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Various avian species give mobbing calls that draw conspecific and heterospecific individuals to react against the potential predator. According to the ‘attract the mightier’ hypothesis, when predators appear, prey will produce mobbing calls to attract superior predators to repel or kill the primary predator. To test this hypothesis, we broadcast calls from light-vented bulbuls, Pycnonotus sinensis (the prey) in the vicinity of a taxidermy model of a collared scops owl, Otus lettia (the primary predator). Three call types were used: the typical call (TC, the control treatment), a mobbing call to a collared scops owl (the MtO treatment) and a mobbing call to a crested goshawk, Accipiter trivirgatus (the superior predator; the MtH treatment). Our results showed that crested goshawks appeared and attacked the taxidermy model during the MtO treatment, but not during the control or MtH treatment. The difference between the MtO and other treatments was significant. Our results, therefore, provide strong evidence for the hypothesis that mobbing calls to primary predators can successfully attract superior predators to harm primary predators.

Birds are at a higher level in the food chain; however, the potential bioaccumulation and biotransformation of arsenic (As) in birds in As mines has rarely been studied. In this study, four passerine bird species (tree sparrow [Passer montanus], light-vented bulbul [Pycnonotus sinensis], Garrulax canorus [Leucodioptron canorus], and magpie [Pica pica]) were collected from an abandoned As mine in China. The highest recorded As concentrations were 4.95 mg/kg and 51.65 mg/kg in muscles and feathers, respectively. Detection using high-performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) revealed six As species, including arsenite (As(III)), arsenate (As(V)), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), arsenobetaine (AsB) and arsenocholine (AsC), with the former three species as the dominant (92%) and the latter three as the minor As species (6.17%). Further analysis of the selected bird samples using the X-ray absorption near edge structure (XANES) technique revealed the existence of As(III)-tris-glutathione (As(III)-GSH), which can be regarded as equivalent to the non-extractable and unidentified As form in the HPLC-ICP-MS data. Both methods revealed similar patterns of As species in the birds from the As mine, with muscles containing mainly inorganic As and DMA and feathers containing mainly inorganic As. The results of this study contribute to the knowledge regarding As accumulation and speciation in terrestrial organisms.

Background Food is an important environmental factor that affects animals’ energy metabolism and food shortage has significant effects on animals’ behavior, physiology and biochemistry. However, to date few studies have focused on the thermogenesis and its effects on the body condition of birds. In this study, we examined the effects of food restriction on the body mass, basal metabolic rate (BMR) and body composition, and several physiological, biochemical and molecular markers potentially related to thermogenesis, in the Chinese Bulbul (Pycnonotus sinensis). Methods Birds in the control group were provided with food ad libitum whereas those in the food restriction group were provided with one-half of the usual quantity of food for 12 days. Oxygen consumption was measured using an open-circuit respirometry system. Mitochondrial state 4 respiration and cytochrome c oxidase (COX) activity in the liver and pectoral muscle were measured with a Clark electrode. Avian uncoupling protein (avUCP) mRNA expression was determined in pectorals muscle with quantitative Real-time PCR. Results Chinese Bulbuls in food restriction group decreased in body mass, BMR and internal organ (heart, kidneys, small intestine and total digestive tract) mass compared with the control group over the 12-day period of food restriction. Bulbuls in the food restriction group also had lower levels of state-4 respiration, COX activity in the liver and muscle, and mitochondrial avUCP gene expression in muscle compared to the control group. BMR was positively correlated with body mass, state 4 respiration in the liver and COX activity in the muscle. Conclusions Our data indicate that Chinese Bulbuls not only sustain food shortage through simple passive mechanisms, such as reducing body and organ mass and energy expenditure, but also by reducing energetic metabolism in the liver and muscle.

