Most Rubus species (Rosaceae) are pioneer shrubs that quickly invade and increase when open conditions form in suitable habitat, and are typical endozoochorous plants, whose fruits are consumed by a variety of birds and mammals. Quantitative seed dispersal is characterized as the number of fruits removed from plants by wildlife. By use of camera-traps, we recorded fruit removal from three species of Rubus (R. hirsutus, R. palmatus, and R. crataegifolius), and identified the wildlife species of quantitatively effective seed dispersers in a cedar plantation. The study was conducted from May 9 to July 10, 2019, on Rubus that established after thinning in a cedar plantation at the Forestry Experimental Station of Ishikawa Agriculture and Forestry Research Center in Ishikawa Prefecture, Central Japan. Camera traps (Ltl Acorn6210MC) recorded fruit removal by frugivores of 108 fruits on the branches for R. hirsutus, 489 fruits on the branches and 32 fruits on the ground for R. palmatus, and 168 fruits on the branches for R. crataegifolius. Most of the fruits monitored were rapidly removed from the trees for all three Rubus species: 83% of monitored fruits were removed after three weeks. The top species with high fruit removal were Japanese Macaque Macaca fuscata (30.4% of the total number of fruits removed), Japanese Badger Meles anakuma (27.8%), and Brown-eared Bulbul Hypsipetes amaurotis (19.0%) for R. hirsutus, H. amaurotis (59.7%) and M. fuscata (37.4%) for R. palmatus, and H. amaurotis (78.2%) and M. fuscata (20.4%) for R. crataegifolius. The germination rate of R. crataegifolius seeds dispersed by Hypsipetes amaurotis was 3.2% (N=189). Due to the high number of fruits removed, we concluded that these frugivore species are highly effective as quantitative dispersal of these Rubus species. We assumed the effectiveness of the three frugivores as qualitative (germination performance of seeds) seed dispersers because they disperse intact seeds in a dispersal area ranging from tens of hectares to several square kilometers, depending on species.

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The Daurian Redstart Phoenicurus auroreus, formerly considered a winter resident in Japan, is expanding its breeding area. Although this species was originally a cavity-nesting bird, it has been selecting nesting sites in exhaust fan rain covers, with wider openings than birdhouses and mailboxes. To understand the reasons, we compared two types of exhaust fan rain covers, one that birds used and one that they did not, focusing on the view from the nest. As a result, the species was found to use exhaust fan rain covers with significantly smaller vertical viewing angles or solid angles, regardless of the size of the opening. In addition, exhaust fan rain covers had the characteristically narrow fields of view from the nest, making it difficult for potential predators to enter the field of view. Therefore, we suggest that the Daurian Redstart used exhaust fan rain covers as nesting sites to avoid detection by predators. Investigating the field of view from the nest using a solid angle is useful for evaluating the nesting site selection patterns.

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Previous studies have shown that the Carrion Crow Corvus corone is more frequently on the ground and at lower heights than the Jungle Crow C. macrorhynchos. However, whether Carrion Crow uses lower heights by choice has not been confirmed. We studied the heights at which the two species were observed in relation to the availability of structures of various heights in the urban environment of Hakodate, Hokkaido. The result showed that Carrion Crow was observed significantly more often at a lower height than Jungle Crow, regardless of the heights of surrounding structures. Two possible explanations of the height choice of Carrion Crow include: 1) it is associated with their habit of foraging on the ground, or 2) a result of interspecific competition between the two species of crows.

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From 1998 to 2018, in four colonies in the southern Kanto region of Japan, 6,807 Great Cormorants Phalacrocorax carbo were banded with color bands for individual identification. During 22 years between 1998 through June 2019, 6,575 sightings of 1,783 individuals were recorded. The number of color-banded cormorants gradually increased from the beginning to the middle of that period, and then decreased in the latter half of the study period. The number of records reported by bird watchers showed a pattern similar to the number of banded cormorants. However, the decrease in the records in the latter half appeared to have been influenced by the decreasing number of reported individuals. The recorded number of cormorants decreased, reflecting the advanced age classes of the banded population. The banded cormorants were reported mainly in Tokyo, Chiba, and Kanagawa prefectures where the birds were initially captured and released, with some reports from distant locations, including Aomori Prefecture to the north and Shiga Prefecture on the Pacific coast of Honshu Island. Therefore, these prefectures were demonstrated to represent the main range of movement for the population of Southern Kanto area. Results gained by these records indicated a need for establishing a strategy to maintain long-term record keeping by observers.

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Using data from two national breeding-bird surveys, the Japan Breeding Bird Atlas and Monitoring Site 1000, we determined the average temperature of forest bird habitats during the breeding season. The mean temperatures of the distribution areas of various bird species (species temperature index: STI) calculated from both surveys were a good match and seemed reliable. However, the values calculated from the Monitoring Site 1000 tended to be slightly higher than those calculated from the Japan Breeding Bird Atlas, which may be due to the smaller number of survey sites in Hokkaido in Monitoring Site 1000. Therefore, STI from the Japan Breeding Bird Atlas seems more reliable as an index. We identified species groups suitable for monitoring the effects of climate change in the future. One is the species group whose distribution area is biased toward warmer regions, and the other is toward colder regions. The former includes Varied Tit Poecile varius, Brown-eared Bulbul Hypsipetes amaurotis, and Japanese White-eye Zosterops japonicus, and the latter includes Japanese Leaf Warbler Phylloscopus xanthodryas and Eurasian Bullfinch Pyrrhula pyrrhula.

