Population dynamics and wintering behavior of the black–headed gull Chroicocephalus ridibundus at El Mellah lagoon (Northeastern Algeria)

Abstract The population dynamics and behavior of the black-headed gull of an Algerian coastal wetland, El Mellah lagoon (Lake Mellah), were studied during three consecutive wintering seasons (2018–2021). Maximum numbers of the species were counted in December and January depending on the year. A peak of 536 individuals was recorded in the first half of December 2018, another of 538 individuals in the second half of December 2019, and a final peak of 636 birds in the first half of January 2021. Diurnal activity patterns showed that feeding was the primary behavior, with a mean of 24% for the three seasons. It was followed by sleeping (21%), swimming (19%), preening (18%), and flight (17%). Black-headed gulls appeared to be more active in the morning than at other times of the day. This study attempts to provide recent and unpublished data on the wintering and behavior of the black-headed gull, which remains poorly documented in North Africa and particularly in Algeria, and highlights the patterns of wetland use by these species, which could help to evaluate the importance of certain areas and develop management plans specific to coastal habitats and their avifaunal diversity.