Species reintroductions are used commonly as a tool for conservation, but rigorous, quantitative assessments of their outcome rarely occur. Such assessments are critical for determining success of the reintroduction and for identifying management actions needed to ensure persistence of reintroduced populations. We collected 9 years of demographic data on populations of brown-headed nuthatches (Sitta pusilla) and Eastern bluebirds (Sialia sialis) reintroduced via translocation into Long Pine Key, Everglades National Park, Florida, USA. Realized population growth of brown-headed nuthatches was positive in the first 3 years after cessation of translocations (λ2002 = 1.15, SE = 0.13; λ2003 = 1.28, SE = 0.12; λ2005 = 1.32, SE = 0.20) but became negative thereafter (λ2006 = 0.67, SE = 0.10; λ2007 = 0.77, SE = 0.13). Realized growth rate for the Eastern bluebird population did not vary among years and indicated either a stable or a slowly declining population (λ = 0.92, SE = 0.04). Reintroductions were a qualified success; they resulted in the re-establishment of populations of both species, but neither population grew to the extent expected and both remained at risk of extinction.
Keywords: Eastern bluebird; Everglades; Pradel model; Sialia sialis; Sitta pusilla; brown-headed nuthatch; population growth; populations; reintroduction.