Urban noise and surrounding city morphology influence green space occupancy by native birds in a Mediterranean-type South American metropolis.

Urban green spaces provide natural habitat for birds in urban landscapes, yet the efects of noise and
surrounding urban morphology on bird community structure and distribution are not well understood
in Latin America, the second most urbanized region in the world. Santiago of Chile is the single city
belonging to the Mediterranean ecosystem in South America and is subject to extensive urbanization
as seen throughout Latin America. We examined the role of 65 urban green spaces—6 large urban
parks (PAR) and 59 small green spaces (SGS)—in harboring native birds during winter 2019, analyzing
the quality of green areas in terms of vegetation (i.e. NDVI, native vegetation, and tree cover),
exotic bird species, noise levels, and surrounding urban morphology (i.e. building height and cover).
Signifcantly higher noise levels were detected in SGS, along with signifcantly greater exotic bird
(n= 4) richness and abundance than PAR, which possessed signifcantly greater native bird (n= 25)
richness and abundance. Native birds were more abundant than exotic birds in green spaces with
average noise levels< 52 dB and average NDVI> 0.5. Occupancy models indicate that green space
occupancy by 50% of modeled native bird species was infuenced by maximum noise levels, playing a
larger role than vegetation (30%) and urban morphology (0%). We stress the importance of developing
networks of large green spaces in rapidly urbanizing regions, with abundant tree cover, surrounded
by smaller urban morphology, and regulating noise levels to ensure the conservation of native bird
communities in cities, particularly those that are threatened.