Recovery of the Galápagos rail ( Laterallus spilonotus) following the removal of invasive mammals

Abstract

Rails (family Rallidae) are vulnerable to the impacts of invasive mammals, and this is particularly true for species on oceanic islands. The endemic Galápagos rail ( Laterallus spilonotus) is no exception; previous studies suggested that Galápagos rail populations were heavily impacted due to predation by pigs ( Sus scrofa) and habitat degradation by goats ( Capra hircus). Following recent conservation actions that have eradicated pigs and goats from Santiago Island, changes in rail abundance were observed. Estimated densities have increased by over an order of magnitude between 1986/1987 and 2004/2005. Limited data on rail densities from two additional islands over the same time period provide further support to the notion that the eradications spurred recovery. On Fernandina Island, where there is no history of invasive mammals, rail density increased slightly between 1986/1987 and 2004/2005. In contrast, on Isabela Island where invasive mammals were present both in 1986/1987 and 2004/2005, rail densities declined at one site between those two time periods. While the Galápagos rail is vulnerable to invasive mammals, the observed changes following goat and pig removal are encouraging for Rallidae conservation.