Kereru in Urbanised Landscapes
Urban areas are quickly supplanting other land covers on a global scale as a direct result of a rapid human population growth and associated anthropogenic disturbances. Although the concept of a city as an ecosystem is now widely accepted, relatively little is still known about how wildlife responds to urbanised landscapes. In addition, the factors affecting habitat selection of highly mobile avian species within urbanised landscapes have seldom been quantified at multiple spatial scales. Understanding the human social aspects of urban ecology is also vital to wildlife conservation because as the majority of the world’s population continues to shift into cities, they are becoming increasingly “disconnected” from nature. However, people can contribute both directly through involvement in wildlife research, and indirectly through knowledge acquisition and environmental awareness. The kereru (New Zealand pigeon, Hemiphaga novaseelandiae) is a large, highly mobile, fruit-eating pigeon endemic to New Zealand. Although once in nationwide decline, kereru appear to have slowly increased in numbers across New Zealand, most notably in urbanised landscapes. Kereru recovery may be due to the control of mammalian predators and competitors, as well as a reflection of the kereru’s ability to adapt to and exploit novel suburban habitat. However, little is known about how kereru select amongst urbanised habitat, the impacts of injuries sustained within this habitat on post-rehabilitation success or how researchers can integrate urban residents into the conservation of kereru. This thesis aims to (1) advance current knowledge of kereru ecology within urbanised landscapes and to explore the concept of kereru as an “urban adapted” species, and (2) to examine the role of people in urban avian ecology, from the perspectives of both the researcher and the public. I applied a multi-scale approach to examine habitat selection by kereru at regional (first-order), winter range (second-order), and site (third-order) levels, using a citizen-generated dataset and by monitoring a marked and radio-tagged population in Wellington City. At the first-order of selection, citizens’ sightings of kereru revealed that birds selected areas with intermediate levels of building and road coverage when possum (Trichosurus vulpecula) control measures were undertaken. Radio-telemetry of kereru revealed that habitat selection within Wellington’s residential ecosystems occurred at the third- but not second-order of selection. Sites within winter ranges were selected based upon the presence of a native food source, conspecifics and possum control. My results suggest that possum control may be creating a buffered “safe zone” for kereru within suburban areas whereby predation risk is lowered, or more likely, competition for native food sources is reduced. While it is encouraging to see increasing numbers of kereru in urbanised areas, this environment is often the cause of injuries not normally sustained in the wildlands. I monitored kereru during the early post-release period following rehabilitation in two variably urbanised landscapes. Results of my modelling suggested that the sex of the bird, release site, severity of the injury sustained, and the time of year a bird was released were important determinants of early rehabilitation success. This thesis ends with a study that integrated local school children into my field research as part of a conservation education program. Using kereru as a focal species, I tested whether incorporating biological researchers into the classroom and hands-on experiences with radio-telemetry of wild birds in local green space increased wildlife knowledge, environmental awareness and intentions to act amongst children. No significant increases in wildlife knowledge were found in either treatment group, however those children who participated in exercises with researchers in local green space demonstrated, and retained, higher levels of nature awareness than groups who participated in the schoolyard. In summary, applying multiple methods and considering both the biological and social aspects of urban avian ecology have allowed me to gain a more holistic picture of the kereru's ability to adapt to urbanised landscapes and how people living in cities can contribute towards the conservation of kereru.