Correlates of flight response in some common birds of a rapidly expanding African city

Abstract

Human disturbance in urban landscapes is well known to influence wildlife species worldwide, but information on some animal taxa such as birds, particularly in sprawling African cities, is scarce. We investigated factors influencing alert distance (AD) and flight initiation distance (FID) for four urban bird species in the expanding Morogoro municipality in northeastern Tanzania. Data were collected along 30 transects, ten in each of urban core, peri-urban and rural zones, and analysed using mixed models. We found starting distance (the initial distance from observer to bird), species type and urbanization levels the strongest predictors of alert distance. The same factors, along with perch height, also best predicted FID. Alert distance was positively related to starting distance, and FID increased with alert distance and perching height. Little Bee-eater Merops pusillus showed the longest alert and flight distances, and House Crow Corvus splendens and Southern Cordon-bleu Uraeginthus angolensis the shortest, with Common Bulbul Pycnonotus barbatus intermediate. Encounter rates for House Crow and Southern Cordon-bleu were highest in the urban core, with Little Bee-eater and Common Bulbul preferring more peri-urban and rural settings. The overall responses are consistent with patterns reported in temperate cities, and demonstrate how African bird species variably adjust their behaviours to live in growing African cities. The results may contribute to planning strategies for continued co-existence of birds and humans in expanding urban landscapes.