A comparison of eastern bluebird reproductive parameters in golf and rural habitats
2005
Stanback, Mark T. | Seifert, Megan L.
Analysis of reproductive parameters of birds breeding on golf courses can provide valuable insight into the biological effects of the golf-course environment on wildlife. For 6 seasons (1999––2004) we monitored initiation of breeding, inter-nest intervals, clutch size, brood size, and chick condition of eastern bluebirds (Sialia sialis) in North Carolina with ∼∼150 nestboxes in available nongolf habitat (hayfields, old fields, pastures) and up to 250 on golf courses. Bluebirds nesting on golf courses initiated their first nests an average of 1 day later and laid slightly smaller clutches (4.4 vs. 4.5) than pairs nesting in nongolf habitat. The mean time interval between spring and summer nests was 3.5 days longer for bluebirds on golf courses. Brood size did not differ significantly between golf and nongolf habitat. Nestlings (the shortest-winged chick in each brood) on golf courses were in slightly but significantly poorer condition than those in nongolf habitat. Using 2 independent measures of condition-quality (residuals from a linear regression of mass on wing³, tail symmetry), we found that adults of both sexes breeding on golf courses were similar to those nesting in non-golf habitat. While these adult data do not rule out the possibility that the poorer performance of bluebirds on golf courses was due to settlement of golf courses by inferior birds, they do suggest that a more direct effect is at least as plausible. Similarly, although we cannot rule out direct effects of chemical contamination or human disturbance, the lower abundance of arthropods on golf courses provides a likely mechanism for the slightly poorer performance of bluebirds breeding there.
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