Breeding performance of an apex predator, the peregrine falcon, across urban and rural landscapes

Abstract

Urban environments present wildlife with major challenges and yet surprising numbers of species have colonised towns and cities globally. Despite the growing realisation that urban centres can be important habitats for wildlife, why some species do better than others in urban environments remains poorly understood. Here, we compare the breeding performance of an apex predator, the peregrine falcon (Falco peregrinus), in urban and rural environments, and test whether variation in reproductive success between and within environments is driven by prey. Historical breeding data were collected from raptor study groups across Great Britain between 2006 and 2016, from 22 urban and 58 rural nest sites, involving 101 and 326 nesting attempts, respectively. Prey density, biomass and diversity around the individual nests was estimated using modelled estimates from a national bird census. Urban peregrines produced more fledglings and had a higher overall nesting success (i.e. whether a nesting attempt was successful or unsuccessful) than rural peregrines. Prey density and biomass were significantly higher, and diversity significantly lower, in the urban sites, and explained the variation in reproductive success within both the urban and rural environments. Therefore, urban environments in Great Britain appear to provide peregrine falcons with superior habitats in terms of prey availability compared to rural habitats. We conclude that some apex predators can benefit from urban environments and that urban planning has the potential to benefit biodiversity across many trophic levels.

Nest boxes buffer the effects of climate on breeding performance in an African urban raptor

“…Key aspects for the successful establishment of an urban raptor population are the availability of nest sites and prey [109]. A similarly comprehensive study on the breeding performance of peregrines across urban and rural landscapes [31] suggested that higher prey density in urban areas was the main driver of higher productivity (in terms of breeding success, the number of young fledged in successful nests, and overall productivity including nest failures) in these habitats. However, information detailing breeding phenology-which proved to be a key mechanism for higher productivity in peregrines in our work-was not incorporated in their study.…”

“…First, for specialised predators of birds, city centres can be a source of high prey abundance [30]. This has been quantified in other studies of urban raptors [82], including peregrines in the United Kingdom [31], where avian prey density was found to be higher in urban breeding territories than at rural sites; and Black Sparrowhawks (Accipiter melanoleucus) in Cape Town [19], where higher densities of many avian prey species were found in modified landscapes and urban areas than in more natural habitat types. In urban environments, the diet of peregrines typically consists of relatively few species, particularly pigeons and doves (Columbidae), and passerines (thrushes Turdidae and starlings Sturnidae; [83,84]).…”

“…In this study, we focus on a peregrine falcon (Falco peregrinus, hereafter 'peregrine') population resident on the Cape Peninsula. This is a predatory, cliff-nesting species, with a panglobal distribution, which has colonised many large cities around the world [29][30][31]. Our study population includes pairs nesting on natural cliffs, and pairs nesting on buildings and quarries located in the suburban and urban environments of Cape Town.…”

“…Furthermore, urban birds might be affected differently by climate change than those in more natural habitats, which might be linked to a more predictable food resource within urban environments [37] or to artificial nest sites with a different micro-climate compared to natural nests [38]. In raptors, some species benefit from the accumulation of avian prey in urban areas [19,30,31] which might undergo lower fluctuations than natural prey populations. Another example are falcon species breeding in nest boxes which might be more sheltered against extreme weather events than conspecifics nesting in more open environments such as cliffs [39][40][41].…”

Drawing on nature: a vision of an urban residential street adapted for biodiversity in architectural drawings

“…In Britain, built-up areas host twenty percent of the blackbird, starling and song thrush populations and significant numbers of other species (Gregory and Baillie 1998). Species such as peregrine falcons are choosing to become urban specialists, attracted by the nesting-site potential of tall buildings and ready food supply of feral pigeons (Kettel et al 2019). Further, targeted conservation efforts have prompted increases in urban populations of some bat species (Hayhow et al 2016).…”