著者

Hiroyuki NISHIMURA Nobuaki NAKAMUTA Yoshio YAMAMOTO

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.22, no.1, pp.35-44, 2023 (Released:2023-01-26)

参考文献数

54

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In this study we investigated the eye morphology and retinal topography of two owl species in relation to their visual environment. Although Short-eared Owl Asio flammeus is larger and weighs more than Japanese Scops Owl Otus semitorques, its eye dimensions (weight, corneal diameter, and axial length) are all smaller than the scops owl's. Owl retinas were examined in Nissl-stained whole-mount preparations. The total number of retinal ganglion cells (RGCs) was greater in the Japanese Scops Owl (4,703.0×103 cells) than in the Short-eared Owl (2,346.8×103 cells). The eye morphology of, and the number of RGCs in the Japanese Scops Owl indicate that it is more adapted to a nocturnal habit. An area of high-density RGCs was horizontally distributed in the temporal retina of the Short-eared Owl, with a peak density of 17.4×103 cells/mm2. In the Japanese Scops Owl's temporal retina, there was an oval-shaped arrangement with a peak density of 23.1×103 cells/mm2. These distributions indicate that whereas Short-eared Owl is adapted to open habitats, Japanese Scops Owl is adapted to enclosed habitats. The RGCs of both species were classified into three categories (small, medium, and large) based on the size and appearance of somas. In both species, medium-sized cells predominated, and the proportion of large-sized cells was smallest. The distribution and high-density areas differed among these groups, suggesting adaptation to the visual environment. The high-density areas of these groups cover the nasal visual fields, which include the overlap for binocular vision.

著者

石沢 慈鳥

出版者

The Ornithological Society of Japan

雑誌

鳥 (ISSN:00409480)

巻号頁・発行日

vol.16, no.78, pp.409-413, 1961-12-15 (Released:2009-02-26)

被引用文献数

3 1

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Judging by the personal reports received by the author from lighthouse keepers in various parts of Japan, the following may be suggested as possible behaviour of night migrants, particularly the Passrines. 1) The passage of night migrants is noticed offshore rather than ashore where there are islands and capes to avoid, and they fly low close to the seasurface. 2) As generally said, they migrate in clear nights, but when the sky suddenly became overcast or rainy, they may be lost and if a lighthouse were close enough its dim light may attract them. In such cases, some of them die struck at the lighthouse and others spend the night nearby to start again in the next favourable evening. In clear night this never happens. 3) The second case of migrant destruction at lighthouses occurs when the weather was good during the day and became cloudy or rainy towards evening. On such a day, migrants gathering around lihthouse at a cape where there are usually good cover for rest, become restless to start for night flight, but the sudden overcast condition urges them only to fly around the light and some or numbers of them will strike at it. 4) Stronger the light the more migrants are attracted from greater distances and the lighthouse at more unstable weather condition is responsible for more migrant victims. 5) In recent years, however, the birds struck at lighthouses has become extrmely fewer, owing possibly to: a) the genereal decrease of bird numbers and b) increase of coastal village lights and lights of fishing boats on the coastal seasurface.

著者

Masaoki Takagi Kana Akatani

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.10, no.2, pp.151-156, 2011 (Released:2012-04-06)

参考文献数

18

被引用文献数

6

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We identified the diet of owlets of the Daito subspecies of the Ryukyu Scops Owl Otus elegans interpositus on Minami-daito Island during late May and early June 2009, by means of high-resolution color photography. Cockroaches were provided by parents to their young at all eight nests studied, and contributed the largest single component of the diet (33%). Orthoptera species, which inhabited open grassland habitats, constituted >20% of the total occurrences in the diet of owlets. It is suggested that Ryukyu Scops Owls depend heavily on food items obtained from habitats that have been modified by human activity on Minami-daito Island. Diets for owlets differed widely among nests, and the differences were considered to result from individual differences among parents and/or the environments surrounding each nest.

