The distribution and abundance of the exotic and native urban avifauna in Miami-Dade County Florida

Abstract

Southern Florida is experiencing an unprecedented population expansion of several exotic avian species. To understand the impact of introduced species on the native bird community, I censused two transects that spanned older, urban, closed canopy (ca. 60 yr.- old) to more recent (\u3c 20 yr-old) suburban, open canopy habitats in Miami-Dade County, Florida for a 12-mo period. The recently introduced Eurasian Collared Dove (Streptopelia decaocto) was the most abundant species (92.7 birds/km2), but density varied across transects with lowest density (2.87 birds/km2) in older-growth habitat compared to the maximum density (210 birds/km2) in young habitat. The European Starling (Sturnus vulgaris) was second in abundance at 79.1 birds/km2. The Boat-tailed Grackle (Quiscalus major) was the third most abundant species (67.5 birds/km2). The Mourning Dove (Zenaida macroura), considered to be threatened by the Collared Dove (Simberloff et al. 1997, Schmitz and Brown 1994), was the next most abundant at (66.1 birds/km2). The House Sparrow (Passer domesticus) was evenly distributed and consistently averaged 52.5 birds/km 2. The Rock Dove (Columba livia) averaged 39.7 birds/km2 and was absent from older areas with high canopy cover. The Northern Mockingbird (Mimus polyglottos) averaged 34.5 birds/km2 and was the most evenly distributed species in the study area. The Blue Jay (Cyanocitta cristata) was also evenly distributed and averaged 16.9 birds/km 2. The introduced Monk Parakeet (Myiopsitta monachus), considered an agricultural pest, averaged 9.70 birds/km 2, with peak abundance in recently developed habitats (22.8 birds/km2) and none observed in older urban areas. The Red-bellied Woodpecker (Melanerpes carolinus) was consistently observed at 6.07 birds/km2. Introduced species are a numerically dominant component of the urban avifauna in Miami, composing over 53% of the resident bird population