A predictive model of wetland habitat use on Guam by endangered Mariana Common Moorhens

Abstract

Mariana Common Moorhens (Gallinula chloropus guami) were present in 21 of 33 wetlands examined on Guam. Stepwise logistic regression identified two variables (wetland area, percent cover of emergent vegetation) that distinguished between moorhen presence or absence at a wetland. The predictive equation correctly classified 86% of the wetlands with moorhens, but only 50% of the wetlands without moorhens. The average number of moorhens at wetlands was not influenced by the amount of emergent vegetation cover. Moorhen presence at smaller wetlands with less cover of emergent vegetation may not be an indication of preference for this type of habitat on Guam. Instead, moorhen presence was likely based on wetland availability. Enhancement and management of larger natural wetlands would increase the amount of seasonal and permanent habitat available to moorhens and provide resources for more than one breeding pair of moorhens per wetland.