Currently, the number of confirmed locations for Luscinia cyane during the breeding season is decreasing nationwide, while Emberiza variabilis is increasing. Both species are locally observed during the breeding season in the mountains of Shiga Prefecture, but their distribution is not fully understood. In order to confirm the distribution of these species, we conducted a survey of the number of singing males at 48 survey sites in 7 mountain ranges throughout Shiga Prefecture between May and July from 2020 to 2023. As a result, Luscinia cyane was confirmed in 23 survey sites on 5 mountain ranges, and Emberiza variabilis was confirmed in 8 survey sites on 3 mountain ranges. Regarding Luscinia cyane, there was no change in the distribution of mountain ranges compared to records from the 2000s, but a decrease in habitat was suggested for two mountain ranges. Regarding Emberiza variabilis, there are no records of the breeding season before 1990s, so it is thought that the distribution of the breeding season has expanded in recent years.

I investigated changes in the breeding colonies of Great Cormorant Phalacrocorax carbo in Hokkaido from 2001 to 2022. Through literature research and field surveys，a total of 18 breeding sites were identified, including 12 colonies using natural objects and 6 colonies using man-made structure. In 2022, there were a total of nine breeding colonies, including four natural breeding colonies and five artificial breeding colonies. The number of nests increased from 16 in 2001 to 2,558 in 2022. The number of nests in three breeding colonies located from the Sarobetsu Plain to the coast of the Sea of Okhotsk, Penke swamp, Yubetsu river, and Abashiri port, accounted for 92.9% of the total number of nests in Hokkaido. These three colonies have many lakes and marshes within 15km from colony. Natural breeding colonies were more likely to be abandoned than artificial colonies. This was thought to be due to the invasion of terrestrial predators and the death of nesting trees. Great Cormorant in Hokkaido are thought to spend the winter mainly in Honshu. Therefore, in order to effectively manage the cormorant population against fishery damage, it is necessary to continuously and accurately grasp the number of nesting birds in Hokkaido.

Using national wintering bird survey data, we examined changes in the wintering bird fauna in Japan from the 1980s to the 2010s and the factors influencing these changes. We also examined the differences between wintering and breeding seasons by comparing the data with breeding bird survey data. The results showed that wintering birds expanded their distribution area more northward compared to the breeding season from the 1980s to the 2010s. Non-forested ground-feeding birds, shallow-water foragers, and aerial foragers, for which low temperatures and snow cover are thought to be limiting factors in distribution, moved their distribution northward. Arboreal, submerged, and marine foragers moved the northern edge of their distribution northward. Aerial foraging birds moved northward in their distribution as temperatures increased, but other species did not move as far north in their distribution as expected by temperatures. These results suggest that the effects of climate change on wintering birds differ from those during the breeding season and are positive for birds whose distribution was restricted by cold.

We analyzed data from the Tokyo Metropolitan Bird Breeding Distribution Survey conducted in the 1970s, 1990s, and 2010s to describe changes in the bird fauna of Tokyo over 40 years. The distribution of many forest bird species was reduced between the 1970s to the 1990s but expanded and recovered through the 2010s, whereas non-forest bird species showed a decrease but no recovery. There is a correlation between the number of forest bird species and forest coverage, and the forest coverage decreased through the 1990s and increased after that, suggesting that increases and decreases in forest area may have affected changes in the bird fauna. There was a positive correlation between forest coverage and the number of forest bird species present. However, there was a difference between the 1970s and 1990s, when fewer species were recorded than predicted by the equation, and the 2010s when more species were recorded. Tree growth may have contributed to these differences. The distribution of resident birds did not shrink between the 1970s and 1990s, while that of summer birds did. Both groups expanded their distribution in the 2010s, but summer birds did not increase enough to recover their former distribution in the 1970s.

We examined the status of the Gray's Grasshopper Warbler Locustella fasciolata in the area around Shiriyazaki on the Shimokita Peninsula in the northern part of Honshu Island, Japan, which was previously known to be outside of its breeding distribution. We conducted line transects and confirmed that 19 individuals were singing. Using digital voice recorders, we confirmed that they sang from June to August in 2021 and 2022. Considering the oviposition period and when this species leaves its breeding grounds, multiple individuals are likely breeding in the area. Additionally, we conducted song analysis, morphological analysis, and molecular phylogenetic analysis. These analyses confirmed that the captured individuals were Gray's Grasshopper Warblers, specifically the subspecies L.f. amnicola, previously known to breed only in Hokkaido and further north.

