By means of protein electrophoresis on 23 loci (15 enzymes), genetic variation and differentiation among eight East Asian Titmice (family Paridae, genus Parus), two long-tailed tits (family Aegithalidae, genus Aegithalos), a nuthatch (family Sittidae, Sitta) and Bearded Tit (family Paradoxornithidae, genus Panurus) were analyzed. A genealogic dendrogram is constructed by the UPGMA method, using genetic distances among the species. The results of the present study suggests that the East Asian Parus species investigated can be divided into four groups, i.e., groups consisting of (1) Parus montanus, (2) P. ater, P, venustulus and P. varies, (3) P. major and P. monticolus, and (4) P. spilonotus and P. holsti. P. spilonotus seems to have a close relationship to P. holsti, but distant relationships to P. major and P. monticolus. Aegithalos, Sitta and Panurus are relatively closely related to each other, whereas the Parus species are shown to have a family level genetic distance in the Passeriformes.
In this study, we could not get enough samples of some species (espe-cially P. montanus and P. spilonotus). And since we obtained samples from dealers, there are some possibility that samples were collected from only one population of each species. The data of other samples from several populations and that of other species are needed to determine the phylogeny of the East Asian Parus species.