1. By the surveys at three different forest regions, namely Takizawa, Asahikawa and Shigahighland, it was proved that cloudy or rainy weathers respectively affected the census records of every bird species to the same degree (Table 1, 2). This result coincides with that of Fuji Area (Yui 1974, 1977). 2. Bad weather conditions and reduced ratios of the census effectivity show a good correlation (Fig. 1). 3. A sudden change in weather, such as from rainy to clear or from clear to dense cloudiness, has increased the census effectivity to 27.4 relative percent on the average.
1. In the linetransect census data taken at Takizawa and Asahikawa Area, there were no significant differences between the specific relative dominance values calculated from the author's data and that of well-trained young observers (Table 1). This result coinsides with that of Fuji Area (Yui 1974). Namely, these results mean that the census effectivity of every species differs to the same degree between two observers, so long as whose abilities of hearing and seeing are not inferior. 2. The census effectivity of each species was calculated with 95% confidence limit for every two observers in two Areas (Table 2). The majority of the specific census effectivities show the same trend of difference between two observers, although there are almost no significant differences. The differences will become more clear and will converge to the same degree between observers, if more times of census were taken. 3. The levels of census ability of many observers were calculated with relative value against the author's ability, using total recorded numbers of birds per one census standardizing various factors (Table 3). The levels of such observers as well-trained and having normal hearing and seeing ability show about 90±10(%) relative value. 4. To get an accurate estimate of bird density, it is desirable to measure the level of census ability of each observer. But if the error about is 10% permitted, there is no need to measure it, when observer has normal ability in bird census work.
1. The present survey consists of the records of birds sighted or collected in Jeju Island from December 1972 to December 1976; particularly, of the result of the bird censuses conducted in 3 winter seasons and 1 summer season. 2. The number of birds hitherto sighted and recorded in Jeju Islands is 198 species and subspecies, and the number of birds either sighted or collected through the present survey is 77 species. Of these, the details noteworthy are as follows: 1) One bird species of Japanese Green Pigeon, Sphenurus sieboldii sieboldii (Temminck), which was hitherto unrecorded has newly been added to the list of the Korean birds. 2) Eight species of birds have newly been sighted in Jeju Island, which have subsequently been added to the list of birds of Jeju Island. 3. During winter seasons, birds censuses were conducted three times in the area of Jeju City via Seongsanpo to Seogwipo that is the east side of Jeju Island and two times in the area from Seogwipo via Moseulpo back to Jeju City that is the west side of Jeju Island. The total number of the birds sighted during the winter seasons is 7, 289 individuals of 58 species. The number of individual birds and species in each area and year are as follows: (Cf. Table 6, Fig. 9.) The area of Jeju City via Seongsanpo to Seogwipo 1) December 31, 1972…635 individuals of 25 species 2) January 18, 1974…4, 38 individuals of 33 species 3) December 3, 1976…508 individuals of 28 species The area of Seogwipo via Moseulpo to Jeju City 1) December 31, 1972…248 individuals of 16 species 2) January 19, 1974…1, 178 individuals of 26 species The area of Seogwipo via 5.16 Cross Road to Jeju City 1) December 3, 1976…174 individuals of 7 species As shown above, in the bird censuses conducted six times during the winter seasons, a total of 7, 289 individuals of 58 species were sighted. Species dominance shows Carrion Crow (32.14%) which is the most dominant, followed by Spotbill Duck (16.51%), Wigeon (7.11%), Meadow Bunting (6.05%) and so on. (Cf. Fig. 9.) 4. In the summer season, only one bird census was conducted in the area of Jeju City via Mt. Hanra to 5.16 Cross Road on July 29, 1973. The number of birds sighted in this area is 274 individuals of 22 species. Species dominance shows Bush Warbler (23.35%), which is the most dominant, followed by Great Tit (18.97%), Blue Flycatcher (11.67%), Greenfinch (10.21%), Crowned Willow Warbler (8.75%) and so forth. (Cf. Fig. 10.) 5. The sum total of the birds sighted or collected in winter and summer surveys conducted by the authors in Jeju Island from December 1972 to December 1976 is 7, 795 individuals of 77 species. The most dominant species among these is Carrion Crow (30.13%) followed by Spotbill Duck (17.12%), Wigeon (6.65%), Meadow Bunting (5.59%) and so on. (Cf. Fig. 11.)
Surveys on birds were carried out in four types of habitats, deciduous broad-leaved forests, young conifer plantations, cultivated fields and residential areas at Shintoku, Tokachi District, south-eastern Hokkaido from 1976 to 1979. A total of 76 species of birds were recorded in the study areas. Of them Charadrius placidus was recorded for the first time from Tokachi District. In the deciduous forest of Shintoku-yama 60 species of birds were observed. Dominant species were Phylloscopus occipitalis, Ficedula narcissina, Parus palustris and P. major in summer and were Parus palustris, Sitta europaea, Pyrrhula pyrrhula and Corvus macrorhynchos in winter. The avifauna of the deciduous forest along the Sahoro River was similar to that of the forest of Shintoku-yama. In young conifer plantations 17 species of birds were found in summer. Lanius bucephalus, Emberiza cioides and Uragus sibiricus were dominant species there. The avifauna was remarkably poor in comparison to that of deciduous forests above mentioned. In the cultivated field 30 species of birds including some forest birds were observed because of presence of woods and shelter-belts in the area. Passer montanus was the most abundant, and then Streptopelia orientalis, Emberiza spodocephala and Corvus corone were dominant species. In the residential areas only Passer montanus was dominant. There was a tendency that the species diversity was high in deciduous forest, and was low in young plantations and the residential areas.