We recorded avifauna by listening to live sound broadcasts from Furano, Hokkaido; Chichibu, Saitama; Yamanakako, Yamanashi; and Shiga Kogen, Nagano Prefectures during three months of the breeding season from 2012 to 2024. Of the 81 major bird species, 65 showed no significant trend of increase or decrease. On the other hand, 11 species, such as Varied Tit Sittiparus varius and Eastern Crowned-warbler Phylloscopus coronatus, increased significantly, and five species, such as Japanese Tit Parus cinereus, decreased significantly. In Chichibu, the Community Temperature Index increased over the 12 years, indicating a change to the bird community of a warmer region, while other sites showed no significant changes. Other studies have also shown an increase in the species richness of mainly broad-leaved forests, such as Varied Tit and White-eye Zosterops japonicus, at study sites in central Honshu at elevations similar to Chichibu, suggesting that a significant change in avifauna is currently occurring at elevations about 1000 m in central Honshu.

In the study site located in the middle reaches of a river of Hidaka in Wakayama Prefecture, there was a large-scale rainfall in October 2017, and almost no teal Anas crecca were seen during the wintering season in 2017-2018. Therefore, I examined the relationship between the number of teal, rainfall, and water levels in the autumn migration period from 2014 to 2020, and considered the effects of water levels on the number of teal. During the study period, 70 cases of rainfall period were observed, and in 67 of them, the moving average estrangement rate could be calculated. As a result, it was suggested that a rise in water level above a certain value affects the decrease in the number of teal. In addition, when the water level rose above a certain value, the function of the study site as a foraging or resting place is diminished, and it was thought that teals moved from the study site to other places. And it was suggested that if there is a large-scale rainfall at the time when teals begin to arrive, as in October 2017, Teals may abandon their settlement in the study site, but it is necessary to accumulate more data to verify this.

The number of censuses must be consistent to compare the number of species in bird communities because the cumulative number of species recorded is affected by both the number of censuses and seasons of the censuses. We compared the numbers of bird species and individuals identified from 2,069 route censuses conducted for 10-years in a 1.4 km wooded zone along Tamagawa-josui Canal, Kodaira City, Tokyo, with subsets of those surveys conducted once a month for 10 years, 3 years, and 1 year. Of the total number of species and individuals recorded, the number of bird species were 70.2%, 54.8%, and 41.3%, respectively, and those of individuals were 5.8%, 1.8%, and 0.8%. Although the top 20-30 bird species were consistent in all the surveys, rare species were not recorded by 10-year surveys, low-frequency migratory birds were not recorded by 3-year surveys, and sedentary birds and common migratory birds were recorded by 1-year surveys. The top 10 species in numbers were consistent regardless of the number of surveys and recorded even by 1-year survey. A comparison of data from 36 monthly censuses over 3 years in Kodaira City and the Imperial Palace showed that the numbers of species recorded were 41 in Kodaira City and 67 in the Imperial Palace, respectively. Since 84 species were recorded in the 2,069 censuses in Kodaira City, the numbers of recorded birds are affected by the times of censuses. Therefore, when comparing bird communities, censuses should be conducted throughout the year. One-year censuses can find core species, three-year censuses can discover the major migratory birds, and to find low-frequency migratory birds longer studies are needed. We pointed out that to compare different bird communities, the number of censuses should be aligned.

In crowded urban areas, there are various conflicts between Large-billed Crows and Carrion Crows (hereafter referred to as both species of "crows") and humans, the most common of which is scavenging garbage. Some municipalities are changing garbage bags and receptacles to prevent scavenging, but knowledge of the environment and seasons preferred by crows could be helpful to those efforts. Therefore, we performed a study to determine what areas crows prefer to scavenge and where scavenging occurs. The study was conducted in Asakura, Kochi City, with four routes based on distance from the forest and housing type. A total of 122 garbage stations were selected that were always in use on the combustible-garbage collection days that occurred twice per week. The study period was from May to December 2023, with one route patrolled three times every two hours from 6:00 a.m. to 12:00 p.m. per visit. The survey recorded the number of garbage bags (hereafter called "number of bags"), the type of receptacles, and the surrounding environment (housing type, forest coverage, etc.). In the analysis, a generalized additive model was used in which the presence or absence of scavenging was used as the response variable, and the date of the survey, number of bags, type of receptacles, and surrounding environment were used as explanatory variables. Each location was surveyed for 8 to 11 days (36 days total), and scavenging damage was observed at 36 of the 122 locations. The statistical analysis results suggest that in Asakura there is a seasonal change in scavenging, with a high rate of scavenging in the spring season and a subsequent decrease, that measures taken with receptacles have not been very effective, and that crows may prefer areas with a large number of garbage bags when scavenging.

A Black-winged Kite Elanus caeruleus was recorded for the first time on Hateruma-jima Island, on August 12, 2023. This individual was identified as a juvenile of subspecies vociferus, mainly based on the characteristics of its plumage. The first record of an individual identified as a Black-winged Kite in Japan dates back to an observation on Ishigaki-jima Island in 1995. Subsequently, the first breeding record in Japan was obtained also on Ishigaki-jima island in 2017. However, until now these records have not been reported in scholarly publications, and there is a need to scientifically describe the kites in Japan with a clear identification basis. This is the first academic report based on detailed morphological characteristics with accompanying photographs that this individual belongs to the E. caeruleus and not to another species of the same genus. Over the preceding half-century, the global distribution of this species has undergone a substantial expansion. The kite serves as valuable research subject for the ecological study of range expansion. We hope that studies on the range expansion of this species will include impacts of that expansion on the ecosystem.