Food resources play an important role in the regulation of animals' physiology and behavior. We investigated the effect of short-term food restriction on metabolic thermogenesis of Chinese bulbuls (Pycnonotus sinensis) by measuring changes in body mass, body fat, basic metabolic rate (BMR), and organ mass of wild-caught Chinese bulbuls from Wenzhou, China. Short-term food restriction induced a significant decrease in body mass and body fat but body mass returned to normal levels soon after food was no longer restricted. Food restriction caused a significant reduction in BMR after 7 days (P

Seasonal changes in temperature and photoperiod are important environmental cues used by small birds to adjust their body mass (Mb) and thermogenesis. However, the relative importance of these cues with respect to seasonal adjustments in Mb and thermogenesis are difficult to distinguish. In particular, the effects of temperature and photoperiod on energy metabolism and thermoregulation are not well known in many passerines. To address this problem, we measured the effects of temperature and photoperiod on Mb, energy intake, resting metabolic rate (RMR), organ mass and physiological and biochemical markers of metabolic activity, in the Chinese bulbul (Pycnonotus sinensis). Groups of Chinese bulbuls were acclimated in a laboratory to the following conditions: (1) warm and long photoperiod (WL; 30°C, 16 light: 8 dark), (2) warm and short photoperiod (WS; 30°C, 8 light: 16 dark), (3) cold and long photoperiod (CL; 10°C, 16 light: 8 dark), and (4) cold and short photoperiod (CS; 10°C, 8 light: 16 dark), for 4 weeks. The results indicate that Chinese bulbuls exhibit adaptive physiological regulations when exposed to different temperatures and photoperiods. Mb, RMR, gross energy intake (GEI) and digestible energy intake (DEI) were higher in cold acclimated than in warm acclimated bulbuls, and in short photoperiod than in long photoperiod. The resultant flexibility in energy intake and RMR allows Chinese bulbuls exposed to different temperatures and photoperiods to adjust their energy balance and thermogenesis accordingly. Cold acclimated birds had heightened State-4 respiration and cytochrome c oxidase (COX) activity in their liver and muscle tissue compared to warm acclimated birds. Changes in state-4 respiration and COX activity in liver and muscle are cellular mechanisms underlying adaptive thermogenesis in bulbuls. Temperature appears to be a primary cue for adjusting energy budget and thermogenic ability in Chinese bulbuls, photoperiod appears to intensify temperature induced changes in energy metabolism and thermoregulation.

Temperature is an important environmental cue for the regulation of thermogenesis in small birds. We tested the hypothesis that a small passerine, the Chinese bulbul Pycnonotus sinensis can decrease thermogenesis in response to warmer temperatures by decreasing body mass, the organ mass and changing physiological and biochemical processes in the liver and muscle. Captive Chinese bulbuls decreased in body mass and basal metabolic rate (BMR) during 4 weeks of acclimation to 30±1 °C. They also showed a decrease in liver, kidney and small intestine mass and reduced mitochondrial state-4 respiration and cytochrome C oxidase (COX) activity in the liver and muscle compared to 10±1 °C. Furthermore, BMR was positively correlated with body mass, organ mass (liver, kidney, small intestine and entire digestive tract), and mitochondrial state-4 respiration and cytochrome C oxidase (COX) activity in the liver and muscle. These results indicate that changes in body mass, organ mass and respiratory enzyme activity are mechanisms by which Chinese bulbuls adapt to warmer temperatures. The data support the hypothesis that such physiological flexibility is ubiquitous in birds.

Aim Two alternative genetic patterns are typical in recently established populations. One is reduced genetic diversity but significant population structuring compared with original populations. The other is the persistence of genetic polymorphisms and the lack of differentiation in frontier populations. This study aims to test for these patterns by examining population genetics of the Light-vented Bulbul (Pycnonotus sinensis), an Oriental bird that has been undergoing rapid range expansion. Location Eastern China. Methods Molecular analyses were conducted on mitochondrial DNA and microsatellite datasets from 256 individuals. Intraspecific phylogeny was reconstructed by Bayesian inference and network analysis. Analysis of molecular variance (AMOVA) and Bayesian clustering were applied to determine population structure. Genetic diversity was tested to determine whether there were significant differences between frontier and source populations. Population expansions were tested in mtDNA and microsatellites. Gene flow and recent migrants were estimated by Bayesian methods. Results Both high- and low-nucleotide diversities were recorded in frontier populations, and differences in genetic diversity between frontier and source populations were not statistically significant. Population differentiation was recorded in some source but not in frontier populations. Population size expansion was detected both in frontier and in source populations, and for the whole dataset, commencing before the Last Glacial Maximum. Main conclusions Genetic diversity can be maintained in expanding populations of the Light-vented Bulbul, and genetic differentiation can be avoided, where substantial genetic exchanges are occurring. This study also discusses the potential effects of evolutionary properties such as historical population growth on recently recorded range expansion.

