A Study on Avifauna at Mt. Iide in Bandai-Asahi National Park

Abstract

The author carried out an investigation on avifauna at Mt. Iide (2, 105 m above the sea level) in the latter part of July of both 1966 and 1967. This study was conducted by the use of road-side census method along the climbing route. Although Mt. Iide is regarded as a subalps from the view point of height, it lacks needle-leaved forests such as the Hondo spruce, Picea hondoensis, Northern Japanese hemlock, Tsuga diversifolia, and Fir, Abies Veitchii, which usually grow in subalpine zone. As this result, the vertical distribution of birds is different from the normal status. For instances, the Honshiu nuthatch, Sitta europeae hondoensis, Japanese willow-tit, Parus atricapillus restrictus, and Japanese coal-tit, Parus ater insularis, which also inhabit in the subalpine zone, were observed only in Siebold's beech zone at the foot of the mountain. The Honshiu tree-creeper, Certhia familiaris japonica, Siberian flycatcher, Muscicapa sibirica, Japanese goldcrest, Regulus regulus japonensis, and Japanese robin, Erithacus akahige akahige, which regularly inhabit in the subalpine zone were not observed. Instead of these species, the Japanese hedge-sparrow, Prunella rubida rubida, that usually inhabits over 2, 000 m, was observed descending to 1, 400 m, and Hedge-sparrow, Prunella collaris erythropygia, which inhabits over 2, 300 m, was discovered even as high as 1, 900 m above the sea level. The Swinhoe's willow-warbler, Phylloscopus borealis xanthodrays, and the Japanese bush-robin, Erithacus cyanurus cyanurus, which are regarded as the indicator birds showing the altitude of 1, 500 m were discovered even at 1, 300 m. The time of the present investigation was not best, because the peak of breeding season of birds had already passed. But, 17 families and 34 species were recorded in July of 1966, and 23 families and 39 species in the same month of the following year. As the result of these two observations, ten orders, 23 families and 44 species of birds could be recorded from Mt. Iide. Among them, the most dominant species were Chinese tree-pipit, Anthus hodgsoni hodgsoni, Swinhoe's willow-warbler, Phylloscopus borealis xanthodrays, and the Japanese bush-warbler, Cettia diphone cantans.