Understanding the behavioural responses of bird species to their environments is important for effective conservation, especially in captive-management and resource-provisioning programs. Camera traps present a growing opportunity to research bird breeding and foraging behaviour in situ. Remotely triggered cameras are commonly deployed to study mammals and large terrestrial birds. They are rarely used to survey small or arboreal birds due to habitat constraints. However, a wealth of information about small or arboreal birds can be generated opportunistically from camera traps in the course of collecting data on other taxa. Here, we describe and quantify the types of behavioural information that can be so gleaned, based on over 1,700 small-bird images captured as “collateral” during a geographically extensive mammal-focused camera study in Tasmania, Australia in 2018–2020. Postural analysis of images revealed 10 distinct behaviours. Large- and medium-sized terrestrial bird species were most commonly observed (61.6% of behavioural images), but small and arboreal species were also photographed at high rates (18.4% and 29.5% of behavioural images respectively). Investigative activity was the most commonly observed behaviour in small and arboreal species (around half of all images), but feeding, mating and even very rare behaviours like fur plucking, were also captured photographically. This case study reveals the value of opportunistically analysing camera trap images for small or arboreal birds species, especially when they are of conservation interest, even for cases where deliberately targeting them would not be a cost-effective strategy.

To explore the environmental adaptation strategies of high-altitude breeding birds to alpine regions, we studied the breeding ecology of the Snow Partridge (Lerwa lerwa) in the Qinghai-Tibet Plateau. Incubation behavior was determined using data loggers in Basu County (2018) and Cuona County (2019), in the Tibet Autonomous Region, China. We monitored seven Snow Partridge nests; clutch sizes ranged from 4–5 eggs per nest (mean=4.71±0.45 eggs, N=7), egg mass ranged from 28.1–37.7 g (mean=31.1±2.5 g, N=28), and the hatching success rate was 87.9% (N=33 eggs, six nests hatched successfully, and one nest suffered a predator attack). Nesting females typically took 1–4 recesses each day (mean=1.8±0.7, N=39 days). In five females, the first daily recess occurred at 0601 to 0709 (mean=0626±16 min, N=39 days) and the duration ranged from 60 min to 615 min (mean=179±102 min, N=39 days). The average nest attendance was 85.6±5.9% (75.9–92.8%, N=6 nests). Compared with other Galliformes, Snow Partridges lay larger eggs and smaller clutches, leave their nests fewer times per day but with a lower nest attendance, and a bimodal pattern of recess timing. Additionally, Snow Partridges build cave nest structures. These characteristics are highly adapted to the alpine region of the Tibetan Plateau and balance the thermal needs of the developing embryos and the self-maintenance needs of the incubating females.

Nest-site selection can have important fitness consequences for birds. Understanding what information individuals use to choose nest sites is therefore crucial not only for understanding the dynamics of populations, but also for the conservation of species. We identified habitat characteristics predicting nest site selection in the threatened Jankowski's Bunting Emberiza jankowskii in Mongolian grasslands. We recorded 14 habitat characteristics around 83 nests of Jankowski's Bunting and at 83 random points at local and landscape scales. Compared with the random points, Jankowski's Bunting nest sites had significantly greater values for plant canopy, grass height and grass density at the local scale, while such significant differences were not found in the percentages of natural grassland or bare cropland at the landscape scale. The generalized linear model performed on selected independent variables confirmed that Jankowski's Bunting nests occurred more often in densely vegetated areas with tall grass and scrubs. This study highlighted the importance of plant cover and vegetation height in the species' nest site selection and suggested that continuous control of grazing pressure is necessary to better conserve the natural grasslands needed for the persistence of Jankowski's Bunting.

Parental role division is common among monogamous birds. Among raptors, males typically expend more effort to feed their chicks than do females, yet few studies have focused on how each pair establishes this role division. Therefore, in this study we examined the mechanism of role division in the Ryukyu Scops Owls Otus elegans on Minami-daito Island. Pairs of this species typically remain together and use the same nest over several years, so there is a possibility that their role division improves with experience over time. To clarify this, we studied the feeding frequency and territorial usage of individuals. Males fed their chicks more frequently than females, and experienced individuals using the same nests fed their chicks more than inexperienced individuals. On comparing experienced and inexperienced pairs, we found that experienced individuals hunted closer to the nest than inexperienced individuals. Furthermore, the home ranges of the males and females of experienced pairs, overlapped less than those of inexperienced pairs. Experience of using a nest site in consecutive years may allow such individual behavioural differences to develop and be involved in role division in parental care.

