Brown-eared Bulbul Hypsipetes Amaurotis Research Articles

Further evidence for endozoochory in a mycoheterotrophic orchid Cyrtosia septentrionalis: seed dispersal by the masked palm civet Paguma larvata.

Cyrtosia septentrionalis, an orchid species, is notable for its sausage-shaped red fleshy fruits, which can reach up to 10 cm in length. Previous research identified frugivorous and omnivorous birds, especially the brown-eared bulbul Hypsipetes amaurotis (Pycnonotidae, Passeriformes), as key seed dispersers of C. septentrionalis in natural habitats. This finding challenges conventional belief that orchid seeds are primarily wind-dispersed. Moreover, given the rarity of specialized co-evolutionary relationships between fruits and frugivores, C. septentrionalis may also rely on mammals for seed dispersal in certain regions. We aimed to explore the fruit consumption habits of animals other than birds. Motion sensor-equipped cameras were used to observe interactions with the fruits of C. septentrionalis and assess the viability of seeds post-consumption. The observations revealed three animal species consuming the fruits, with the masked palm civet Paguma larvata (Viverridae, Carnivora) identified as a dominant consumer in the investigated population. Microscopy analysis of seeds retrieved from P. larvata faeces indicated that the seeds remained intact and viable after passing through the digestive system of this carnivorous mammal. The above discovery suggests a potential role for carnivorous mammals in seed dispersal of C. septentrionalis, alongside birds, thus broadening our understanding of the complex seed dispersal strategies employed by orchids.

Nectar microbes may indirectly change fruit consumption by seed-dispersing birds

An increasing number of recent studies show that nectar-inhabiting microorganisms influence plant fitness by mediating interactions between plants and pollinators. However, whether the effects of nectar microbes extend beyond pollination to affect subsequent stages of plant reproduction remains largely unknown. This study aims to explore whether nectar microbes can indirectly affect fruit consumption by birds, which can be essential for seed dispersal and germination. Wild flowers of Eurya japonica trees were experimentally inoculated with the nectar-inhabiting yeast Metschnikowia reukaufii and the nectar-inhabiting bacterium Acinetobacter boissieri, both of which had been previously isolated frequently from E. japonica flowers. In this experiment, I examined whether these microbes changed female reproductive success of the understory tree. Experimental inoculation of flowers with yeasts decreased fruit and seed set compared to those inoculated with bacteria, and the control. Furthermore, fruits with higher seed set tended to be larger, and larger fruits were more likely to be consumed by seed-dispersing birds, including the Japanese white-eye Zosterops japonica, the brown-eared bulbul Hypsipetes amaurotis, and the Daurian redstart Phoenicurus auroreus. These results suggest that nectar-inhabiting microorganisms have the potential to affect plant reproduction by influencing not only plant-pollinator interactions, but also by indirectly modifying plant-frugivore interactions via changes in plant-pollinator interactions.

関東地方における秋期のヒヨドリの渡り‐齋藤（１９３５‐１９４３）の観察記録の解析

In the plains of Kanto district, Japan, flocks of the Brown-eared Bulbul Hypsipetes amaurotis often undertake a southern autumn migration. From 1934 to 1942 Mr. Genzaburo Saito made daily observations throughout the annual autumn migrations at Chiba City, Chiba Prefecture, and recorded values of several migration parameters. I analyzed his data to clarify the migration status c. 70 years ago and to assess whether the status differed from the present one. Results showed the annual number of migrating individuals to vary from c. 400 to c. 1,700 with a median of c. 900 and c. 14 individuals in a flock. Flights began in late September and finished in early November, with most flocks flying in October. Comparison with the data of Yamaguchi (2004, 2005) revealed the values obtained at Chiba City c. 70 years ago do not differ greatly from those occurring at the present time. Therefore, even though part of the H. amaurotis population has begun to breed in the plain regions in west-southern districts in Japan over the past 70 years, the migration status has remained unchanged. During each migration period, the number of migrating birds showed at least two peaks. The mean time at which peaks occurred differed between days, suggesting that the site at which each flock had started to fly was respectively different. Flocks arrived from the northwest and departed in a southeasterly direction, and the variance of the direction was very small. As this direction is parallel to the coastline at Chiba City, the birds may fly along the coastline towards the southern part of Boso peninsula where Chiba City is located. However, some flocks may visit forests en route, and remain there for a time. Therefore, autumn migrating flocks of H. amaurotis are thought to show a flexible behaviour responding to environmental conditions.

西表島のアカメガシワ Ｍａｌｌｏｔｕｓ ｊａｐｏｎｉｃｕｓ 果実を採食する鳥

Possible seed dispersal agents of a pioneer tree Mallotus japonicus were observed on Iriomote Island in the summer of 2003. When the fruit is ripe, the shell opens and exposes a clump of blackish lipid-rich seeds. The seeds attract many species of birds. Observation for four days (34hrs) at the tree stands revealed four species of birds, the Jungle Crow Corvus macrorhynchos osai, the Japanese White-eye Zosterops japonicus loochooensis, the Brown-eared Bulbul Hypsipetes amaurotis stejnegeri, and the Emerald Dove Chalcophaps indica yamashinai, to visit and eat the seeds. These endemic sub-species of birds are regarded as important seed dispersers of this pioneer tree.

