This study is an avifaunistic diversity assessment was carried out in the Merine forest, Sidi Bel Abbes (Northwest Algeria). During three years (2019-2021). The major objective of our investigation is to inventory avian species and to define their phenological categories. Among the important results is a record of, 71 species of bird, belonging to 17 orders and 28 families. The Passeriformes are the most noted with 43 species, distributed across 15 families, of which the Muscicapidae is the most represented with 10 species. The phenological categories indicates that the majority of this species are resident breeders (65 %), 21% are migrant breeders and 14% are passing visitors. Depending on trophic status, 32% are polyphagous, 27% insectivorous, 17% carnivorous, 15% granivorous and 8% omnivorous. In addition, we noted that, 31 species are protected by Flat 12-235 in Algeria, with one species (Falco naumanni) protected by the Ordinance 06-05. Internationally and one species protected according of the IUCN red list (Streptopelia turtur). The Merine forest is shelter to five species endemic to North Africa: Barbary Partridge (Alectoris barbara), Levaillant's Woodpecker (Picus vaillantii), Moussier's Redstart (Phoenicurus moussieri), Tristram's Warbler (Sylvia deserticola), African Blue Tit (Cyanistes teneriffae).