Avian brood parasitism is a reproductive strategy in which a parasitic species lays its eggs in the nests of a host. In response to parasitism, hosts have evolved various defence strategies. One of the host defences against intraspecific and interspecific brood parasitism is to distinguish parasitic eggs based on intraclutch variation in egg appearance. Hosts can improve their ability to discriminate parasitic eggs by lowering the degree of their intraclutch variation in egg appearance. Therefore, intraclutch variation may affect the egg rejection behaviour of hosts. In this study, we conducted experiments to study egg recognition and rejection behavior for mimetic eggs in Azure-winged Magpies Cyanopica cyanus in Korea. We also investigated the level of variation in egg appearance (egg color, spottiness and volume) in order to explore whether the degree of this variation is associated with the rejection decision. We found that there were no differences in egg coloration or spottiness between the rejecter and accepter. However, we found that intraclutch egg volume variation in rejecters was significantly lower than that in accepters, indicating that the Azure-winged Magpie is likely to recognize its own eggs by lowering its intraclutch variation in egg volume as a defensive strategy against brood parasitism. This study suggests that the Azure-winged Magpie use not the differences in egg coloration but egg volume to discriminate and reject closely mimetic conspecific eggs.

Red-crowned Grus japonensis (IUCN status: Endangered) and White-naped Antigone vipio (IUCN status: Vulnerable) cranes are both rare, with wild populations of ∼3,000 and ∼6,000 individuals, respectively. Since 1991, the Rare Bird Reintroduction Station at the Khingansky State Nature Reserve, Russia, has been rearing and reintroducing chicks of both species to bolster wild populations. The station uses two different chick-rearing methods: (1) the “parent-reared” method, in which chicks are raised in enclosures by natural parents and stay with them until their release into the wild, and (2) the “semi-wild” method, a modification of hand-rearing, in which cohorts of 2–7 chicks spend most of their time together in an enclosure but are guided on daily excursions outside the enclosure, under supervision of a keeper from a distance of 30–50 m. We have assessed and compared apparent survival of crane chicks reared under these methods. Of the 165 juveniles released into the wild from 1991–2019 (104 Red-crowned; 61 White-naped), no difference was found between apparent survival of parent-reared and semi-wild chicks. Six-month apparent survival of Red-crowned Cranes was 84.2% (95% confidence interval: 75.3–90.3%); for White-naped Cranes –89.5% (95% CI: 83.9–93.3%). Both parent-reared and semi-wild chicks were later observed in mated pairs with their own offspring (17 chicks in total), coupling with either other reintroduced birds or with wild individuals. We conclude that both the parent-reared and semi-wild methods had similar outcomes with respect to apparent survival. However, since the semi-wild method is less costly with respect to time (i.e., more juveniles can be released annually using this method) we recommend that it be used whenever possible to bolster these Endangered and Vulnerable populations.

Raptors are long-lived apex predators with a lower rate of breeding success than smaller birds. Therefore, their responses to the construction of wind farms must be documented to assess the impact of wind energy on birds. We estimated the home ranges of three pairs of Mountain Hawk-Eagle Nisaetus nipalensis orientalis before, during, and after construction of a wind energy facility to assess changes in home range. We also compared altitude, inclination, and land cover composition of habitats within home ranges during the construction phase. For one pair, the home range of which included wind farm construction, the distance from the home range to the construction area during the first year of construction increased significantly compared with that during pre-construction, but there was no significant difference between the post-construction and construction phase. It is thought that the construction of a wind farm within the home range caused the displacement, and that displacement began during the first phase of construction and continuing during the second phase and afterwards. Because the birds moved about 500 m away from the wind farm during the construction and post-construction phases but succeeded in breeding, we think that the distance of 500 m may be meaningful in terms of mitigating disturbance. The nest trees of all three successful breeding pairs were more than 1.3 km from the closest wind turbine, perhaps indicative that impact on breeding is light if construction takes place this far away from breeding sites. No significant differences in either land cover or inclination within home ranges were found during the construction phase, which might explain why all birds bred successfully during the second construction phase. After construction, all three pairs continued to use areas with similar habitat.

