Cover Picture and Issue Information

This month’s cover image looks into the eye of a Verreaux’s eagle ( Aquila verreauxii ). This species is found in mountainous regions of sub‐Saharan Africa, where cliffs provide suitable nesting habitat. The eagle pictured here is equipped with a tracking device from the University of Amsterdam Bird Tracking System ( www.UvA‐BiTS.nl ). In South Africa concerns over the impacts of land use change and the development of wind farms have led to the implementation of tracking studies to better understand movement patterns of this majestic bird. Such studies have provided a wealth of high‐resolution data and opportunities to explore sophisticated statistical methods for analysis of animal behaviour. Leos‐Barajas et al. use accelerometer data from aerial (Verreaux’s eagle) and marine (blacktip reef shark) systems to demonstrate the use of hidden Markov models (HMMs) in providing quantitative measures of behaviour. HMMs are well suited to analysing animal accelerometer data because they account for serial autocorrelation in data and importantly they allow for inferences to be made about relative activity and behaviour when animals cannot be directly observed. In addition, HMMs provide data‐driven estimates of the underlying distributions of the acceleration metrics, and the probability of switching between states, possibly as a function of covariates. The framework provided in the author’s paper “Analysis of animal accelerometer data using hidden Markov models” can be applied to a wide range of activity data, thereby providing exciting opportunities for understanding drivers of individual animal behaviour. Photo credit: © Andrew Jenkins