Little penguins stalk their prey in groups, but when it comes to catching and killing them, it’s every bird for themselves, new Deakin University research shows.
The new study from Deakin’s Centre for Integrative Ecology, within the School of Life and Environmental Sciences, is the next stage of research that last year found little penguins worked deliberately together to hunt their food.
The latest chapter investigated why they formed groups when foraging and if it gave them greater chance of capturing their prey.
Deakin researcher Grace Sutton, who completed the project as part of her honours, said this was not the case, finding little penguins were no more successful in catching prey in groups than on their own.
During the study, the same 21 little penguins (Eudyptula minor) studied in last year’s research were fitted with miniature video cameras and GPS tracking devices at London Bridge in south-west Victoria’s Port Campbell National Park, so researchers could monitor their breeding and foraging patterns.
Ms Sutton said she was surprised by the findings.
“What we did find was that when hunting in groups little penguins appeared to have more chance of finding their prey than when on their own,” Ms Sutton said.
“But finding prey is only half the challenge. The penguins had no more chance of capturing and then eating a meal when they were in groups.”
The research supervisor, Associate Professor John Arnould, said another interesting finding from the research was that little penguins were more likely to forage in groups when hunting prey that were also schooling in groups than when their catch were on their own, regardless of prey type.
“We also found success was greater when individuals hunted schooling rather than solitary prey,” Associate Professor Arnould said.
“Further to this, little penguins are susceptible to falling victim to higher order predators due to their size, so we think that foraging in groups may be a strategy to ward off attacks.”
“The moral to our research is that group hunting is a great strategy to avoid being hunted themselves, and to detecting the whereabouts of their own prey, but when it comes to catching fish, it’s every penguin for themselves.”
“This is a great step forward in our research in terms of understanding the foraging strategies of our little penguins.”
The study, Benefits of group foraging depend on prey type in a small marine predator, the little penguin, is published in today’s edition of Plos One.