Morphometric variation in the Pericrocotus minivets of northeast Asia

Abstract

The status of the two taxa of Pericrocotus minivets recorded in northeast Asia (divaricatus and tegimae) is controversial, with some authorities considering them subspecies but most considering them full species. Therefore, in order to further understand the status of these taxa and to elucidate geographic patterns of morphometric variation in their populations, I examined 85 museum specimens collected from Japan and neighbouring territories. The results confirm that morphometric differences exist between the two taxa, the northern migratory divaricatus and the southern sedentary tegimae, and that these differences are statistically significant. However, the results also reveal that there is considerable geographic variation, in terms of wing length, between populations within each taxon. In particular, the population of tegimae resident in Kyushu, Japan, has significantly longer wings than populations further south in the Nansei Shoto; and populations of divaricatus from the Korean Peninsula and adjacent regions have smaller beaks and shorter wings than the population in Honshu, Japan.