In tree squirrels, nests have important functions as places for breeding, sleeping, hiding, resting, and social behavior. However, few quantitative studies have been performed on the various functions of nests in the field. In the present study, we built a nest box equipped with a video camera in the field, and quantified the frequency of each behavior in nest use of Japanese giant flying squirrels (Petaurista leucogenys). Three nest boxes were set in a forest in Hachioji City, Tokyo, and a total of 3,549 days were recorded on video from February 2010 to May 2014 using the motion detection function. The percentage of days the flying squirrel used the nest boxes was 33.8%. The total number of visits was 2,114 times. Although flying squirrels used the nest box for roosting (639 times) and raising young (207 times) in daytime, they also frequently used it at night; for example, peeping (238 times), patrols (283 times), dropping in (260 times), sleeping (294 times), and raising young (193 times). The nest use at night was suggested to have three functions : exploration, rest, and breeding. Flying squirrels use the nest frequently for various purposes throughout the year, not only during the day but also at night.

Camera trapping helps estimate wild animal density and enables efficient and continuous monitoring of wild animal populations. In this study, we used the random encounter and staying time (REST) model to estimate the population density of hares (Lepus brachyurus) and compared the results obtained by the fecal pellet counting (FPC) method. The average population density estimated during the survey period was 6.25/km² using the FCP method and 0.68/km² using the REST model. The reason for the discrepancy between the two methods is that the population density of the hare was relatively low in the study area, and the FPC method was strongly influenced by fecal mass. In addition, the measured values for each method differed depending on the environmental category. In the future, it is necessary to compare the results of studies using the FCP method and REST model at the same place while considering the vegetation environment in a high population density of hare.

Population management and feeding damage control of the sika deer are necessary to prevent damages to the forest ecosystem in the mountains. To determine the impact of human activities on the daily activity of the sika deer, we set infrared cameras near the mountain trails and in the forests from June to November 2019, in mountains in the Tokachi region, Hokkaido, Japan. The activity of the deer was high near the mountain trail at night, twilight and dusk, and was high in the forest in the daytime, twilight and dusk. These findings revealed that the daily activity of the sika deer in the mountains was affected by human activities.

Muridae inside zoo might cause infections in both the animals and visitors. Therefore, it is necessary to reveal the distribution of Muridae for their control. We conducted a trapping survey from June to November 2019 in Obihiro Zoo, Hokkaido, Japan, and captured seventy-four Myodes rufocanus, thirty-three Apodemus speciosus, and thirteen Rattus norvegicus. These species were captured every month (except for R. norvegicus in September), and breeding females of M. rufocanus and A. speciosus, were recognized. Therefore, these species would enter or settle constantly in the zoo. M. rufocanus and A. speciosus showed a preference of green space for feeding and sheds for hiding.