Birds are the most known animals however; the majority of avian species have been threatened as a result of habitat modifications. The aim of this study was to investigate diversity, relative abundance and habitat association of bird species in Mertule -Mariam Town. The study was conducted from November to July 2023 covering both the dry and the wet seasons. Based on heterogeneity, the study area was stratified into three habitat types; namely human settlement, monastery, and tannery area. Belt transect and line transect methods were used to collect data. The belt transect were used in monastery while the line transect in both human settlement and tannery area. Shannon-Weiner diversity index, Evenness Index , Species richness and Sorensons ՛ s similarity index were used for data analysis. The habitat association of birds was analyzed by using chi-square test and one way ANOVA was conducted to check the significance difference as bird abundance in the three habitats. A total of 46 bird species belonging to 10 orders and 29 families were identified with 33 and 36 species during the dry and wet seasons, respectively. Among them 23 species were recorded during the dry and the wet seasons. Ten and thirteen species of birds were observed exclusively during both dry and wet seasons, respectively. Order Passeriformes had the highest number of families 69 % (n=20) and the other nine orders had the lowest number of family 31.1 % (n=1). Four species White-collared Pigeon (Columba albitorque), Thick-billed Raven (Corvus crassirostris), White-winged Cliff chat (Monticola semirufus), and Wattled Ibis (Bostrychia carunculata) are endemic to both Ethiopia and Eritrea recorded in the study area. The highest number of avian diversity index (H՛ ) was recorded in the human settlement area (H՛ =2.54) and the lowest was in the tannery area (H՛ =1.83). The highest evenness index was recorded in the Monastery (E=0.856) and the lowest was in the tannery area (E=0.761). More species similarity was observed between the human settlement and the tannery area (SI=0.605) during the wet season and the lowest was between the Monastery and the tannery area (SI=0.36) during the dry season. Relative abundance of different avian species showed significant difference (P<0.05) among the three habitat types. Test of association between season and habitat type as a function of bird abundance showed that there was no significant association between season and bird abundance in different habitat types P>0.05). Further ecological study, awareness creation about the important of birds to the local community, and conservation measures need to be taken.