著者

Hong ZHOU Wei LIANG

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.22, no.1, pp.93-96, 2023 (Released:2023-01-26)

参考文献数

22

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On 13 June 2021, a video was recorded showing an adult female Asian Koel Eudynamys scolopaceus removing three Elliot's Laughingthrush Trochalopteron elliotii nestlings from a nest in a thicket on the banks of Liqiu River in Xinduqiao Town, Kangding, Sichuan, Southwestern China. This is the first record of an Asian Koel removing nestlings from a potential host's nest. Of the various brood parasitism hypotheses, this behavior is most consistent with the farming hypothesis, further suggesting that farming behavior may be a common strategy used by obligate brood parasites.

著者

Chun-Chiu PANG Yik-Hei SUNG Yun-Tak CHUNG Hak-King YING Hoi-Ning Helen FONG Yat-Tung YU

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.22, no.1, pp.81-86, 2023 (Released:2023-01-26)

参考文献数

34

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Our study provides the first GPS tracking data of Little Egret Egretta garzetta from an East Asian population. Our two main objectives were to reveal the migratory route and migratory strategy of Little Egret, and to study inter-annual breeding and wintering site fidelity. Our data, from an adult and a juvenile, suggest that this species is a short-distance high-speed migrant using few or no stopover sites. Both individuals displayed high breeding and wintering site fidelity. They also used very small winter home ranges, probably associated with high prey availability in aquaculture ponds.

著者

Canchao YANG Xiangyang CHEN Zhengwang ZHANG Wei LIANG

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.22, no.1, pp.87-92, 2023 (Released:2023-01-26)

参考文献数

23

被引用文献数

2

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We used radio telemetry to provide the first information concerning home range size of Hainan Partridge Arborophila ardens, a vulnerable species endemic to Hainan Island, China, in both a fragmented and a continuous natural rainforest. Both the monthly and daily home range sizes of the population in the fragmented rainforest were significantly larger than those in the continuous rainforest, with no difference between males and females. Fragmentation reduced habitat quality and thus may have forced the partridges to forage over a wider range, which may threaten their survival.

著者

Taichi KATO Chia-Te CHIU Die-Hua TSAI Elena PAVLENKO Marina KOSAREVA Hironobu ITOU Haruka KONO

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.22, no.1, pp.97-104, 2023 (Released:2023-01-26)

参考文献数

29

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We describe, for the first time, the rattling call of the Crested Honey Buzzard Pernis ptilorhynchus. This was previously considered to be a unique vocalization of European Honey Buzzard Pernis apivorus; however, we detected this series of rapidly repeated notes given by an adult female, a second-year, a juvenile and a nestling Crested Honey Buzzard. The rattling calls appeared to be given at times of great excitement, such as to an approaching intruder, mate or parent at the nest, or to a familiar person who usually gave food in the case of captive individuals. The rattling call of an adult female Crested Honey Buzzard at the nest was at a frequency of 2.12 (s.d.±0.07) kHz, and lasted 141 (s.d.±18) ms, which was higher and longer than in European Honey Buzzard.

著者

Kaoru FUJITA Go FUJITA Hiroyoshi HIGUCHI

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.22, no.1, pp.67-79, 2023 (Released:2023-01-26)

参考文献数

74

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Inspired by ecologists R. H. MacArthur and E. O. Wilson, who pioneered the use of islands as ideal model systems for researching the formation and maintenance of biodiversity, we studied two sympatric passerine bird species on a volcanic archipelago, in Japan. We focused on the occupancy and co-occurrence of Varied Tit Sittiparus varius and Cinereous Tit Parus cinereus, both members of the Parus guild, on the Izu Islands. Their populations range from being stable, and co-occurring, to being temporally unstable (with local extinctions, invasions, and species replacement) and even totally absent. Using results from several surveys carried out on the islands over the last 60 years, and our own contemporary surveys, we tested the ecological drivers of inter-island occupancy through occasional dispersal of these two species. We found that both species had positive relationships with island size and vegetation diversity, while Cinereous Tit exhibited a negative associating with distance to the mainland (Honshu, Japan). Cinereous Tit was also negatively correlated with Varied Tit, but their co-occurrence was positively associated with island size, connectivity, and vegetation diversity. We suspect that resource constraints play a significant role in the distributions of the two species on the islands. Varied Tit is dominant over Cinereous Tit, but Cinereous Tit is able to utilize a wider range of habitats and resources. We also discuss the potential for a competition-colonization trade-off for the two species on the islands.

