VALUE OF SUBURBAN HABITATS TO DESERT RIPARIAN BIRDS

Abstract

Bird populations were monitored over 20 consecutive months in suburban Tempe, Arizona, to assess the value of this artificial habitat for native riparian bird species.Of 104 species detected, 60 were transient migrants, 25 were permanent or summer residents that probably bred locally, and 19 were winter residents.Total density varied from 1423 to 3237 birds/40 ha; four nonriparian residents (Rock Dove [Columba livia ], Inca Dove [ Columbina inca], European Starling [Sturnus vulgaris ], House Sparrow [Passer domesticus ])comprised from 52% to 72% of the total each month.Compared with nearby native riparian habitats (cottonwood-willow and mesquite), the suburban plots appeared to support significantly higher total bird densities in every month.Ten native species occurred in significantly higher density on the suburban transects than in outlying riparian habitats in at least one season.Overall, 53% of the riparian breeding species, and 85% of the winter residents also occurred in suburban Tempe.Absence of other riparian species from the suburban sites may be attributed either to interference by abundant, urban-adapted species or an inability to exploit nonnative tree species.Other suburban sites containing native willows and cottonwoods support populations of several obligate riparian species not found in Tempe.We suggest that well-vegetated suburban habitats have much potential in mitigating against the rapid loss of native riparian vegetation in the Southwest.