Comprehensive information on prey availability and diet composition is important to formulate effective conservation strategies. Data on these of large apex predators, the tiger Panthera tigris, leopard Panthera pardus, and dhole Cuon alpinus, are deficient in Kalakkad-Mundanthurai Tiger Reserve, India, which harbors low prey density. Therefore, we investigated how these predators coexisted by partitioning limited food resources. We found that prey selection and activity patterns differed among predators. The leopard (D [Jacobs' preference index] = +0.916) and dhole (D = +0.937) preferred the Indian chevrotain Moschiola indica, whereas the tiger preferred the gaur Bos gaurus (D = +0.937). Biomass of tiger's diet mainly consisted of the gaur (75%). In the dhole, the Indian chevrotain and sambar Rusa unicolor together contributed 91% of biomass, whereas 79% of leopard's biomass was contributed by the Nilgiri langur Semnopithecus johnii and the Indian chevrotain. The leopard and dhole had the highest dietary overlap (O_jk [Pianka Index] = 0.46). The highest activity overlap was found among the leopard, Indian chevrotain, and sambar. The leopard and dhole would compete for the Indian chevrotain, although the competition may be avoided by different activity patterns. Managements of the Indian chevrotain and gaur are critical for conserving large predators in the region.

In the early 1980s, the European mink (Mustela lutreola) was introduced on Kunashir [Kunashiri] Island in the Kuril [Chishima] Islands in order to preserve it in a region where its main competitor, the American mink (Neovison vison), is absent. We present records of the European mink on Kunashir in 2014–2021. In 23 cases, mink footprints were recorded on the snow or on sandbanks; in other nine cases, the animals were recorded visually or using camera traps. Camera trap photos reliably confirm the existence of a European mink population far from its severely contracted native range. The data were used to compose the dataset “Database of the European mink [Mustela lutreola (Linnaeus, 1761)] occurrence on Kunashir Island” that was transferred to the open international repository GBIF.

In response to severe vegetation degradation caused by sika deer in Japan, it is important to understand the habitat use trends of the sika deer and sympatric Japanese serows to promote the management and conservation of both species and their habitats. This study used camera traps to examine the trends of habitat use of the two sympatric ungulates in the Kuraiyama Experimental Forest (KEF) at Gifu University. We set camera traps at 20 sites and evaluated the number of individuals photographed for three years. Additionally, we surveyed several environmental factors around the camera trap sites to determine the relationship between species prevalence and habitat features. Both species were photographed at all sites, and some habitat use trends were observed. The deer used the west side of the valley, whereas the serows used the east, with clearer trends further observed in summer. Both ungulates avoided snow cover in winter and used steeper slopes and ridges in several seasons. With the current increase in the deer population, niche overlap between the two species may occur in the common place preferred by both species; therefore, careful monitoring of their relationships and their changes should be continued in the future.

This study illustrated body temperature (Tb) fluctuation during reproduction and discussed the effectiveness of measuring Tb for predicting the reproductive profile of female Apodemus speciosus both under laboratory and field conditions. Tb fluctuation was monitored for four breeding events in the laboratory and for three in the field. Individual variation in Tb fluctuation during reproduction was larger in the field than in the laboratory, while its temporal pattern was clearer in the field than in the laboratory. Tb fluctuating patterns according to the progress of the reproductive stage were similar between the laboratory and the field. Daily mean Tb increased after the start of pregnancy, decreased during late pregnancy, rapidly increased after parturition, and remained higher through the lactation period. In particular, the following three characteristics should be apparent indices of parturition: increase of daily mean Tb and daily minimum Tb in early pregnancy, decrease of daily max Tb and daily mean Tb in late pregnancy, and increase of daily max Tb at the day of parturition. These results indicate that implanting small-sized loggers enables us to obtain a representative pattern of Tb fluctuation and to predict the reproductive profile of female A. speciosus, both under laboratory and field conditions.