Fruiting of fleshy-fruited plants and abundance of frugivorous birds: Phenological correspondence in a temperate forest in central Japan

We investigated the seasonal correspondence between the fruiting phenology of fleshy-fruited plants and the abundance of frugivorous birds, in a temperate forest, in central Japan. The majority of fleshy fruits ripened in the fall when frugivorous birds were most abundant. This correspondence occurred earlier than in a warm temperate forest, located in southern Japan; these relationships in East Asia coincide with those of the temperate regions of North America and Europe. We also examined whether the abundance of frugivorous birds led to profitable effects for seed dispersal among fleshy-fruited plants. The Brown-eared Bulbul Hypsipetes amaurotis was considered to be an important seed disperser for many fleshy-fruited plants because of its high frequency of occurrence throughout the fruiting season, and its large gape size, which allowed it to swallow all sizes of fruits found at the study site. Although numerous Brown-eared Bulbuls and other frugivorous birds were present in the fall, fruit removal rates in fall-fruiting species were not always higher than in summer-fruiting species. The abundance of frugivorous birds alone could therefore not adequately explain the concentrated fruiting phenology among fleshy-fruited plants.

Seed dispersal of Chinese tallow-tree Sapium sebiferum by Birds

Fruit of the Chinese tallow-tree Sapium sebiferum have white sarcocarp and dehiscence in autumn. The sarcocarp dries on the branch soon after the dehiscence. We observed eight bird species eating the fruit of S. sebiferum. Two species of crows Corvus corone and C. macrorhynchos, the Grey Starling Sturnus cineraceus and the Brown-eared Bulbul Hypsipetes amaurotis swallowed the fruit and excreted the seeds. The Tree Sparrow Passer montanus, the Great Tit Parus major and the Oriental Greenfinch Carduelis sinica took only a small part of the sarcocarp and left the seeds on the branch.The Turtle Dove Streptopelia orientalis took a lot of fruits and digested the seeds.The Tree Sparrow, the Great Tit, the Oriental Greenfinch, and the Turtle Dove are not seed dispersers, but a kind of seed parasite or predator.

Winter Bird Survey on the Ullung Island, South Korea

Winter bird survey was conducted along the climbing path and the road along the coast of the Ullung Island, from 12 to 19 January, 1995. During the survey a total of 786 birds belonging to 16 species, 14 families, and 6 orders, were observed. Among them, dominant species were Black-tailed Gull Larus crassirostris (7.81/km, 41.4%), Great Tit Parus major dageletensis (4.13/km, 24.7%), Brown-eared Bulbul Hypsipetes amaurotis (2.17/km, 13.0%), Yellow-throated Bunting Emberiza elegans (1.62/km, 9.7%), and Tree Sparrow Passer montanus (1.60/km, 9.5%). Tree Sparrows were recorded in Hyonpo only. The occurrence of Tree Sparrows may be related with food supply and snow cover in winter on the Ullung Island. Russet Saprrow Passer rutilans reported as a resident in South Korea, was not found during the survey.

Flight distance in relation to flock size in the Brown-eared Bulbul Hypsipetes amaurotis

Flight distance in relation to flock size in the Brown-eared Bulbul Hypsipetes amaurotis

Higher ratio of cabbage leaves injured by the Brown-eared Bulbul Hypsipetes amaurotis near shelter belt

In order to determine factors which cause the variation of the ratio of cabbage leaves injured by Hypsipetes amaurotis, I counted the number of leaves injured and not injured for 10 cabbages sampled randomly from each ridge, and calculated the ratio of leaves injured. Analyses of linear regression showed that the ratio of cabbage leaves injured was higher near shelter belt.

BIRD SURVEY OF MT. KISOKOMA, CENTRAL HONSHU

Mt. Kisokoma (2, 956m above the sea level) is the highest peak of the Chuo Alps, Central Honshu. The east side of it is classified into three zones, that is to say, mixed decidious forest at the altitudes of 900-1, 650m, coniferous forest and Betula Ermani zone at 1, 650-2, 600m, dwarf forest Pinus pumila to rocky zones at 2, 600-2, 956m.Bird censuses were made in. alpine zone 2, 612-2, 910m at altitude, throughout the year from middle of February, 1977 to early in February, 1978. This study was conducted by the use of line transect method, along the climbing route.14 species, 9 families of birds were recorded. I could not observe even one bird, during the days from late in November 1977 to middle of April 1978. Brown-eared Bulbul Hypsipetes amaurotis, Great tit Parus major and Brambling Fringilla montifringilla were observed crossing over the ridge above 2870m at altitude. As the passage of breeding season on the census line, Alpine Accentor Prunella collaris and Japanese Accentor Prunella rubida had been decreasing in number gradually.