Research on the breeding ecology of birds is key to understanding not only their ecological, evolutionary and behavioral traits but also for developing effective conservation strategies. We studied the breeding ecology of Oriental Skylark Alauda gulgula on farmland in the Mardan District, Khyber Pakhtunkhwa Pakistan from April to July 2018. Nests were searched systematically in all potential farmland sites. A total of 39 nests was found, of which 25 were active. Nests were cup shaped or somewhat oblong mainly concealed within 15–25-cm tall grasses. Nests were constructed of local grasses and dry leaves of trees and local crops. The average nest mass was 17.20±0.9 g. Average nest measurements were: outer diameter 9.17±0.8 cm, inner diameter 7.65±0.6 cm and inner cup depth 6.45±0.5 cm. Eggs were oval in shape and dusty-grey in colour with dark grayish spots more concentrated on the broader end. The average egg mass was 3.0±0.13 g. Average egg measurements were: width 2.30±0.4 cm, egg length 3.25±0.17 cm² and egg volume 3.68±0.07 cm³. The average incubation lasted 12.08±0.7 days and the nestling period was 12.59±0.5 days. The average clutch size was 3.16±0.9 eggs, and brood size averaged 2.76±0.7 nestlings. Fledgings were found from early May to late July. The average number of young fledged was 2.18±0.7 and overall breeding success was 60.75%. Results suggest that farmland represents a good yet risky breeding habitat for the skylarks. Factors such as nest destruction, grazing, predation, agricultural disturbance and human intervention are affecting the breeding success of Oriental Skylark in Pakistan.

Alcidae (auks) is a family of wing-propelled diving Charadriiformes, which includes 24 extant species distributed in the Holarctic region. Here, we describe a fossil humerus of Pliocene Alcidae (approximately 4.5–3.5 Ma) from the Fukagawa Group in Hokkaido, Japan. Although this specimen is incomplete and the diagnostic characters of the specific genus are lacking, it shares similar characteristics with Uria, such as the size, dorsoventrally compressed humeral shaft, low and smooth crista deltopectoralis, and a nearly rectangular supracoracoideus scar. While several Alcidae fossils have been reported from the Miocene–Pleistocene deposits (23.0–0.0117 Ma) of the Eastern Pacific (i.e., Mexico and California, USA), little is known about fossils from the Western Pacific (i.e., Asia), most of which have been found from Pleistocene deposits (approximately 0.7–0.12 Ma). This study, reporting the first Pliocene Alcidae from the Western Pacific, implies that the Alcidae were already distributed in the Holarctic region during the early Pliocene.

Perennial farmlands such as fruit orchards and vineyards often substitute for natural habitats and provide nesting and foraging habitats for birds. Bird use of perennial farmlands has been investigated mainly in Europe and North America, but far less in Asia, which hosts one-third of identified biodiversity hotspots. We aimed to fill this knowledge gap by performing a systematic review of bird studies in fruit orchards and vineyards in Japan. We screened literature written in English or Japanese including both published and non-peer-reviewed (grey material, e.g., books, abstracts of annual meetings, blogs, and unpublished surveys). The review identified 31 bird species, including four Red List species, that nest in orchards and vineyards in Japan. Several studies have provided insights into the habitat quality of fruit orchards, which appears to vary among bird species. Other studies have reported: (1) the effects of orchard management on bird diversity (e.g., positive effects of organic farming and grass cover on bird richness and abundance); and (2) the ecosystem services by birds (e.g., reduction of pest rodents by predatory Ural Owls Strix uralensis). Our review demonstrates the potential importance of fruit orchards and vineyards to bird species that have adapted to human-modified landscapes, although more quantitative studies are needed to investigate the actual breeding performance of birds. We also illustrate the importance of non-English-language literature, including grey literature, to mitigate ecological knowledge gaps in countries where English is not the first language.

Pallas's Reed Bunting Emberiza pallasi was confirmed to be breeding in grassland at the Volchinka River mouth, Northern Sakhalin, Russia, in July 2019. The density of the species was 0.17 territories/ha. The observed individuals were identified as either E. p. polaris or E. p. pallasi based on their morphological characteristics and geographical location. Two nests and two fledglings were discovered. This is the first evidence of this species breeding on Sakhalin Island. Since northern Sakhalin is several hundred to a thousand kilometres away from the previous known breeding range, our study suggests a possible range expansion of this species.

East Asian songbirds are known to migrate along two major corridors: from mainland Eurasia via China to South-East Asia, and from Japan and easternmost Russia through chains of islands in the Pacific to Indonesia and the Philippines. We successfully tracked the hitherto unknown migration of a Blue-and-white Flycatcher Cyanoptila cyanomelana breeding in the Russian Far East. The bird spent five months on Mindoro Island in the Philippines during the non-breeding season and migrated through Taiwan, the Chinese east coast, and the Korean peninsula. Thus, we provide the first direct evidence for songbird migration from mainland Russia to the Philippines.