Worldwide bird assemblages across urban-wildland gradients

We gathered presence/absence and abundance data from published studies and
reports for 319 well-characterized assemblages spanning 50 cities from
Africa, Australia, Europe, North America and South America. We focused on
cities with comparable survey data within urban habitats and in nearby
natural habitat. The final dataset contains almost 10,000 records for
1507bird species, 66 of which are introduced (non-native) in at least one
study region. Species abundance per unit area or unit time were available
for 269 assemblages from 42 cities, comprising 1353 species. Following
Newbold et al. (2015), we used published habitat descriptions to
classify the intensity of human use in urban habitats
for each assemblage: (1) highly urbanised environments mainly contain
densely packed buildings with vegetation scarce or absent; (2) moderately
urbanised environments are residential areas with single-family houses and
associated gardens; and (3) little-urbanised environments have few
buildings and abundant vegetation (e.g. urban parks). The habitats outside
the city were assigned to either natural vegetation or rural habitat based
on the description of the habitat given in the source paper. Standardised
survey methods were used across habitats within each region.