Seasonal covariation of feeding behaviour and weather conditions in common Shelducks ( Tadorna tadorna ) at a North African wetland

Among the North African wetlands designated under the Ramsar Convention, Chott Tinsilt was investigated due to its importance as a wintering site for large numbers of waterbirds. However, the use of this site by the Common Shelduck ( Tadorna tadorna Linnaeus, 1758) remains poorly documented, particularly regarding the influence of environmental factors on its feeding behaviour. During the wintering season ‘2015–2016’, weekly population censuses and diurnal behavioural observations were conducted. Variations in time-activity budgets were analysed using a linear mixed model (LMM) that incorporated population size and climatic variables. The results showed that feeding activity was the dominant component of diurnal behaviour, accounting for 80.3% of the time budget. This activity was significantly influenced by population size, air temperature, humidity, wind speed, and rainy days. The models also revealed significant interactions between feeding activity and climatic variables, suggesting behavioural modulation in response to environmental conditions. These findings highlight the key role of North African wetlands as daytime foraging habitats and refuges for wintering waterbirds, and emphasize the importance of their conservation for maintaining the ecological functions essential to biodiversity.