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To clarify effects of climate change on birds, we recorded the dates when forest birds began actively singing and analyzed the relationships with temperature and precipitation. Observations were conducted at four forest sites from 2009 to 2021. The mean temperature in May was identified as a factor that influenced the timing of active singing for all five species (Asian Stubtail Urosphena squameiceps, Eastern Crowned-warbler Phylloscopus coronatus, Siberian Blue Robin Larvivora cyane, Narcissus Flycatcher Ficedula narcissina, Grey Bunting Emberiza variabilis). The mean temperature in April was significantly correlated only in Narcissus Flycatcher. The temperature during the most recent period to the start of singing may have had a strong influence on singing behavior. In the case of the Asian Stubtail, precipitation in April had the strongest effect on the date when the species became active. The Asian Stubtail typically forages and nests in the bushes near the ground, so April precipitation, which melts snow cover, possibly has a strong influence on stubtail behavior. Species like Grey Bunting and the Siberian Blue Robin also forage close to the ground, so monitoring the snow cover by interval cameras may be an important additional method of study.

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The acoustic survey is now gaining attention as a method by which to monitor birds. It has advantages over conventional methods, such as point count and line transect methods, because of its low disturbance to natural behaviors. Recent research has addressed development of automatic bird species identification systems using Artificial Intelligence (AI) techniques to actively identify bird calls. Despite a recent increase in research, an effective and systematic procedure has not been identified. To build an automated bird species identification process, we tested multiple methods of sound and image preprocessing with representative machine learning models. The target species was the Grey-faced Buzzard-eagle Butastur indicus, which is a species of raptor categorized as “Vulnerable (VU)” in the Japanese Red List. The sound files included the species’ calls recorded at two different sites. The optimal sound threshold to detect the bird calls, and the sound duration to sample, were identified using a Convolutional Neural Network (CNN) model and evaluating the cross-validation and generalization performance. Alternative methods, including the random forest model and multi-layer perception model, were compared with the performance of CNN. We determined that the optimal method was applying CNN-based classification systems using sounds of 2-3 seconds, detected by the increase of 1-3 dB sound pressure level over the prior 10 milliseconds. The highest F1-score of cross-validation and generalization performance were 0.89 and 0.71, respectively.

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The wintering distribution and the detailed status of presence or absence of the Swinhoe's Rail Coturnicops exquisitus are unknown except for the Kanto region. To confirm the presence of this species, we conducted a call playback survey in shoreline areas along the Pacific Ocean in the central Honshu and Kinki regions (Shizuoka, Aichi, Mie, and Wakayama prefectures) from January 2020 to April 2022. We confirmed the presence of this species at 12 of the 34 sites where we conducted surveys. The species was present throughout the wintering season in these areas, and thus we conclude the area is an active wintering site. The majority of the occupied habitats were wet grasslands established on abandoned rice fields, implying that such environments are important habitats for this species. This species’ habitat is likely disappearing without the potential effects for the species being fully understood, and further research into the habitat status is recommended.

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We monitored the Northern Goshawk Accipiter gentilis at six sites in Japan to determine trends in the number of breeding pairs. In addition, to identify changes in the reproductive performance of goshawks at a wide geographic scale, breeding data was collected from via web form from observers nationwide and were analyzed regionally.

From 2001 to 2021, the number of breeding pairs of goshawks at the six monitoring sites decreased significantly by 2.8%/year. From 2016 to 2021, the proportion of previously-known nests that failed to breed had increased in the Kanto and Chubu regions. Also, a significant decreasing trend in the number of fledglings was observed at 47 nests under continuous survey.

On September 21, 2017, the Northern Goshawk was removed from the list of “Nationally Endangered Species of Wild Fauna and Flora” under the Law for the Conservation Endangered Species of Wild Fauna and Flora. The present results do not point to a direct effect attributable to removal from the list. Our data, however, indicates reduced breeding performance and a decline in the number of active pairs, and we recommend continued monitoring of those parameters.

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Ruddy-breasted Crakes Porzana fusca have secretive behavior and prefer densely vegetated habitats, so there is little information available about the distribution of this species in Japan, especially on Shikoku Island. I used callback survey methods in Kagawa and Tokushima Prefectures on Shikoku Island during the winters of 2016-2018 at 45 sites identified by GIS (Geographic Information Systems) as having generally suitable habitat characteristics. Survey results identified 29 birds at 8 sites in Tokushima Prefecture, and 24 birds at 14 sites in Kagawa Prefecture. A total of 53 birds were identified at 22 sites of the 45 sites investigated.

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We observed a nest of the Daurian Redstart Phoenicurus auroreus and three fledglings at Zao Onsen, Yamagata Prefecture, from June 5 to July 2, 2022. Although the Yamagata Branch of the Wild Bird Society of Japan conducted bird-watching parties in this area until the summer of 2015, there were no records of the Daurian Redstart observations during the breeding season, suggesting that the Daurian Redstart has started breeding in recent years

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In the autumn of 2020, a simultaneous count and one additional survey for Red-crowned Cranes Grus japonensis were conducted in Central-western Hokkaido. Each investigator used a car and drove specified routes in the research area at a designated time on the same day, October 9, 2020. In that simultaneous count, a total of 9 birds (6 adults and 3 juveniles) were recorded. In an additional survey conducted after the simultaneous count, in mid-October, 4 adults and 2 juveniles were recorded. The birds recorded during the additional survey were confirmed to be different birds than those observed during the simultaneous count based on morphological features. As a result, a total of 15 birds (10 adults and 5 juveniles) were confirmed. This survey clarified the population status of Red-crowned Cranes in Central-western Hokkaido, and confirmed that the species is expanding their distribution. This data may be important for the conservation of the cranes, and it is recommended that a simultaneous count in this area be continued at some frequency.

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