Sand knobwood Zanthoxylum leprieurii as a keystone resource for birds in Nigeria: insights from observational counts and proximate analysis

Abstract

This study investigated the importance of sand knobwood Zanthoxylum leprieurii (family Rutaceae) fruits as a food source for birds in the Tree Heritage Park, Ibadan, Nigeria. We conducted focal observations over three years (2018, 2019, and 2024) during peak fruiting periods, recording bird species foraging on fruits in the canopy and on the forest floor. A total of 4 452 birds from 30 species were observed, with the Red-eyed Dove Streptopelia semitorquata being the most frequent forager (48%). Foraging activity was higher in the morning than evening. Proximate analysis revealed that sand knobwood fruits contain 8.4% moisture, 6.7% ash, 33.5% fat, 11.2% protein, and 33.5% crude fiber, suggesting potential nutritional value for birds. These findings deepen our understanding of the intricate relationships between trees, birds, and ecosystems.