**5. Conclusion**

The results show that *V. tortilis*-dominated habitat has greater species richness, abundance, and diversity compared with *Commiphora*-dominated vegetation or *V. robusta* suggesting that the species of the tree itself, was an important factor determining the distribution of birds. Grasslands in the western and northern part of the Serengeti National Park accommodated a higher abundance of birds due to treefeeding birds moving into grasslands to exploit the available resources. This pattern of birds nesting and roosting in *Vachellia*-dominated vegetation and moving into grassland to feed was not observed in the grassland and *V. seyal*-dominated vegetation. In addition, *V. seyal*-dominated vegetation provided different food resources from those

of *V. drepanolobium*-dominated vegetation so it was the difference in tree species that explained the differences in the abundance of birds. This study found that bird diversity did not decrease linearly with grass height, it reached a peak at intermediate grass heights. In the western and northern parts of the park, bird diversity increased as grass height became shorter due to fire and grazing by ungulates.