We explored the genetic diversity and population genetic structure of an invasive alien species, the raccoon Procyon lotor, which was introduced into the Shikoku Island of Japan, using sequences of the mitochondrial control region and 10 polymorphic microsatellite loci. In 80 individuals examined, we detected two genetically divergent haplotypes, indicating that two maternal lineages had been introduced into Shikoku Island. Population clustering analysis suggested the nonexistence of genetic structure in the area. The relatedness network showed that the raccoon population in Shikoku Island consisted of closely related individuals. The genetic diversity of the Shikoku raccoon population was lower than that in the native range. These results and a prior report indicate that the Shikoku raccoon population is likely to have expanded from small numbers of founders originating from an initial invasive population. Raccoon captures outside Kagawa are decreasing, although past expansions into Tokushima and Ehime suggest that there are no geographical barriers among these areas. Therefore, action should be taken to prevent any re-expansion of the raccoon population in Kagawa. Intensive monitoring and the elimination of dispersers from Kagawa, as well as effort to eradicate potential source populations for expansion in Kagawa, are needed.

The domestic cat Felis silvestris catus is known to be one of the most notorious invasive alien predators. Seabirds are typical taxonomic groups that have been impacted by free-ranging cats on islands, and their headless carcasses are frequently observed. We conducted genetic predator identification of the carcasses of streaked shearwater Calonectris leucomelas and described their characteristics on Mikura Island, Japan, where free-ranging cats were blamed for the recent rapid decline of the shearwater population. Eight carcasses of streaked shearwaters were found in the survey. Genetic analysis of swab samples from scarred tissues of the carcasses detected cat DNA and identified cat predation on six out of eight carcasses. All six cat-positive carcasses were headless or almost headless with the head and body faintly connected by esophagus and trachea, several of which were missing their intestines. We describe the conditions of these headless carcasses, noting the main characteristics that could lead to suspicion of cat predation. To the best of our knowledge, this is the first genetic predator identification using seabirds, and may make more stakeholders aware of the reality of cat predation worldwide. On Mikura Island, we expect that this evidence will contribute to the development of systematic cat management.

オオミズナギドリの首なし死骸はネコの捕食によるものだった：遺伝学的捕 食者検出によるエビデンス．イエネコ Felis silvestris catus は，最も有名な侵略的外来捕食者の一つとして知 られている．海鳥は，島嶼においてイエネコの影響を受けてきた典型的な分類群であり，首のない死骸が頻 繁に観察されることがある．本研究では，御蔵島において，イエネコによって近年個体数が減少していると 言われているオオミズナギドリ Calonectris leucomelas の死骸を対象に，遺伝的捕食者検出を行い，さらに死 骸の特徴を明らかにした．今回の調査では，オオミズナギドリの死骸を 8 個体分発見した．死骸の傷口から 採取したスワブサンプルの遺伝子分析により，8 つの死骸のうち 6 つでイエネコの DNA が検出され，イエ ネコの捕食が確認された．これら 6 つの死骸はすべて頭がないか，頭がかろうじて食道や器官で胴体部とつ ながったほぼ首なしという状態で，そのうちのいくつかは消化管も消失していた．本研究では，この首なし という死骸の状態について，イエネコの捕食を疑うことができる主な特徴として提示する．我々の知る限り， 本研究は海鳥を対象とした初めての遺伝的捕食者検出の事例であり，これにより世界的なイエネコの捕食の 実態が，より多くの関係者に認識されるようになるであろう．さらに，この遺伝学的エビデンスが御蔵島に おける本格的なイエネコ対策の展開に貢献することも期待される

Based on mitochondrial cytochrome b gene sequences, we report representatives of the Lineage IV of Rattus tanezumi (Rodentia: Muridae) from Miyakojima, Taramajima, and Yonagunijima Islands in the southern Ryukyus as the first record of the lineage from Japan. The new record of Lineage IV provides an addition to the mammal fauna of Japan essentially at the species level. Accordingly, the genus Rattus in Japan consists of five species: R. rattus, Lineage II of R. tanezumi, Lineage IV of R. tanezumi, R. norvegicus, and R. exulans. The Miyakojima–Taramajima and Yonagunijima samples of the Lineage IV had discernible genetic differences, suggesting different origins. From Miyakojima Island and Kojima Island (an islet close to Miyakojima Island). We also found Lineage II of R. tanezumi, indicating that the two lineages coexist on Miyakojima Island. Morphological comparisons of these Lineage IV and Lineage II specimens suggest a greater molar length in Lineage IV than in Lineage II, and differences in the foramen magnum shape. Future detailed studies on genetic structures, morphological characteristics, and distribution of Lineage IV and Lineage II rats in the southern Ryukyus are needed to clarify their evolutionary history.