Hierarchical regression models to explain murmuration size (number of birds) and murmuration duration (minutes) based on either temperature and predator presence or temperature and predator activity (perching silent, perching calling, flying, interacting with flock).

In all cases, three models were created: (1) Minimum Adequate Model (MAM)–the most parsimonious model (i.e. the model that had fewest predictors whilst still attaining ΔAIC < 2); (2) Optimal—the model that best balanced the number of variables and explanatory power (i.e. ΔAIC = 0); and (3) Maximum—the model that increased adjusted R2 to the maximum possible within the ΔAIC < 2 limit. See methods for more details.