In this study, we present the complete mitochondrial genome of P. s. hainanus, which is spread over Hainan Island, southern China and northern Vietnam, containing 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA genes (srRNA and lrRNA) and 2 extensive heteroplasmic control regions. All protein-coding, rRNA genes have more than 99.0% nucleotide sequence similarity with the previously reported individual of P. s. formosae, except for cox3 and CRs. Notably, we found that the nucleotide sequence of P. s. formosae mtDNA has more similarity with P. taivanus.

Sequences of the partial 293-bp nuclear Z-chromosome-linked chromo-helicase binding protein (CHD-Z) and 729-bp mitochondrial cytochrome b (cyt b) genes were obtained from two species of the same family Pycnonotidae of Pycnonotus sinensis (P. sinensis, Chinese Bulbul) and Pycnonotus taivanus (P. taivanus, Taiwan Bulbul) distributed in Taiwan. A panel of 10 individuals (n = 5 for each) with unknown relationship was used to characterize single nucleotide polymorphisms (SNPs) of these genes. We identified 2 and 10 SNPs in CHD-Z and cyt b loci, respectively. Frequency of SNPs was 10 per every 1465- and 729-bp on average. Pairwise nucleotide divergences of CHD-Z and cyt b genes among 10 specimens ranged from 0 to 0.0034 and 0 to 0.0055, respectively. Phylogenetic analysis suggested that the P. taivanus group assignment based on the CHD-Z and cyt b sequences is obviously very similar to P. sinensis.

Urbanization changes the abundance and type of resources upon which birds depend, including the type and availability of nesting materials. Although more and more bird species worldwide are colonizing and adapting to urban environments, the ecological processes underlying the responses to urbanization and the relevant resource changes remain unclear. Here we examined the responses of the Chinese Bulbul Pycnonotus sinensis to urbanization by assess- ing nest composition and available nesting materials at five land-use categories (mountains, farmlands, riparians, urban parks, strips of street trees) of intensifying development in Hangzhou, China. In each land-use category, we classified used and available nesting materials as anthropogenic (e.g. plastics, paper pieces, cloth pieces, nylon particles, threads) or natural materials (e.g. plant culms, roots, leaves). We found that the proportion of anthropogenic nesting materials used by Chinese Bulbuls differed significantly across land-use categories, and it increased significantly with urbaniza- tion. Additionally, the increasing amount of anthropogenic nesting materials with urbanization can be attributed to an increase in the availability of anthropogenic nesting materials toward the urban core. Our results indicate that Chinese Bulbuls can adjust the composition of their nests in response to urbanization.

The Chinese yew (Taxus chinensis) is catalogued as an endangered species in China because of the small size and senescent status of most populations. Its lack of natural regeneration is the most important reason for its endangered status. We investigated the regeneration of an ex-situ conservation population, which was introduced into the Nanjing Botanical Garden Memorial Sun Yat-Sen in the 1950s, and evaluated the role of frugivorous birds on the establishment of this regenerating population. Two hundred and thirteen individual yew seedlings and saplings were found on the hillside in 2006, and the nearest seedling was found more than 10 m away from mother trees. The spatial pattern of all seedlings and saplings occurred as a clumped distribution, which is typical for vertebrate-dispersed plants. Six bird species were seen ingesting whole "fruits" at yew trees in the present study and 745 visits by avian frugivores were recorded. Red-billed blue magpie (Urocissa erythrorhyncha), Chinese bulbul (Pycnonotus sinensis) and azure-winged magpie (Cyanopica cyana) were the most frequent visitors over the two years of the study. Comparing the flights of departure and perching habitats of the three main bird species, we inferred that U. erythrorhyncha would be the most important disperser. This regeneration population has had good development over the past 20 or more years; frugivorous birds have removed seeds to the hillside every year until now, and seed germination and seedling growth continue to develop well under natural conditions. We suggest that the conservation system of the Chinese yew should be composed of yews, avian dispersers and habitats for seed germination and seedling growth.

