Consequences of using Conspecific Attraction in Avian Conservation: A Case Study of Endangered Colonial Waterbirds

Abstract

Through the use of conspecific models and vocalizations, populations of conservation concern can be established in locations where limiting factors may be controlled or mitigated, assuming managers can both identify and create high-quality locations. From 2003 to 2008, conspecific attraction was used to establish populations of the state-endangered Forster's Tern (Sterna forsteri) in northeastern Illinois, USA. In 2009 and 2010, similar techniques were used with the federally-threatened Least Tern, (Stemula antillarum) near the confluence of the Missouri and Mississippi Rivers in Missouri, USA. At both locations, managers attempted to control factors that may limit tern reproductive success. While in most cases nesting populations were established, in some cases resulting in the greatest documented reproductive success in the region for decades, nest predation the year after the colonies were established was significantly higher than in the year the colony was established. The establishment of colonies attracted a variety of predators, some of which gained access to the colonies and predated tern nests. Conspecific attraction behavior may be a strategy used by birds to stay “one step ahead” of nest predators, and the repeated use of conspecific attraction by managers may result in individuals nesting at a site with high rates of nest predation. As a conservation tool, conspecific attraction should only be used in situations where nest predators can be effectively controlled.