Effects of Muscle Biopsy on Survival and Breeding Success in Indigo Buntings

Abstract

Breeding Indigo Buntings (Passerina cyanea) were sampled by pectoral muscle biopsy for electrophoretic analysis, and their breeding success and survival were compared with buntings that were only handled and color-banded and with buntings banded in an earlier year. Behavioral and reproductive comparisons showed little difference in males or in females among the three groups. First-year males were more likely to disappear (and presumably to disperse to a new breeding site) after being caught and biopsied before breeding than after being caught and only marked. Mating and fledging success of breeding buntings was not affected by biopsy or by capture and marking. Annual survival of adults was independent of biopsy. Nestling buntings survived to fledging equally well in biopsied and in banded broods, but were less likely to survive when their mother was netted near the nest than when she was not, due to predation. Buntings biopsied as nestlings returned and bred in the study area but at a lower incidence than control buntings banded as nestlings. Muscle biopsy appears to be a nondestructive technique that is compatible with most aspects of long term population studies of small songbirds.