Diel rhythmic activity, foraging site utilization and food habits, of the Black-crowned Night Heron (Nycticorax nycticorax) was studied in its breeding season, at colonies on the border of the Tsugaru Plain, northern Japan. During the non-breeding season they were nocturnally active, but in the breeding season they foraged both in the daytime and at night.Their main foraging sites comprised two habitats, i.e. paddyfields with irrigation ditches, and rivers. In the latter habitat, fishways and dams were most frequently utilized. The Night Herons chiefly fed on fishes, Japanese Loaches (Misgurnus anguillicaudatus) in particular. The results of comparisons of diet composition collected in the morning with that collected in the evening, and of distribution frequency of the directions in which the herons departed from the colonies and from which they returned to the colonies around sunset, suggested that the herons switched their foraging habitats between day and night; daytime in rivers and nighttime in paddyfields. The pattern of activity of the prey fishes in paddyfields is known to be nocturnal, in contrast to the diurnal activity of the river fishes. Therefore, the profitabilities of these two habitats change rhythmically in a day. This seems to be the reason why the herons switched their foraging habitats between day and night.

View full abstract

Bird community and vegetation structure were surveyed in a forest, dominated by Fagus crenata, Acer shirasawanum and Picea jezoensis, with a high density of sika deer Cervus nippon in Ohdaigahara, central Japan, during the breeding season from 1994 to 1998. The average density and number of species were 409 pairs/100 ha and 20 species, respectively, and were stable throughout the five years. The most dominant species was Parus ater, followed by Parus major, Sitta europaea, Troglodytes troglodytes and Tarsiger cyanurus. Birds nesting in undergrowth were absent and those in low-canopy were low in density and number of species. This result was related to the small amount of foliage for their nesting sites, which were overgrazed by deer.

View full abstract

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.

View full abstract

Inter-annual variability of the numbers of Anser fabalis middendorffii (AFM) in northern Shiga Prefecture was investigated during 1982-97 in relation to the temperature, snow-depth and water level of Lake Biwa.Statistical analysis showed: 1) a strong negative correlation between the numbers and winter temperature in northern Shiga Prefecture, in which the temperature represented the average temperature and snow cover extension in Japan; 2) a negative correlation between the numbers and water level; and 3) abnormal heavy snow fall in Shiga Prefecture, such as in 1983/84, caused a decrease of the numbers. The results indicate that nation-wide cold winter with extensive snow cover induced southward migration of AFM to increase their numbers in Shiga Prefecture. Besides, due to poor feeding conditions, the AFM moved to the neighboring inland areas in case the water level of Lake Biwa increased.

View full abstract

Escaped Hwamei Garrulax canorus have naturalized in northern Kyushu. The distribution and the habitat of G. canorus were analyzed via questionnaires sent to birdwatchers in 1995. G. canorus were distributed mainly in the central part of Fukuoka Prefecture, and their distribution reached the eastern part of Saga Prefecture and the western part of Oita Prefecture. The oldest record of G. canorus was in the first half of 1980's. The reports of the new sightings of G. canorus increased in 1990's. Thus, its distribution seems to be spreading. The main habitat of G. canorus was the bush layer and the ground of forests on low mountains and hills.

View full abstract