Collar? I barely know her: The utility of accelerometry in measuring personality in situ for a free-ranging wild mammal

The study of personality in animals requires methods for quantifying consistent among-individual differences in behaviour. Typically, standardized behavioural assays are used rather than in situ tools. We evaluated whether assays and accelerometry, a relatively novel method of quantifying animal behaviour in the field, yielded similar personality measurements in a wild population of North American red squirrels, Tamiasciurus hudsonicus , by comparing among-individual correlations of behaviours across these methods. Both methods described two behavioural axes, with assays capturing activity and exploration, and accelerometry capturing foraging and movement. We found higher trait repeatability ( R ) for traits measured with assays ( R adj : adults: 0.37–0.40; yearlings: 0.18–0.48) than for traits measured with accelerometry ( R adj : adults 0.11–0.19; yearlings: 0.07–0.11). Additionally, we found a significant positive among-individual correlation between the assay behavioural axis associated with exploration and the accelerometry behavioural axis associated with foraging. We also found that the repeatability of traits measured with accelerometry was related to the amount of behavioural data captured by this method. Given that accelerometry was able to quantify animal personality in situ for adults, accelerometer collars may present a possible alternative to assays for species in which assays are impractical. Our results also underscore the importance of considering the amount of behavioural data captured by different methods when assessing trait repeatability. As researchers strive to measure behavioural variation under natural conditions, sufficient behavioural sampling remains a priority. • We evaluated whether assays and accelerometry measure similar behavioural axes. • Assays captured behaviours associated with active and exploratory behaviour. • Accelerometry captured behaviours associated with foraging and movement. • We found a positive among-individual correlation between exploration and foraging. • Accelerometry presents a possible alternative to assays when assays are impractical.