A morphometric analysis of populations of yellow-eyed junco (Junco phaeonotus) in southeastern Arizona

Abstract

I sampled populations of Yellow-eyed Junco from six mountain ranges in southeastern Arizona to test hypotheses about morphological variation in the species. Morphometric variables were obtained from measurements in the field, and from photographic images of the head, wing, and tail. Statistical analyses revealed significant seasonal differences in values of bill-length variables, and sexual dimorphism in wing and tail characters, but not in bill characters. Statistically significant geographic discrimination among samples was found only for bill characters. Mahalanobis' distance values from subsets of bill and tailspot variables correlate most significantly with geographic distances between habitats measured along an arc of higher elevation in the region. These correlations, the lack of significant geographic discrimination for wing and tail characters, and the many extralimital records for the species imply that Yellow-eyed Juncos move between isolated populations, and that this movement tends to follow higher elevations in the region.