Ecological inference using data from accelerometers needs careful protocols

1. Accelerometers in animal-attached tags have proven to be powerful tools in behavioural ecology, being used to determine behaviour and provide proxies for movement-based energy expenditure. Researchers are collecting and archiving data across systems, seasons and device types. However, in order to use data repositories to draw ecological inference, we need to establish the error introduced according to sensor type and position on the study animal and establish protocols for error assessment and minimization. 2. Using laboratory trials, we examine the absolute accuracy of tri-axial accelerometers and determine how inaccuracies impact measurements of dynamic body acceleration (DBA) in human participants, with DBA as the main acceleration-based proxy for energy expenditure. We then examine how tag type and placement affect the acceleration signal in birds, using (i) pigeons Columba livia flying in a wind tunnel, with tags mounted simultaneously in two positions, and (ii) back- and tai...