Multiscale heterogeneity within and beyond Taipei city greenspaces and their relationship with avian biodiversity

•A within- and beyond-greenspace framework was used to study urban birds in Taipei.•Fine-scale heterogeneity and complex dynamics were found through 5 avian-habitat types.•Isolation effects found only for forest birds; others responded to nearer environs.•Synanthropics and exotics were mostly open-woodland and short-grass birds.•Human preferences in landuse and landscaping affect ecosystems beyond fragmentation.