High definition video loggers provide new insights into behaviour, physiology, and the oceanic habitat of marine top predators

Camera loggers are increasingly used to examine behavioural aspects of free-ranging animals. However, often video loggers are deployed with a focus on specific behavioural traits for which it suffices to use cameras that are small but often have a limited field of view, poor light performance and video quality. Yet the rapid developments in consumer electronics provide new devices with much improved visual data which allows a wider scope for studies employing this novel methodology. We developed a camera logger that records full HD video through a wide-angle lens, providing high resolution footage with a greater field of view than other camera loggers. Main goal was the analysis of foraging behaviour of a marine top-predator, the Yellow-eyed penguin in New Zealand, with regards habitat characteristics. Yet, visual data recorded proved to contain much broader information than anticipated. Frame-by-frame analysis allowed accurate timing of prey pursuits and time spent over certain seafloor types. Similarly, it was possible to time breathing intervals between dives and quantify exhalation events during prey events, a previously undescribed behaviour. Using screen overlays we analysed flipper angles and beat frequencies throughout the various phases of a dive. The recorded video footage showed that prey species were associated with certain seafloor types, revealed different predator evasion strategies by benthic fishes, and highlighted varying energetic consequences for penguins pursuing certain types of prey. Flipper movements analysis confirmed decreasing effort during descent phases as the bird gained depth, and that ascent was principally passive. Breathing episodes between dives were short (<1 s) while the majority of the time was devoted to subsurface scanning with a submerged head. Video data recorded on free-ranging animals not only provides a wealth of information recorded from a single deployment but also necessitates new approaches with regards to analysis of visual data. In this paper, we demonstrate the diversity of information that can be gleaned from video logger data, provide various analysis approaches to visual data and highlight the importance of video quality and field of view significantly increase quality of the resulting data.