Diversity and Abundance of Insectivorous Passerines and Insect Prey in an Urban Degraded Savanna Woodland

Abstract

A good supply of insects in the diet of birds is vital for survival. Insects provide a high and easily assimilated source of protein essential to avian species life process. Both insects and birds are useful bio-indicators of the environment and therefore important systems for biodiversity conservation. This study was carried out at the Jos Wildlife
Park located within the Jos Plateau. The Park is characterized by savanna scrub, gallery forests with seasonal streams, gentle hills and rocky outcrops and some exotic plants. Insectivorous passerines were trapped using mist nets to obtain faecal droppings which were then preserved in 70% alcohol and taken to the laboratory for microscopic examination of insect fragments. Line transect was used to survey insectivorous passerines and insects in different habitat types. Insect surveys involved the use of sweep netting and pitfall trapping techniques along transects. A total of 151 bird species in 48 Families
were recorded whereas a total of 91 insect species were identified in 17 Orders and 87 Families during this study. In addition, insects collected along the transect line pointed out that the Order Hymenoptera> Diptera> Coleoptera>Orthoptera. The positive correlation between insects sampled from the faecal dropping of insectivorous passerines and those collected from the habitat types in the study area perhaps suggest that the insect diet of the insectivorous passerines is a reflection of the frequency of insect abundance and diversity in the study area. The study concludes that insectivorous passerines had a direct correlation between habitat resource availability and utilization.