Seasonal and Environmental Drivers of Bird Community Composition in a Tropical Savannah Landscape

ABSTRACT

Understanding how environmental and structural factors shape bird communities is critical for biodiversity conservation in tropical savannah ecosystems. In this study, we examined the effects of seasonal variation and fine‐scale vegetation structure on bird community composition within a protected savannah woodland at the Federal University Lokoja Zoo and Conservatory, north‐central Nigeria. Bird surveys were conducted using line transects between February and May 2025, spanning the dry and early wet seasons. In total, we recorded 562 individuals representing 66 species across 37 families. Vegetation structure and environmental variables were measured at the transect level, and community patterns were analysed using multivariate and regression‐based approaches. Bird community composition differed significantly between seasons, reflecting both shifts in species composition and variation within seasons. Species richness and Shannon diversity were higher during the wet season, whereas total abundance did not vary significantly. Ordination analysis indicated that vegetation structure was the primary driver of community organization, with grass height, shrub density and tree cover showing the strongest relationships with species composition. Generalized linear models further identified shrub density as the most consistent predictor, positively influencing species richness, abundance and diversity, while canopy cover showed negative associations with abundance and diversity. Indicator species analysis revealed clear seasonal patterns, with nectar‐feeding sunbirds associated with the dry season and insectivorous and omnivorous species more common in the wet season. Overall, our findings emphasize the role of fine‐scale habitat heterogeneity in shaping bird communities within small savannah fragments and provide valuable baseline data for biodiversity monitoring in understudied West African ecosystems.