Further Notes on the Morphological Differences between Parus palustris and P. montanus

Abstract

In the previous paper we showed the morphological differences between the Marsh, Parus palustris, and the Willow, P. montanus, Tits under the urgent necessity of claryfying the identification criterion (Abe & Kurosawa 1976). It seems that this paper is still a useful guide for Japanese ringers, although there was careless error in the description on the longest and shortest tail feathers and the sample sizes were rather small. In the present paper larger samples taken at Hokkaido in seven autumns of 1975-81 are treated. The measurements are given in Tables 1-5; these percentage-distributions are shown in Figures 1-7. The ranges of all measurements of two species were overlapped, however these two species could be separated most clearly in the bill depth, the ratio of bill depth to exposed culmen and the graduation of tail. There was considerable variety in the longest and shortest tail feathers. It seems probably because the growth of juvenile tail feathers and the number of feathers renewed in postjuvenile moult are irregular and inconstant (Abe & Kurosawa in prep).