著者

山階 芳麿

出版者

The Ornithological Society of Japan

雑誌

鳥 (ISSN:00409480)

巻号頁・発行日

vol.11, no.51-52, pp.1-46, 1941-10-30 (Released:2008-12-24)

参考文献数

19

著者

Andrey BUSHUEV Ekaterina ZUBKOVA Anvar KERIMOV

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.20, no.2, pp.213-222, 2021 (Released:2021-07-31)

参考文献数

41

被引用文献数

1

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The Scarlet-backed Flowerpecker Dicaeum cruentatum (Dicaeidae, Passeriformes), a sedentary species of Southeast Asia, is among the smallest passerine birds (5–6 g). Despite its very small size, it feeds mainly on plant foods, such as berries, nectar, and green seeds. We found that in conditions of likely food shortage Scarlet-backed Flowerpeckers were able to greatly reduce their metabolic rate at a relatively high ambient temperature (26–28°C). This is within the thermoneutral zone of most tropical birds, although slightly cooler than the normal lower critical temperature of flowerpeckers. In this state, the resting metabolic rate (RMR) of three individual, free-living Scarlet-backed Flowerpeckers from Vietnam averaged 1.57 mL O2/g*h, which was 3.4 times lower than their non-torpid RMR, measured at the same ambient temperature (Ta=~27°C) and 2.5 time lower than their basal metabolic rate (BMR) measured at Ta=~31°C. We did not measure the body temperature (Tb) of these individuals, but the dramatically low oxygen consumption provides evidence of torpor, an energy-saving physiological state, which is very rare among passerine birds. The skin Tb of active flowerpeckers, just before nocturnal RMR measurements, averaged 41.1°C (their cloacal Tb was 41.2°C), while in resting non-torpid birds at night the skin Tb averaged 36.3°C. Our report is the first quantitative evidence of torpor in the family Dicaeidae.

著者

中村 浩志

出版者

The Ornithological Society of Japan

雑誌

日本鳥学会誌 (ISSN:0913400X)

巻号頁・発行日

vol.39, no.1, pp.1-18, 1990-08-25 (Released:2007-09-28)

参考文献数

40

被引用文献数

44 45

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文献調査および野外調査により,日本でカッコウに托卵された記録のある宿主,本州中部におけるカッコウの托卵率,および新しい宿主オナガとの托卵関係成立過程についての調査を行った.1)日本ではこれまでにカッコウの宿主は計28種記録されている.宿主の数は,本州中部が20種と最も多かった.2)本州中部の長野県では,主要宿主6種の托卵率はいずれも10%以上であった.最も高い托卵率は,新しい宿主オナガの79.6%であった.3)カッコウ宿主との托卵関係は,過去60年間に大きな変化がみられた.本州中部ではカッコウは約15年前からオナガに托卵を開始したが,托卵率は急速に高まり,現在ではオナガの繁殖分布域のほぼ全域にカッコウの托卵が広がった.逆に,今から60年前の主要宿主であったホオジロは,現在ではまれな宿主に変った.4)新しい宿主オナガへのカッコウの托卵は,最近両者が分布を拡大し,分布が重った結果開始された.カッコウの托卵は,分布が重なってすぐに開始されたのではなく,多くの地域では本格的に開始されるまでには10年から15年かかっていた.5)長野県におけるカッコウの托卵にみられる特徴と新しい宿主オナガとの托卵関係成立過程についての論議を行った.

著者

Eugenia V. BRAGINA Irina V. BALAN Nadezhda V. KUZNETSOVA Mikhail P. PARILOV Jonathan C. SLAGHT

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.21, no.1, pp.53-62, 2022 (Released:2022-01-31)

参考文献数

30

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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.

