Energetic consequences of prey type in little penguins (Eudyptula minor)

Investigation of foraging decisions can help understand how animals efficiently gather and exploit food. Prey chase and handling times are important aspects of foraging efficiency, influencing the net energy gain derived from a prey item. However, these metrics are often overlooked in studies of foraging behaviour due to the difficulty in observing them. The present study used animal-borne cameras to investigate the type, duration and energetic consequences of predator-prey interactions in little penguins (Eudyptula minor) (n = 32) from two colonies in Bass Strait, south-eastern Australia. A total of seven main prey items were observed and consumed by little penguins. Penguins were observed to consume prey types and use strategies that have not been previously documented. These included consumption of bellowsfish (Macroramphosus scolopax) and other fish species captured sheltering around jellyfish or extracted dead from the tentacles. Chase and handling time varied with prey type and lasted approximately 2 s for most prey. Profitability varied among prey types, with a greater amount of low profitable prey being consumed, suggesting a trade-off between minimizing energetic costs, and increasing capture rates. These results highlight the use of animal-borne video data loggers to further understand the foraging adaptations of important predators in the marine environment.

Automated summary

Investigating foraging decisions helps understand how animals efficiently obtain and use food. This study used animal-borne cameras to examine predator-prey interactions in little penguins, discovering previously undocumented prey consumption and strategies. The study found that chase and handling times varied with prey type and that penguins consumed less profitable prey, suggesting a trade-off between minimizing energetic costs and increasing capture rates. These results demonstrate the importance of animal-borne video data loggers in studying foraging adaptations of marine predators.