Rainy season dietary ecology of avian species in semi-refuge habitats in Kano, Nigeria

Abstract

Birds are important natural field components, and critical to most ecosystems by supporting seeds dispersal, plant pollination and pest control amongst other functions. Data on avian diversity and feeding behavior could be used to enhance habitats and help initiate conservation strategies. Thus, to characterize the diet of local avian fauna, we selected four semi-refuge sites around Kano metropolis, where we established 22 line transects, each 900m long, spaced 150m apart. During May to October, 2017 each site was visited once a month, adding up to 132 transect-visits. Daily surveillance starts between the local hours of 6:30am to 10:30am. We also transect-surveyed tree vegetation for evaluation of the avian habitats. We recorded a total of 22 bird species belonging to 15 families, with ploceidae as the dominant, and the Laughing dove, Streptopelia senegalensis (Family: Columbidae), being the most dominant species. Over 40% of the bird species fed on insects, other arthropods and earthworms; followed in proportion by seed eaters; while only 3.7% were nectar feeders. Goodness of fit test on observed versus expected dietary item frequencies was significant (Chi-Sq=31.49; P=0.000), indicating field cafeteria habits were not random, but selective or, probably even evolutionary. The manner of food search varied amongst the species, with the Yellow-billed oxpecker, Buphagus africanus and Cattle egret, Egretta alba, expending the most continuous foraging time of 30 to 60 minutes. However, some species, e.g., Senegal coucal, Centropus senegalensis, mainly adopted the pick-and-move strategy. The Shanon- Wiener indices of diversity, H, by site, for birds was fair to moderate (1.24 to 2.53) and paralleled those for the trees. In the light of dearth of avian ecological data from the Kano region, we invite motivated ornithologists, bird enthusiasts and public agencies for research into avian movement patterns, and conservation measures that, we believe, must include habitat protection.