Fig 1. Study area and distribution of urban areas on the Cape Peninsula, South Africa.

Peregrine falcon nest types were categorised as nest boxes (black), nests on buildings without boxes (blue), in quarries (grey) and on natural cliffs (green); photos: Andrew Jenkins. Note that nest locations are senstive information and were not plotted on the map to protect the species. Distribution of the Peregrine falcons and nearest neighbour distances (NND; n = 779 territory occupation records) in relation to (top) the urban gradient [% urban cover] and (bottom) the increasing population density over years [1989–2014]. Red dashed lines indicates the threshold for the ‘urban subset’, which included all four nest types but was restricted to nest locations with >40% urban cover, and the regression lines.