著者

Wieland HEIM Aleksey ANTONOV Ilka BEERMANN Simeon LISOVSKI Martha Maria SANDER Steffen HAHN

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.21, no.1, pp.121-126, 2022 (Released:2022-01-31)

参考文献数

45

被引用文献数

6

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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.

著者

Masaharu HAYAKAWA Mieko SUZUKI-MATSUBARA Kazumi MATSUBARA Satoshi KANAZAWA Takashi FUJII Wataru KITAMURA Ryoh Alexander MUROFUSHI Akihiko MORIYAMA

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.21, no.2, pp.155-163, 2022 (Released:2022-08-13)

参考文献数

21

被引用文献数

1

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Little Tern Sternula albifrons sinensis was been categorized as Endangered Class II by the 2020 Ministry of the Environment's Red List in Japan. For an effective conservation program for the taxon, the unit of conservation needs to be understood. In this study, we investigated genetic and morphological diversity as a clue to clarify the units to be protected. Blood samples were collected from 47 individuals in four different breeding sites in Japan (Tokyo, Chiba, Fukuoka, Okinawa). The nucleotide sequences of the control region of mitochondrial DNA were used to analyze their genetic diversity and structure. Basic morphological features were also compared. Nucleic acid base substitution, deletion, or insertion were identified at 30 sites of the 1029-bp sequence alignment of the control region, leading to identification of 30 different haplotypes. Genetic diversity was high in the four breeding populations, and haplotype frequencies showed no indication that specific genotypes were present at extreme frequencies. This suggests that the population of Little Tern nesting in Japan has been maintained without recent bottleneck events. The haplotype network formed two major haplotype groups from the 30 haplotypes. Haplotypes of one group were abundant in the Tokyo, Chiba, and Fukuoka populations. In contrast, those of the other group were frequent in the Okinawa population. Pairwise haplotype analysis between populations also revealed that the genetic variations at Okinawa differ from those of the remaining three populations. Furthermore, the Okinawa population showed different morphological characteristics compared to the Tokyo/Chiba populations. These results collectively suggest that the population of Little Terns in Japan is divided into at least two different populations.

著者

Shota DEGUCHI Yousuke UEDA Masumi HISANO

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.21, no.2, pp.133-143, 2022 (Released:2022-08-13)

参考文献数

60

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Many bird species with heterogeneous distribution are at risk of extinction. It is essential to identify and elucidate environmental factors explaining such distribution patterns to develop effective conservation strategies for those species. Yellow Bunting Emberiza sulphurata is an endangered migrant bird species exhibiting heterogeneous breeding distribution in Japan. Here we clarify the spatial distribution and the altitudinal range of the Yellow Bunting breeding range, and detect environmental factors (e.g., climate and topography) influencing their distribution pattern using an extensive dataset from the national breeding birds survey of Japan. The presence of Yellow Bunting during the breeding season (1997–2002) and six environmental factors (temperature, snow depth, elevation, tertiary layer, landslide area and forest edge density) were analyzed using maximum entropy models (MaxEnt). We found that Yellow Buntings were present in a higher proportion of survey grids in northern Honshu (the main island of Japan) than elsewhere in the country, and they mainly occurred in areas below 700 m above sea level. Moreover, the elevation of the occupied grids decreased with latitude. Temperature and snow depth were of greater importance (0.380 and 0.350, respectively) than other factors in explaining the breeding distribution of the Yellow Bunting. Our study highlighted the location of the core areas of the Yellow Bunting's breeding distribution, and demonstrated that lower temperature and deeper snow cover are the critical determinants of those areas. There may be abundant prey and fewer avian competitors, such as resident bird species, in colder regions, and more frequent snow avalanches and water from melting snow may establish the marshy and bushy habitat preferred by Yellow Buntings. These findings are essential for developing effective conservation strategies for the endangered Yellow Bunting. As past mass-trapping may have also influenced the heterogeneous distribution of the Yellow Bunting, this is an important avenue for future research from a different perspective.

