Avian Encounter Rates and Interaction Network with Trees in an Urban Setting

Abstract

The interactions of birds with trees facilitate the provision of ecosystem services that are crucial for maintaining ecosystems. Knowledge of these interactions can be beneficial to conservation actions. The study assessed bird-tree interaction network and encounter rates within the Akoka campus of the University of Lagos. Focal observations of avian visits were made for 15 minutes on a total of 50 randomly selected trees spaced 200 m apart. Each selected tree was visited repeatedly from February to June 2022. A total of 14 bird species belonging to 13 families were recorded while 21 different tree species constituted the focal trees; the top three being Albizia lebbeck (n=7, 15%), Delonix regia (n=7, 15%), and Milletia thonningii (n=6, 13%). The most abundant bird species were African Thrush Turdus pelios, Common bulbul Pycnonotus barbatus, and Laughing dove Spilopelia senegalensis. Bird species encounter rates among focal trees did not significantly differ, nor did they correlate with fruiting and flowering status or diameter at breast height, but a positive correlation existed with canopy cover (p<0.05). Network analysis revealed varying bird interactions with different tree species, with some birds interacting with multiple species and others with only one. Notably, Albizia lebbeck, Delonix regia, and Milletia thonningii were highly interacted with multiple bird species. We conclude that bird conservation on the campus will benefit from the preservation of these tree species among others.