We conducted a survey of wintering Swinhoe's Rails Coturnicops exquisitus at 186 wet-grasslands in the Chugoku, Shikoku, and Kyushu regions of southwestern Japan, during the winters of 2021-2022 and 2022-2023. We found 19 individuals at nine sites in Shikoku and Kyushu. Abandoned rice fields were the most important habitats. Almost all rails were found in wet grasslands with common reeds of less than approximately 1 or 2 m in height, and with abundant understory.

Songs of a Yellow-browed Warbler Phylloscopus inornatus were recorded during the breeding season at the tree line boundary in Mount Norikura, central Japan. Yellow-browed Warblers have been known as migrants or rare winter residents in Japan, and this is the second record during the breeding season. They breed in habitats dominated by Japanese Larch Lalix leptolepis, birch Betula sp., and Japanese Stone Pine Pinus pumila. The tree line in Japanese mountains is dominated by Erman's Birch B. ermani, with adjacent Japanese Stone Pine scrubs. Thus, the highland areas of the Japanese mountains are assumed to be suitable potential habitat for Yellow-browed Warblers during the breeding season.

Two juvenile Eurasian Bullfinches Pyrrhula pyrrhula were captured on 20 June 2023, during a constant-effort mist-netting survey conducted in the lowland forest (200 m asl) of southeast Sapporo, Hokkaido, during the breeding season. They had juvenile plumages, before molting to the first winter plumage. As these two birds were captured in the same net at the same time, they seem to be a part of a family or juvenile flock. Several studies have reported that the Eurasian Bullfinch bred in low-elevation sites, especially in the north and east of Hokkaido. On the other hand, in southwestern Hokkaido including Sapporo City, there have been no observations or captured data of juvenile birds at lower than 300 m during the breeding season (from June to August), and there are few reliable breeding records of bullfinch in the area. It is more likely that these juvenile birds fledged from the nest of a breeding pair that accidentally bred in the vicinity of the capture site, rather than fledging in the high-elevation area and moving to the lowland. Whether this possible breeding record of bullfinches in the lowland forest of western Hokkaido is a rare event or will continue to occur in the future needs to be carefully monitored.

We documented the predation of a Brown Rat Rattus norvegicus by a Great Cormorant Phalacrocorax carbo, a large fish-eating bird, by direct observation. There have been few records of predation on mammals by cormorants. We assume this is the first direct observational record of predation on mammals by the Great Cormorant.

Invasive species can have a negative impact on native species due to various factors, such as competition for food resources and habitat, and direct predation. Chinese Hwamei Garrulax canorus is an invasive species whose distribution has expanded rapidly in Japan over the past few decades. However, there are no reports on its impact on native species through predation. We conducted video recordings of artificial open-cup nests and eggs in 2022 at the foot of Mt. Fuji to identify nest predators. We recorded Chinese Hwamei carrying an artificial egg out of the nest. Although we were not able to record the individual attempting to feed on the egg, we cannot rule out the possibility that this species is a direct predator of birds nesting in similar habitats

We used high-definition photography to investigatee fruit-feeding behavior of Eurasian Tree Sparrows Passer montanus. Using a digital video camera equipped with a super-telephoto zoom lens, observations were conducted in the Iwai area of Moroyama, Saitama Prefecture, from mid-January to mid-February 2022. Our study revealed that sparrows use two behavioral types to feed on fruits. The first type is hulling, when sparrows used their beaks to remove the outer coverings of the fruit and then swallowed only the fruit. Sparrows used this method to feed on Asian cultivated rice Oryza sativa, Amur silvergrass Miscanthus sacchariflorus, southern crabgrass Digitaria ciliaris, and Japanese panicgrass Panicum bisulcatum. The second type is chewing, when the sparrows broke down hard pericarp or bracts of the fruits by rotating fruits on the tongue and crushing them between the tongue and upper palate. This chewing type was further categorized into two types based on subsequent observed actions. The first was sorting swallowing, in which sparrows selected and discarded broken hard pericarps and seed coats, or involucres, and swallowed only the remaining edible parts. The sparrows used this method to feed on Japanese hop Humulus japonicus, giant ragweed Ambrosia trifida and cobbler's pegs Bidens pilosa var. pilosa. The second one was non-sorting swallowing, in which the sparrows swallowed all parts of fruits without discarding broken pericarps and seed coats. The sparrows used this method to feed on Japanese panicgrass Panicum bisulcatum and pale smartweed Persicaria lapathifolia. In the case of green amaranth Amaranthus viridis, the sparrows exhibited two actions: they initially removed the pericarp, then chewed and crushed the seed, or they swallowed them intact. In some instances, they discarded a piece of seed coat after chewing.