著者

Ming-Tang SHIAO Mu-Chun YAO Mei-Chen CHUANG

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.21, no.2, pp.165-176, 2022 (Released:2022-08-13)

参考文献数

54

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In heterogeneous landscapes, birds may mistime their breeding attempts relative to local food abundance. How birds cope with this challenge has been little studied. In this study, we compared the provisioning behavior and nestling condition of the Green-backed Tit Parus monticolus nesting in a landscape mosaic comprised of native mixed-oak forests and exotic Japanese Cedar Cryptomeria japonica plantations. Parent birds in the larvae-poor plantations time their breeding as they do in the larvae-rich forests and have clutches of similar size. We found that parent birds were flexible in adjusting their criteria for prey choice on the basis of larval abundance. In early spring, in cedar plantations where larval abundance was low, male parents maintained constant nearby feeding trips to the early broods, just as they did in the mixed-oak forests, but reduced their dietary specialization on larvae, while female birds increased their provisioning frequency. Combining both parents' efforts, the early brood nestlings raised in the cedar plantations received food deliveries more frequently and with a higher proportion of non-larval prey than their counterparts did in the mixed-oak forests. In contrast, during late brood rearing, when larvae were abundant, both parents in the plantations foraged heavily on larvae at the expense of other prey, just as they did in the mixed-oak forests. We found that parent birds reared heavier nestlings as the contribution of large larvae to the diet increased. Moreover, the nestlings during early broods in the plantations had lower body weights than their counterparts in the mixed-oak forests. We suggest that the provisioning flexibility of Green-backed Tits helps them gather food for raising nestlings when their breeding attempts are less synchronized with the larval food supply in their habitat. As a result, they can breed successfully in the exotic cedar plantations.

著者

Yuji OKAHISA Yoshinori KANEKO Hisashi NAGATA Kiyoaki OZAKI

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.21, no.2, pp.145-154, 2022 (Released:2022-08-13)

参考文献数

48

被引用文献数

1

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An increasing number of reintroduction programs have been set up in recent years in an attempt to reintroduce once extinct species to their indigenous ranges and create self-sustaining populations. However, the released individuals often experience low mating success and fecundity. Appropriate rearing in captivity is considered essential for the successful post-release reproduction of captive-reared individuals. Low post-release mating success and fecundity are also issues in reintroduced Crested Ibis Nipponia nippon populations on Sado Island. These phenomena may be caused by the effects of hand-rearing in captivity, yet temporary hand-rearing is necessary when captive breeding, because rescuing embryos from mortality is essential due to the abnormal behavior of parent birds in captivity. Therefore, the establishment of rearing methods that temporarily protect embryos or chicks while limiting the negative effects of hand-rearing on breeding after release is needed. To overcome these challenges, we tested how captive rearing methods impact post-release courtship behavior, mating success, and fecundity of the ibis. By combining detailed rearing history in captivity with long-term post-release monitoring, we demonstrate that the initiation of parental rearing before the chicks' eyes open is the critical factor leading to increased pseudocopulation frequency and mating success in captive-born male ibis. Based on these results, not hand-rearing the chicks beyond the day after hatching would reduce the impact of hand-rearing on reproduction after release. Rearing methods that take into account the nestling period should be implemented to enhance the efficiency and reduce the cost of avian reintroduction projects.

著者

Hanaka ISHII Masanori YAMAJI Haruki NATSUKAWA Tomohiro ICHINOSE

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.21, no.2, pp.227-234, 2022 (Released:2022-08-13)

参考文献数

39

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The Daurian Redstart Phoenicurus auroreus has expanded its breeding distribution in recent years and now breeds in Japan, previously only part of its wintering range. We analyzed the breeding habitat selection of the population at the nest and territory scale in the Kirigamine Highlands, Nagano, Central Japan. At the nesting scale, the birds chose buildings frequently occupied by humans, while at the territory scale, they avoided sites in larger built-up areas. Our findings demonstrate that the breeding habitat selection of Daurian Redstart is influenced by environmental factors at both nest and territory scales.

