Observational studies
To assess learning from an observational perspective, we must analyze how an animal behaves at a given time based on local conditions and past experiences. In practice observational studies typically record the location of animals and thus their experiences over relatively long time-frames (e.g., multiple years, or entire lifetime). Remotely sensed geographic and climatological data then provide the local conditions the animal is experiencing during movement. Additional information on the behavioral and physiological states of the animal may also be relevant. Fortunately, the ongoing evolution in remote animal tracking and sensing technology means that we are increasingly able to measure physiological and behavioural states over long periods of time (Kays et al . 2015).
Data on repeated movement patterns can help us differentiate between hypotheses about learning. For example, data on repeated migration routes has been used to determine whether animals follow resource gradients, rely on memory to navigate, or learn from experience to shape their movement decisions (Mueller et al . 2013, Merkle et a l. 2019). However, long-term tracking data may also be sufficient for analysis. For example, long-term data tracking the movement of wolves has been use to determine whether animals only follow resource levels, or also rely on the memory of time since last visit to a location (Schlägel et al. 2017). Augmenting tracking data with direct data on the information that the animals might gather, for example the location of kill sites (Gurarie et al . 2011) or profitable forage patches (Merkle et al . 2014), can further enhance our understanding of how animals monitor their environment through time (Gurarieet al. 2011).
Comparative studies can be useful for identifying instances of learning. For example, comparing the movement efficiency of juveniles and adults shows that seabirds start by exploring their landscape and then learn to identify the good foraging areas and cues as adults (de Grissac et al. 2017; Votier et al. 2017; Grecian et al. 2018; Wakefield et al. 2019). Effects of early-life experience can also be identified by analyzing the site fidelity of animals to their breeding ground (Weinrich 1998) and by comparing the migration patterns of offspring to those of their mother’s (Colbecket al. 2013). Finally, comparing the movement of cultural groups, especially if sympatric, can help to assess the effect of culturally transmitted information on animals’ use of space (Kendalet al. 2018; Owen et al. 2019).