Graphical abstract Representation of the outcomes of our study, highlighting some of the taxonomic and trait-environment relationships observed across the streetscape of the southern region of Belo Horizonte (Minas Gerais, Brazil). For example, noisy streets, located in regions with reduced green cover, tall buildings, low number of trees, and distant from urban parks are inhabited by a lower richness of large-bodied bird species, mostly omnivorous, exploiting upper vegetation strata, and with smaller clutch sizes. Non-native species are also favored by these highly urbanized sites. On the other hand, streets in residential neighborhoods, with reduced traffic noise, surrounded by higher proportions of green cover, higher number of trees, and near urban parks, are occupied mostly by native and small forest specialist bird species with larger clutch sizes that can exploit lower vegetation strata to forage. This figure has been designed using resources from Freepik.com. Display Omitted

Highlights • We assessed bird traits-environment relationships across a tropical streetscape. • Environmental attributes presented diverse relationships with species and traits. • Mostly noise and green cover modulated birds’ functional and taxonomic compositions. • We observed streets with similar community profiles shaped by environmental conditions.

Abstract The urbanization process leads to changes in bird communities’ taxonomic and functional compositions. Highly urbanized areas generally exhibit a reduced number of bird species sharing few functional traits. However, most urban bird studies focused on vegetation patches in temperate cities. In this study, we investigate how urban environmental attributes – noise, height of buildings, and urban vegetation characteristics – modulate species occurrences and the distribution of functional traits across the streetscape of a tropical metropolis. We predicted diverse trait-environment relationships, but that highly urbanized contexts (e.g., noisy streets with tall buildings) would be mostly occupied b,y a lower number of species sharing generalist traits. We also predicted to observe streets with similar community composition (profiles) shaped by environmental conditions and interspecific interactions. We applied hierarchical modelling of species communities as a flexible framework for analysis of community data. We observed that, increased noise exposure and reduced green cover were negatively related with species richness due to their negative relationships with most species’ occurrences. On the other hand, larger number of trees and higher proportion of green cover presented mostly positive relationships with occurrences, and thus with species richness. Throughout our streetscape, community composition was highly heterogeneous and similar conditions led to similar profiles. For example, noisy streets may favor the presence of omnivorous and large-bodied species, while wooded streets may allow for the presence of smaller-bodied forest specialist species that exploit lower vegetation strata. Our results indicate that streetscapes may have the potential to harbor functionally and taxonomically diverse bird communities.