USE OF JUVENAL PLUMAGE IN DIAGNOSING SPECIES LIMITS: AN EXAMPLE USING BUNTINGS IN THE GENUS PLECTROPHENAX

Juvenal plumage is largely overlooked in systematic studies of closely related species. Because juvenal plumage is worn for such a brief time, and perhaps because collectors do not realize that this plumage is useful in systematic studies, specimens in this plumage tend to be rather rare in collections. Our results suggest that juvenal plumage can be useful for examining species limits, and an effort should be made to fill this collection gap. By analyzing this plumage between subspecies and putative species, we can obtain a relative scale for defining species limits using the associated informative characters. Quantifying these differences using spectrophotometry allows for rigorous statistical analyses of differences and potential biases. Analysis of juvenal plumage in other groups should also be considered useful in determining species limits, especially when adult plumage characters are only slightly different or equivocal between populations.

ACKNOWLEDGMENTS

This work was supported by the National Science Foundation (NSF OPP-9725154) and the University of Alaska Museum. We thank the staff of the U.S. National Museum for specimens loaned and the Alaska Maritime National Wildlife Refuge for logistical support and permits to work on St. Matthew Island. We also thank D. W. Shaw for taking photographs. Valuable comments were provided by R. T. Brumfield, D. D. Gibson, M. J. Lelevier, J. D. Maley, K. G. McCracken, M. J. Miller, L. E. Olson, C. L. Pruett, and an anonymous reviewer.

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