Red-cockaded woodpeckers: a relationship between reproductive fitness and habitat in the North Carolina Sandhills

摘要

Understanding the habitat requirements of red-cockaded woodpeckers (Picoides borealis), an endangered species that continues to decline in the southeastern United States, is crucial to successfully reversing this trend. We developed a discriminant function using habitat characteristics within 0.25 mile (0.4 km) of the cluster center as independent variables and a demographic measure of fitness as the dependent variable to model habitat quality for 29 red-cockaded woodpecker groups in the North Carolina Sandhills. The best fit model, which included number of cavities, average diameter of overstory pines, and average understory height, correctly classified 23 of 29 sites. Mean values for good and poor sites were: number of cavities, 6.5 and 3.7; pine diameter at breast height (dbh), 35.0 cm (13.8 in) and 38.1 cm (15.0 in); and understory height, 1.89 m (6.2 ft) and 3.26 m (10.7 ft), respectively. Our management recommendations developed from this study include >=7 cavities/group, average pine overstory >20 cm (8 in) dbh, and average understory height <1.8 m (6 ft) throughout nesting and foraging habitat.