Moles (Mogera wogura kobeae) were caught alive, breeded and observed in a behavioral aspect for the purpose of getting more useful informations concerning reasonable conditions to breed the animal. The observation was prosecuted by varing the volume of mud in the cage. In 18cm of the depth of mud, the mole could dig a complex network of tunnels, nesting and staying in it all day long. In 9cm of the depth of mud, which was rather insufficient for the animal to dig tunnels. The animal, however, stayed in the mud all day long except for the time when it took earthworms on the ground surface. In 3 cm of the depth of mud, the mole could not dig tunnels, and they were obliged to stay on the ground at the corner of the case. In a case of more than 9cm of the depth, the animal was observed frequently to throw out the nose alone on the ground surfaced to breathe.

View full abstract

Selected aspects of postnatal development of young Pipistrellus abramus are presented and summarized. Data regarding development that are available for some other species of bat are compared.

View full abstract

Eleven hundred and thirty-nine voles (Microtus montebelli) were collected in a pasture at Okegawa City in Saitama Prefecture, during October 1975 to March 1977, and reproductive activity was investigated. In the sex ratio, females were always higher than males except for January and April in 1976. The testicle size was maintained over 10mm from spring to fall, but reduced in winter. Pregnancy rate holded over forty percent from spring to fall and generally declined in winter, but it was unexpectedly high in January, 1976. It was suggested that main breeding season may be in spring and fall by the result of examinations on pregnancy rate and embryo number, but this species has an ability to breed all the year round, because the breeding season is so changeable that the pregnant females are found in winter, too. The yearly embryo number was 4.5 in average.

View full abstract

Seasonal fluctuations of population size, activity and activity area of Apodemus speciosus ainu THOMAS were studied by live trapping method in a small stand (0.33ha) of broad-leaved trees, which located in Osatsu, Chitose city, Hokkaido, from April, 1978 to September, 1979.
This species has been reported never to be abundant in Hokkaido, but it was the most dominant species (90%) in the stand. The density of over-wintered population in spring was 30/ha, and density become 90/ha in autumn. The population drastically increased according to the appearance of young in May and June, and then gradually decreased till November. During the one month before snow fall, however it was greatly decreased. Relatively high survival rate (76%) was observed in winter (5 months), and this over-wintered population was slightly decreased before the appearance of young.
In over-wintering and reproductive periods, the activity area of this species was limited within this stand, but it was extended to the surrounding grasslands thereafter. The activity area in this stand was seasonaly changed with relation to plant cover. The activity of mice was indicated by a capture rate and a mean distance of movement. Both the values were significantly small in December, and almost zero in February. The least activities and high survival rate of this species under snow cover might have some relations to its large stock of seed cashe.

View full abstract

An aerial count of sika (Cervus nippon) was taken by using a helicopter “Alouette III” in the area of about 2, 000 ha, Omote-Nikko, Tochigi Prefecture, December 15, 1978, and was examined in accuracy by the result of the ground count. The subalpine selection forests of Tsuga diversifolia and Betula ermanii, and unclosed stands of these trees dominated in the area above 1, 600m altitude. The area below it was covered with unclosed artificial stands of coniferous trees and deciduous forests of Quercus mongolica, Fagus crenata, and Larix leptolepis. The helicopter flew 25 minutes from 9: 40a.m. to 10: 05a.m, at 70-120km per hour and 50-200m above the ground, zigzaging in a strip of 500m width over the area. Thirty-nine deer, 7 female groups and two singles, were counted from the air; 25 of them were seen in the ground count area of 590 ha. On the other hand, 174 deer were counted by a block count method, one of the ground counts, with 11 blocks and average block size of 53ha and taking three hours from 6: 30a.m. to 9: 30a.m. Comparing with its result, the accuracy of the aerial count was estimated at 14.4 percent for the whole area. In the area above 1, 600m altitude, only one deer was seen. In the area below it, however, higher accuracy of 30 percent was obtained.

View full abstract

The investigation was carried out from August 28 to September 13 in 1979, on the dry riverbed of the Tone river in Chiba Prefecture. This riverbed has been used to be a pasture by neighboring dairy farmers and have kept pasture grass such as ochard-grass even now. Accordingly this site is a good habitat for the Japanese field vole (Microtus montebelli montebelli MILNE-EDWARDS) .
The population density was estimated through mark and release method and SUGIYAMA's method in a 50×100m area with an interval of 10m between each trapping points. And the number of voles in this area were presumed to be 560 per 0.5 ha. It was also found that the observed range length of the male was smaller than that of the female, 2.5 and 6.1m respectively in average.

View full abstract