Behavioural responses to air temperature change in helmeted guineafowl <i>Numida meleagris</i>

Deciphering the behavioural responses of helmeted guineafowl Numida meleagris (Linnaeus, 1758) to temperature variation is key to understanding its eco-ethology and implementing sound management strategies. Here, we tested the ‘warmer together’ hypothesis, which states that thermoregulatory cost reduction (i.e. body heat conservation) is achieved by individuals grouping in winter. Time-scan sampling data were extracted from a live-stream webcam in Madikwe Game Reserve (South Africa) from September 2020 to August 2021, recording thermoregulatory postures, group size and social distance. We also characterised guineafowl behaviour and habitat use along with environmental variables to further investigate the leading hypothesis. We found that thermoregulatory postures are mainly used to maintain homeostasis since no relationship emerged between variation in group size and air temperature. Moreover, roosting occurred with birds clumped in family units and no physical contact. Our data suggest that body heat loss due to low winter temperatures might spur guineafowl to forage on dry vegetable matter to maintain homeostasis. In addition, drinking frequency and air temperature were strongly related, with their relationship being negative in presence of high windspeed. Based on these findings, we reject the ‘warmer together’ hypothesis in favour of food finding and vigilance as drivers of grouping behaviour in the helmeted guineafowl. We also suggest that habitat heterogeneity is crucial for guineafowls’ daily budget activities, and that, therefore, managing food availability and vegetation cover might be more important than water resources to secure population viability and sustainable hunting of this valuable game species