In this study, we surveyed and documented diversity and nesting of avian species and their foraging and breeding resources along the Oued Bouhellou watershed (North-Eastern Morocco). 

A total of 120 field visits were conducted between 2018 and 2022. We recorded 85 avian species of migrants and residents, belonging to 25 families and 8 orders. The families of Accipitridae (12 species) and Muscicapidae (10 species) were the most abundant, while the observed families of Corvidae, Sturnidae, Prunellidae, Caprimulgidae, and Ciconiidae were represented less abundantly, i.e., by one species each. Equally, nests of 17 breeding species were recorded and mapped along the watershed, breeding counts of the globally endangered Egyptian vulture and the globally vulnerable Turtle Dove pairs were done, and the first breeding cases of the Western Bonelli’s Warbler, Woodchat Shrike, Great Grey Shrike, Common Nightingale, Black Kite, and the North African Long-legged Buzzard were confirmed. The nesting sites were distributed along the watershed depending on specific requirements of each species, with nesting sites of passerines separated from those of raptors. The species richness of birds is supported by the availability of both foraging and breeding resources. In summary, in this study, we recorded the avian diversity, mapped the nesting sites of the breeding bird species, and confirmed the first breeding cases for five species, thus significantly contributing to the ornithology of Morocco and the Southern slope of the Mediterranean basin.