Owls as Pest Control Study

  • Introduction

    The overall aim of the project is to investigate the effectiveness of using owls in urban areas as a form of bio-control against rodents.

    Rodent control is considered essential to maintaining healthy human-built environments, and yet the methods used by both individuals and pest control contractors can cause further biological degradation by introducing toxins into the food chain that ultimately exacerbate the problem, by removing key natural predators such as owls. Reduced use of poisons could lead to a healthier population of urban owls, which would in turn act as a brake on rodent numbers.

  • Researcher: Robyn Angela Lowe

  • Background

  • Modern human lifestyles (especially our habits of eating in the street and discarding food waste haphazardly) have created ideal opportunities for commensal species – i.e., where one species benefits, and one is unaffected – of which rats are probably the most notorious example.

    Rats and other rodents maybe successful on their own terms, but they are regarded as problem animals and heavily (although often futilely) persecuted in urban areas. Rodent control measures tend to address the symptoms (infestations) rather than the underlying causes.

    The use of poisons to kill rodents is regarded as more effective than traps. However, it can lead to the accumulation of fatal poisons in the bodies of predators and scavengers that feed on rodents. This factor aside, Johannesburg is in many ways ideal owl habitat. There are many places to nest and roost (large numbers of trees, and owl boxes put up by some residents) and a ready food supply. It is the food supply, however, that is the issue.

  • Objectives

    To gather data on owl box distribution and colonisation across Johannesburg to understand the current status of the city’s urban owl population, and to raise community awareness of the potential of owls as a means of bio-control against rodents.

    To investigate the effectiveness of the Spotted Eagle Owl (Bubo africanus) and the Barn Owl (Tyto alba) as a form of rodent bio-control in Johannesburg by collecting data from occupied owl boxes.

  • Methodology

    • Data collection from people who have installed owl boxes on their properties, looking especially at the presence of owl pellets as proof of owl box occupation.
    • Semi-structured interviews used to analyse cultural mind-sets and beliefs that people have towards owls in urban areas as a way of assessing their openness to bio-control by owls rather than the use of poisons.