance travelled increases as chicks grow and the breeding season progresses into post-guard, when both parents go to sea each day. Using satellite tracking, we investigated 246 foraging tracks of adult Little Penguins during the guard and post-guard phase of breeding for seven years. Bayesian statistics, in particular Markov chain Monte Carlo methods, were used to model the trends in the trip statistics for the time series and investigate the differences between the two phases of tracking. The maximum distance from the colony and the trip duration varied over the time period, with greater values between 2008 and 2010. The 2008 breeding season was also a time of low fledging success for little penguins on Phillip Island, further supporting the link between foraging success and breeding success. Environmental variables were used to investigate their influence on the maximum distance and duration of the Little Penguins’ foraging trips. Also, the effect of trip statistics on breeding success was examined. Such relationships between foraging ecology, breeding statistics and environmental variables improve our understanding of how Little Penguins will respond in the future to environmental variations such as climate change.