1 Seasonal changes in a bird's physiology and behavior are considered to be a part of an adaptive strategy for survival and reproductive success. To understand modes of metabolic adaptations, the metabolic rate ( V o 2 ), body temperature ( T b ), and thermal conductance ( C ) of the Chinese bulbul ( Pycnonotus sinensis ) in the Zhejiang Province of China were determined in the summer and the winter at a temperature range from 5 to 35 °C, respectively. 2 The thermal neutral zone (TNZ) of the Chinese bulbul was between 26 and 33 °C in the summer and between 25 and 32.5 °C in the winter. With a temperature range from 5 to 35 °C, the mean T b was 40.3±0.1 °C and 40.2±0.1 °C, in the summer and in the winter, respectively. Minimum C was 0.24±0.01 ml O 2 g −1 h −1 °C −1 in the summer and 0.25±0.01 ml O 2 g −1 h −1 °C −1 in the winter. 3 The mean basal metabolic rate within TNZ was 2.86±0.16 ml O 2 g −1 h −1 in the summer and 3.36±0.12 ml O 2 g −1 h −1 in the winter. 4 Chinese bulbuls showed seasonal metabolic acclimatization similar to other temperate wintering passerines. This improved cold tolerance was associated with a significant increase in V o 2 (18%) in the winter relative to the summer.

We studied the composition of a secondary forest bird community in Hong Kong (22°N) between December 1992 and June 1995, using the variable point count method. The visual detectability of each bird species had a significant positive relationship with body length. A total of 71 bird species was recorded but three resident habitat-generalists, the Great Tit Parus major, Light-vented Bulbul Pycnonotus sinensis and Japanese White-eye Zosterops japonicus, accounted for 65% of the mean total bird density of 38 per ha. The number of species seen was highest between December and April and lowest from July to September, but the total bird density was highest between December and June and lowest from August to September. The main breeding season was from March to August. Insectivores and insectivore-frugivores accounted for 80% of the species and 98% of the total bird density. The percentages of migrant species and individuals are similar to those reported at equivalent latitudes in North America. Bird community diversity and composition differed considerably from that of larger, older forest areas in South China, presumably as a result of differences in forest age, area and isolation.

論文

Knowledge is limited about the bioaccumulation of persistent halogenated compounds (PHCs) in terrestrial wildlife. Several PHCs, including dichlorodiphenyltrichloroethane (DDT) and its metabolites (designated as DDTs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenylethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), and stable isotopes (δ(15)N and δ(13)C) were analyzed in the muscle of four terrestrial passerines, Parus major, Copsychus saularis, Pycnonotus sinensis and Pycnonotus jocosus, from a nature reserve in South China. P. major had the highest PHC concentrations, with median values of 1060, 401, 92, 25 and 0.3 ng/g lipid weight for DDTs, PCBs, PBDEs, DBDPE and BTBPE, respectively. Fractions of DDT in P. jocosus and PCBs 153, 118 and 180 in C. saularis were higher compared with the other species. The inter-species differences in PHC concentrations and profiles could be attributed to the differences in trophic level, diet, living habits and metabolic capacity among the birds.

論文

論文

Although a number of studies have addressed the bioaccumulation of Dechlorane Plus (DP) flame retardant in wildlife, few data are available on terrestrial organisms. This study examined the presence of DP isomers in the muscle tissue of seven terrestrial resident passerine species, i.e., the great tit (Parus major), the oriental magpie-robin (Copsychus saularis), the red-whiskered bulbul (Pycnonotus jocosus), the light-vented bulbul (Pycnonotus sinensis), the streak-breasted scimitar babbler (Pomatorhinus ruficollis), the long-tailed shrike (Lanius schach), and the orange-headed thrush (Zoothera citrina), from a national nature reserve located in South China. The ∑DP (sum of syn-DP and anti-DP) concentrations ranged from 1.2 to 104 ng/g lipid weight, with significantly higher levels in insectivorous birds than in omnivorous birds. The overall exposure to DP isomers of the current passerines may be attributed to the intensive release of this pollutant from electronic waste recycling sites and industrial zones in the vicinity of the nature reserve. Species-specific DP isomeric profiles were also found, with significantly greater fanti values (the isomer fractions of anti-DP) in the red-whiskered bulbul and the oriental magpie-robin. Additionally, the fanti values were significantly negatively correlated to ∑DP concentrations for the individual bird samples, suggesting the influence of DP concentrations on the isomeric profiles.

