Cuckoos Cuculus spp. have a large home range in the breeding season. It is difficult to obtain detailed information about their social behavior and the size of their home range through direct observation due to their concealed activity in the forest. Accordingly, we lack such information about many cuckoo species, with the exception of the Common Cuckoo Cuculus canorus. This research represents the first comprehensive investigation of the Lesser Cuckoo Cuculus poliocephalus, using radio tracking. In this paper, we primarily describe the characteristics of the home range and social behavior of the Lesser Cuckoo. Males were observed to actively fly over a wider range (238 ± 74SD ha, Range 138 – 311 ha, n = 5) compared to females. There was no territoriality evident in mating or feeding ranges among all individual males. Conversely, the home range size of individual females varied greatly (188± 216SD ha, Range 37 – 436 ha, n = 3). Aggressive encounters among females were often observed, indicating that females exhibit territoriality, and the sex differences in the home range and territorial spacing pattern observed in this study are likely caused by sex differences in intrasexual conflict.

The contribution of biodiversity to ecosystem stability and productivity has been reported in experiments and surveys on grasslands, forest vegetation, and coastal areas. However, to date, no long-term studies have been conducted from this perspective on the role of birds as predators of forest folivorous insects. Therefore, changes in breeding bird density and in frass production of insect larvae were surveyed for 10 – 20 years in three different forests, including zones with nest boxes and without nest boxes. As the first report of this study, we describe the effect bird predation in controlling the larval damage by birds. The production of folivorous larval frass (g/m²) during May – July was estimated to decrease by an average of 70% due to bird predation. The coefficient of variation (CV) of observed larval frass amount (OFA) in the larch Larix kaempferi forest was significantly smaller in the nest box set forest than in the no-nest box forest. The CV of OFA decreased in forests with higher predatory potential (TPP) of bird communities per OFA. Predation-induced reduction in frass per TPP obtained from the regression model showed a density-dependent functional response. In conclusion, forest insectivorous birds are thought to always play a major role in the frass reduction and stabilization of folivorous larvae damage. To increase the control effect of insectivorous birds, it is necessary to increase the density and diversity of the bird community by introducing broad-leaved trees or holed trees inside and outside the plantations. The effect of predation of larvae by birds on the growth of larch forest will be reported separately.

The Rose-ringed Parakeet Psittacula krameri has expanded its distribution worldwide. Wild populations have been observed in the Japanese Archipelago since the late 1960s, and there are concerns about their potential impacts on ecosystems and conflicts with humans. However, their behavior and habits in urban environments are still not well understood. We counted the number of individuals at four known roosting sites from July 2015 to January 2016. The numbers fluctuated greatly at all roosting sites. Human activities and seasonal changes in the environment likely caused these changes. The roosting site formed on Tilia maximowicziana was abandoned following leaf fall, whereas the use of Ginkgo biloba was continued after leaf fall. The population density increased as the roosting number of individuals increased because the physical size of the roost remained unchanged, which may result in problems with noise and bird feces to humans.

To explore the possibility of counting waterfowls on the water using satellite imagery, we first examined Pléiades (0.5 m resolution) images. In eleven requested images of the Utonai Lake in the winter of 2022/2023, we found white spots in the four images. The locations and the numbers of these white spots corresponded with swans on the water as recorded in land-based camera pictures shot at the same time. However, swans and ducks on the ice were not evident in these Pléiades images. The numbers of swans on the waters of lakes/rivers counted by the land-based waterfowl population census in the winter of 2012 – 2022 appeared to be similar to those of white spots in the images taken within 5-days for nine cases, but not for one. A feeding group of ca. 10 gulls formed at sea was also not detected by the satellite. This study shows that the individual swans on a calm lake water can be detected using Pléiades images.

Birds serve important ecological roles in urban greenspaces, and understanding the relationship between greenspaces and bird populations is important for conserving urban biodiversity. As many as 100 bird species have been recorded in large urban forests such as those at the Institute for Nature Study and Meiji-jingu Shrine in Tokyo, Japan. The Tamagawa- josui Canal in western Tokyo was established during the Edo period (1653) to supply water, but today it functions as an extended green belt and an important nature reserve. The city of Kodaira is situated along the middle of the canal where the green belt is wider, making it especially suitable for birds. We carried out more than 150 line-transect censuses (each 1.2 km long) of this area every year for 10 years, for a total of 2,069 censuses. In total, these censuses recorded 140,057 individuals from 84 bird species, similar to the numbers found in the Imperial Palace woods and greater than those found in other small woods throughout Tokyo. The avifauna composition (number of species) at Kodaira was more biased towards the forest type and less biased towards the wetland type than at other places. The bird population composition (number of birds) was more biased towards the forest-cropland type and less biased towards the generalist type. The monthly mean number of birds observed decreased in summer, likely because some abundant generalist species, such as the Brown-eared Bulbul (Hypsipetes amaurotis) and Jungle Crow (Corvus macrorhynchos), leave the area during summer. Our results underline the importance of conserving the Tamagawa-josui canal for the preservation of biodiversity in Tokyo.

This survey investigated the breeding range of the Kamchatka Leaf Warbler Phylloscopus examinandus in Hokkaido, Japan, using line censuses and trapping surveys during the breeding season from July to August. The results confirmed the presence of 35 breeding males that were probably breeding around Mt. Shiretokodake in the Shiretoko mountains, and Mt. Sharidake on the Shiretoko Peninsula. However, on Mt. Petegari, Mt. Memurodake, and Mt. Pankenushidake in the Hidaka Mountains the distribution of the warblers could not be confirmed. In addition, 29 individuals were released as markers or collected as specimens during the trapping survey. These results suggest that the Kamchatka Leaf Warbler breeds only on Shiretoko Peninsula and its surrounding areas in Hokkaido. This is the first report of the capture of Kamchatka Leaf Warblers during the breeding season in Hokkaido.

In August 1932, a juvenile penguin was brought to Ueno Zoological Gardens from Chile. Following its first molt in January 1933, it was identified as a Magellanic Penguin Spheniscus magellanicus. This penguin was kept at the zoo for about five and a half years, and housed for a short time with a Humboldt Penguin S. humboldti or waterfowl. This penguin was already very familiar with people when it arrived in Japan, so it was taken out of its

enclosure and participated in various events such as animal photo sessions. Photographs and news of these events were frequently published in newspapers and photography magazines. It is believed that this Magellanic penguin greatly contributed to increasing the popularity of penguins by interacting closely with many people.

An unusual flycatcher with a black lower mandible was found dead in Chiba Prefecture, Japan. DNA barcoding identified the specimen as a Red-breasted Flycatcher Ficedula parva. We observed and examined the external morphology of this specimen in detail, which was impossible when the individual was alive.

Niigata Prefectural Bird Conservation Center raised two white morphs of the Carrion Crow Corvus corone. They survived for 29 years and 7 months, and 16 years and 5 months, respectively. We here report on their captive conditions.

Japanese names are a useful tool for Japanese speakers to communicate scientifically about birds. However, nearly 40 years have already passed since the most influential book treating Japanese names for all modern birds (Yamashina 1986) was published. During that time, the classification of birds has undergone major changes. Here we provide a revised list of Japanese names for genera and species of nightjars and allied birds (Caprimulgiformes, Steatornithiformes, Nyctibiiformes, Podargiformes and Aegotheliformes), which adopts the latest classification system (Gill et al. 2024).