Shrub-nesting birds in urban habitats: their abundance and association with vegetation

Shrub-nesting bird species are infrequent inhabitants of urban habitats. Our study identifies their location within urban bird assemblages, quantifies their abundance in an urban ecosystem, and explores their association with vegetation variables. The study design consists of 103 point locations distributed among four types of urban habitat: medium-density residential sectors, low-density residential sectors, urban parks and natural parks. We focused on six shrub-nesting species: Gray Catbird (Dumetella carolinensis), Yellow Warbler (Setophaga petechia), Chipping Sparrow (Spizella passerine), Song Sparrow (Melospiza melodia), Northern Cardinal (Cardinalis cardinalis), and Red-winged Blackbird (Agelaius phoeniceus). Results from the PERMANOVA analysis suggest that the types of urban habitat are significantly different based on bird composition. Shrub-nesting species observed in Montreal were most abundant in natural parks, but some were frequently observed in residential areas. The presence of some shrub-nesting species was, depending on the type of urban habitat, associated with higher abundance of deciduous shrubs, clumps of shrubs or deciduous trees. This was not the case with all shrub-nesting species nor in all types of urban habitat.