Survival of small birds in fluctuating environments is facilitated by seasonal metabolic and morphological flexibility. Chinese bulbuls Pycnonotus sinensis show winter increases in resting metabolic rate (RMR), nutritional organ masses, and liver and muscle cellular aerobic capacity relative to summer. In this study, we build on these findings from previous studies by measuring seasonal adjustments in body mass (Mb), RMR, nutritional and exercise organ masses, and several physiological, biochemical, and hormonal markers over the entire annual cycle in wild-trapped Chinese bulbuls from Wenzhou, China. Furthermore, we analyzed the relationships between variation in organ masses and cellular aerobic capacity and variation in RMR in individual birds. Mb and RMR were higher in spring (March-May) and winter (December-February) than in summer (June-August). The dry masses of several nutritional organs and mitochondrial protein content, state 4 respiration, and cytochrome c oxidase (COX) activity in liver and muscle were all heightened in winter relative to other seasons. In addition, dry masses of heart and pectoral muscle, but not nutritional organs, and biochemical markers of cellular aerobic capacity in liver and muscle were positively correlated with RMR. Plasma triiodothyronine (T3) concentration was higher in winter and spring than in summer and autumn, and it was positively correlated with RMR, mitochondrial protein content, state 4 respiration, and COX activity in liver and muscle. These results suggest that seasonal changes in nutritional and exercise organ masses and liver and muscle cellular aerobic capacity interact to promote seasonal metabolic flexibility in Chinese bulbuls. T3 appears to promote these seasonal thermoregulatory adjustments.

Thirty-two light-vented bulbuls (Pycnonotus sinensis) were collected from six sampling sites in Guangdong Province, South China to investigate the geographical variation on the occurrence of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs). Concentrations of PCBs and DDTs in the pectoral muscle of light-vented bulbul ranged from 140 to 73,000 ng/g lipid weight (lw) and 12 to 4600 ng/g lw, respectively. PCB concentrations were significantly higher in birds from e-waste site compared to other sampling sites (mean, 18,000 vs 290 ng/g lw, p0.0001), implying that PCBs mainly came from e-waste recycling activities. No significant differences for DDT levels were observed among the sampling sites (p=0.092). Differences in PCB homologue profiles among the sampling sites were found and can be probably ascribed to different local contamination sources. p,p'-DDE (80%) was the most abundant component of DDTs in birds. Compositional pattern of DDTs suggested that historical residue was the main source of DDT. The toxic equivalent (TEQ) concentrations had significant positive correlations with PCB concentrations, indicating that elevated PCB levels may have adverse effects on light-vented bulbuls.

シロガシラによる農作物への被害は,冬期の餌果実の量に影響されると考え,シロガシラの個体数と野生果実の着果量について調べた。これをふまえて被害との関係を検討した。野生植物として,年中実をつけるガジュマルを選んだ。都市部における個体数は春から秋の繁殖期には比較的多く,冬の非繁殖期には野生果実の着果量が多いときに多くなったが,野生果実と単純には関連していないと考えられる。対照的に農村部では個体数は繁殖期に少なく,非繁殖期に多かった。群れサイズはどちらの場所でも非繁殖期である冬に大きくなった。農作物への被害は,冬期にガジュマルの実が少ない年に多かったことからガジュマルの着果量が被害に影響している可能性がある。しかし,今後他の野生餌植物との関係を調査し,さらなるデータを蓄積する必要がある。

