Programmable, miniature video-loggers for deployment on wild birds and other wildlife

Animal-borne miniature video cameras hold the potential to revolutionise field ornithological research, with their ability to collect detailed behavioural data from a bird's eye view, in places and contexts where conventional observation techniques would fail. Here, we describe the development of a new generation of solid-state video-loggers that are cheap, light-weight, programmable and easy to use and that overcome many problems associated with earlier transmission-based technologies. Our loggers weigh c. 12 center dot 313 center dot 6g fully packaged for deployment and record up to 94min of video footage, at 640x480 pixels and 19 center dot 7 frames per second, on a 4-GB micro-SD card. Loggers are fitted with a custom-designed, microprocessor-controlled timer that enables flexible duty-cycling, switching the unit on and off following a preprogrammed schedule. Packaged loggers contain a miniature very high frequency (VHF) radio-tag (battery life c. 59weeks) for positional tracking of the bird before, during and after scheduled video shoots, and to enable logger recovery for data download. To make our loggers suitable for deployment on wild birds, we developed novel techniques: (i) for the light-weight packaging of electronics (thin sheets produced from thermoplastic) and (ii) for the attachment of units to, and their controlled release from, subjects (UV-sensitive, rapidly degrading rubber tubing). Loggers can be manufactured at comparatively low cost (components are c. 94GBP, plus c. 145GBP for the VHF radio-tag) and are easily refurbished after recovery, making the technology suitable for large-scale deployments and projects on modest research budgets. A study in 2009/2010, with logger deployments on 19 wild New Caledonian crows Corvus moneduloides, demonstrated that our new technology is field-worthy and that it can generate rich data sets on the foraging behaviour, habitat use and social interactions of an elusive bird species. The young field of wildlife video-tracking is maturing quickly, and in only a few years, technology has advanced sufficiently to enable cost-effective, hypothesis-driven field studies of terrestrial birds, mammals and reptiles. Large-scale deployment of video-loggers can generate data sets of unprecedented information content, promising major quantitative insights in basic and applied ecology.