著者

Katsumi TAMADA

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.21, no.2, pp.215-225, 2022 (Released:2022-08-13)

参考文献数

41

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Rural areas provide various habitats for birds, and some studies have revealed habitat associations in rural bird communities in Japan. Previous studies have primarily focused on waterbirds or the habitat values of abandoned farmland, thus little is known about the importance of cultivated land for rural bird communities. Therefore, in this study, I clarified the characteristics of the avifauna in a rural area of the Ishikari Plain in Shinshinotsu Village, Western Hokkaido, and examined habitat utilization of cultivated land by eight major grassland species; Bull-headed Shrike Lanius bucephalus, Eurasian Skylark Alauda arvensis, Black-browed Reed Warbler Acrocephalus bistrigiceps, Siberian Rubythroat Calliope calliope, Stejneger's Stonechat Saxicola stejnegeri, Chestnut-eared Bunting Emberiza fucata, Black-faced Bunting E. spodocephala, and Common Reed Bunting E. schoeniclus. I conducted bird surveys along three 2-km line-transect routes among rice fields with some wheat, non-wheat crop fields, and weedy areas from April to October from 2016 to 2018. I recorded a total of 51 species of three general types: grassland birds, residential birds, and water birds. Rice fields in this study areas were flooded during early to mid-May to mid to late August, however species-specific habitat utilization analyses revealed that a small number of Eurasian Skylark, Stejneger's Stonechat, and Chestnut-eared Bunting inhabited the rice fields during study periods other than the flooding season. A relatively large number of Eurasian Skylark was observed in wheat fields and non-wheat crop fields throughout the study period, and Stejneger's Stonechat and Chestnut-eared Bunting were temporarily observed in those habitats. The other five species only rarely observed in rice, wheat, or non-wheat crop fields, but all eight species were observed in weedy areas. The characteristics of the avifauna in this rural area of Western Hokkaido proved to be quite different from previous studies conducted in the Kanto Region of Honshu. For the conservation of biodiversity and birds in rural areas, it is necessary to investigate the avifaunal characteristics of various regions of Japan.

著者

Golusu Babu RAO Santhanakrishnan BABU Goldin QUADROS

出版者

The Ornithological Society of Japan

雑誌

ORNITHOLOGICAL SCIENCE (ISSN:13470558)

巻号頁・発行日

vol.21, no.2, pp.199-213, 2022 (Released:2022-08-13)

参考文献数

75

被引用文献数

5

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The Indian coast and its adjacent wetlands host large congregations of shorebirds, including winter and passage migrants of high conservation priority, along the Central Asian Flyway. Identifying crucial wintering and stopover sites and seasons is an important step toward conserving shorebirds and their habitats along the Indian coast. We assessed spatial and temporal patterns of shorebird composition from January 2015 to December 2016 at seven estuaries along Maharashtra's Sindhudurg district, which is located on India's west coast, a coastal zone of international importance for shorebirds. Three potential shorebird habitats –mangroves, mudflats, and sandy beaches – were selected at each of the estuaries chosen for the study. We established three vantage points, one each in the mangrove, mudflat, and sandy beach areas, to count birds during low tide. The total count method was followed to count birds, and occasional photograph-based counts were also made when flock size was big or the flocks kept changing. We recorded 31 species of migratory shorebirds, of which 68% wintered and 32% used the Sindhudurg coast as migratory stopover site. We found significantly high richness and abundance of shorebirds during winter and in the mudflats. nMDS was used to determine species composition of shorebird across habitats and months and revealed distinct patterns of composition in five unique phases: arrival, wintering, early departure, departure, and breeding. Our results revealed that the species composition of shorebirds is not homogenous across sites and months, and is largely driven by the habitat heterogeneity of estuaries, seasonality, and anthropogenic disturbances. These results provide baseline information on shorebirds along a stretch of India's west coast and highlight the importance of mudflats and non-protected coastal wetlands for shorebirds.