The light-vented bulbul Pycnonotus sinensis is a small resident passerine that is found widely in central and south China, North Vietnam, and some East Asian islands, including Hainan, Taiwan and the Ryukyu Islands. Its subspecies status has been under considerable debate. A total of 10 subspecies have been proposed, but only 4 are widely recognized, including 1 continental taxon, P. s. sinensis, and 3 insular subspecies: P. s. hainanus, P. s. formosae and P. s. orii. Two mitochondrial DNA genes and 9 microsatellite loci were used to investigate the genetic divergence of this species, to identify the evolutionary status of 2 insular subspecies (P. s. hainanus and P. s. formosae) and to uncover probable historical causes that shaped them. The results reveal that P. s. formosae has diverged significantly from the other 2 subspecies because of a substantial time of isolation for populations on Taiwan Island. There was no significant genetic differentiation between P. s. sinensis and P. s. hainanus. The notable morphological difference in P. s. hainanus might be attributed to a rapid, recent adaptation to the tropical environment of Hainan Island. The low genetic divergence between P. s. sinensis and P. s. hainanus might result from a recent divergence or gene flow between them. Two insular subspecies of light-vented bulbul populations might have diverged recently from their continental relatives through a complex evolution history owing to island isolation, ecological isolation, and possibly even hybridization. Both P. s. hainanus and P. s. formosae should be considered important conservation units because of their morphological and genetic distinctiveness.

Five new species of the genus Pteroherpus Gaud, 1981 are described from different passerine birds of Vietnam: Pteroherpus krivolutskii n.sp. from Stachyris nigriceps Blyth, P. zosteropis n.sp. from Zosterops japonica Temminck, P. dentilobus n.sp. from Timalia pileata Horsfield, P. pycnonoti n.sp from Pycnonotus sinensis (Gmelin), and P. orthotomi n.sp. from Orthotomus sutorius (Pennant).

43 species of digenetic trematodes of birds are reported from Taiwan. One new family, one new subfamily, two new genera, and nine new species are described: Taiwantrematidae fam. n. Taiwantrema arborophilae gen. et sp. n. from Arborophila crudigularis; Cyclocoelidae, Morishitium taiwanense sp.n. from A. crudigularis; Eucotylidae, Tanaisia (Tamerlania) taiwanensis sp. n. from A. crudigularis; Brachylaimidae, Leucochloridium taiwanense sp. n. from A. crudigularis; Echinostomatidae, Echinostoma taiwanense sp. n. from Zosterops japonica simplex; Dicrocoeliidae, Concinnum taiwanense sp. n. from Pycnonotus taivanus; Lecithodendriidae, Pseudocryptotropa formosae sp. n. from Pycnonotus sinensis formosae; Microphallidae, Promicrophallinae subfam. n. Promicrophallus taiwanensis gen. et sp. n. from A. crudigularis; Opisthorchiidae, Metametorchis taiwanensis sp. n. from the domestic duck.

Seasonal adjustments in body mass and energy budget are important for the survival of small birds in temperate zones. Seasonal changes in body mass, body temperature, gross energy intake (GEI), digestible energy intake (DEI), body fat content, as well as length and mass of the digestive tract, were measured in Chinese Bulbuls (Pycnonotus sinensis) caught in the wild at Wenzhou, China. Body mass was determined with a Sartorius balance. The caloric contents of the dried food and feces were then determined using a oxygen bomb calorimeter. Total fat was extracted from the dried carcasses by ether extraction in a Soxhlet apparatus. The digestive tract of each bird was measured and weighed, and was then dried to a constant mass. Body mass showed a significant seasonal variation and was higher in spring and winter than in summer and autumn. Body fat was higher in winter than in other seasons. GEI and DEI were significantly higher in winter. The length and mass of the digestive tract were greatest in winter and the magnitude of both these parameters was positively correlated with body mass, GEI and DEI. Small passerines typically have higher daily energy expenditure in winter, necessitating increased food consumption. This general observation is consistent with the observed winter increase in gut volume and body mass in Chinese Bulbuls. These results suggest that Chinese Bulbuls adjust to winter conditions by increasing their body mass, body fat, GEI, DEI and digestive tract size.