Fat and body condition in migrating Redwings Turdus iliacus

During the night of 29–30 October 1995, over 600 Redwings Turdus iliacus died as a result of flying into the lighthouse at Bardsey, Gwynedd, North Wales. These migrating birds were used to investigate fat levels in relation to age, sex, biometrics and pectoral muscle mass. Wing length was the best single linear measure of size and mean wing length of males was 2.5 mm greater than that of females. Body mass of the casualties declined during the night and the mean body mass of birds arriving towards the end of the night was 1.5 g lower than that of the first arrivals. Fat deposits at different body sites were significantly correlated with each other and with body mass, and, by extrapolation, the mass of intra-abdominal fat remaining would be significant when other fat deposits have been depleted. Fat in the tracheal pit (the claviculo-coracoid fat body) demonstrated the best correlation with body mass and was linearly correlated with visual fat scores. Fat was also present in the pectoral muscle but did not make a significant contribution to overall body mass. Two-thirds of the variation in body mass was accounted for by wing length, the mass of claviculo-coracoid fat and the lean-dry mass of pectoral muscle. Claviculo-coracoid fat and lean pectoral-muscle mass contributed independently to overall body mass. These data support the view that increase in fat in relation to migration is accompanied by an increase in protein or lean muscle mass, but suggest that these are controlled independently.     

Ultraviolet reflection of berries attracts foraging birds. A laboratory study with redwings (Turdus iliacus) and bilberries (Vaccinium myrtillus)

Unlike humans, birds perceive ultraviolet (UV) light (320 to 400 nm), a waveband which is known to play a role in avian mate choice. However, less attention has been paid to the role of UV light in avian foraging. Some blue, violet and black berries reflect UV light. The colour of berries might be an effective advertisement for avian seed dispersers and indicate the stage of fruit ripeness. We conducted an experiment to test how the UV reflection of berries affects birds'' foraging. Redwings were allowed to choose between UV-reflecting bilberries and rubbed bilberries (UV reduced) in the presence and absence of UV light. We used wild-caught adult and hand-raised juvenile birds to assess possible differences between experienced and naive birds. We found that adult redwings preferred UV-reflecting berries when UV illumination was present, but when UV illumination was absent, they did not distinguish between the two berry types. Our study therefore shows, for the first time, that UV wavelengths are used when birds feed on fruit. However, naive birds showed no preferences, suggesting that age and/or learning may affect frugivore preference for UV reflectance.     

江苏南京发现赤颈鸫和宝兴歌鸫?

正2013年3月31日,在江苏省南京市老山九峰寺附近(118°89'21E,31°32'75N)发现1只在林间地面活动的鸫类,并拍摄照片(图1a)。所拍摄的个体上体灰褐色,眉纹、颈侧、喉及胸为红褐色,腹部和尾下覆羽为白色,根据相关资料(约翰·马敬能等2000)鉴定为赤颈鸫(Turdus ruficollis)雄性个体。2015年11月11日再次于南京老山发现赤颈鸫。     

Cere Colour as a Basis for Extra-pair Preferences of Paired Male Budgerigars (Melopsittacus undulatus: Psittacidae: Aves)

Male budgerigars may be limited in the time they have available to pursue extra-pair copulations because of conflicts with other reproductive behaviour. If males could selectively court only immediately fertilizable extra-pair females they should do so. The cere colour of a female budgerigar may be used as a cue to her reproductive readiness. We experimentally tested the hypothesis that males prefer females with dark ceres, which are indicative of developed ovaries, over females with light-coloured ceres, characteristic of birds with undeveloped ovaries. In a pairwise choice experiment between females that had their cere colour artificially manipulated, pair-bonded males were more likely to choose the female with the dark-coloured cere.     

Mitochondrial Haplogroup T Is Associated with Obesity in Austrian Juveniles and Adults

Background

Recent publications have reported contradictory data regarding mitochondrial DNA (mtDNA) variation and its association with body mass index. The aim of the present study was to compare the frequencies of mtDNA haplogroups as well as control region (CR) polymorphisms of obese juveniles (n = 248) and obese adults (n = 1003) versus normal weight controls (n_juvenile = 266, n_adults = 595) in a well-defined, ethnically homogenous, age-matched comparative cohort of Austrian Caucasians.

Methodology and Principal Findings

Using SNP analysis and DNA sequencing, we identified the nine major European mitochondrial haplogroups and CR polymorphisms. Of these, only the T haplogroup frequency was increased in the juvenile obese cohort versus the control subjects [11.7% in obese vs. 6.4% in controls], although statistical significance was lost after adjustment for sex and age. Similar data were observed in a local adult cohort, in which haplogroup T was found at a significantly higher frequency in the overweight and obese subjects than in the normal weight group [9.7% vs. 6.2%, p = 0.012, adjusted for sex and age]. When all obese subjects were considered together, the difference in the frequency of haplogroup T was even more clearly seen [10.1% vs. 6.3%, p = 0.002, OR (95% CI) 1.71 (1.2–2.4), adjusted for sex and age]. The frequencies of the T haplogroup-linked CR polymorphisms C16294T and the C16296T were found to be elevated in both the juvenile and the adult obese cohort compared to the controls. Nevertheless, no mtDNA haplogroup or CR polymorphism was robustly associated with any of several investigated metabolic and cardiovascular parameters (e.g., blood pressure, blood glucose concentration, triglycerides, cholesterol) in all obese subjects.

Conclusions and Significance

By investigation of this large ethnically and geographically homogenous cohort of Middle European Caucasians, only mtDNA haplogroup T was identified as an obesity risk factor.     

Mental Health Help-Seeking Intentions and Preferences of Rural Chinese Adults

Purpose

We aimed to investigate mental health help-seeking intentions and preferences of rural Chinese adults and determine predictors of the intentions.

Methods

A total of 2052 representative rural residents aged 18–60 completed a cross-sectional survey by face-to-face interviews. The survey included seven questions asking about respondents’ help-seeking intentions and preferences, and a series of internationally validated instruments to assess self-perceived health status, depression, anxiety, alcohol abuse, mental health literacy, and attitudes towards mental illness.

Results

Nearly 80% of respondents were willing to seek psychological help if needed, and 72.4% preferred to get help from medical organizations, yet only 12% knew of any hospitals or clinics providing such help. A multivariate analysis of help-seeking intention revealed that being female, having lower education, higher social health, higher mental health knowledge, and physical causal attribution for depression were positive predictors of help-seeking intention.

Conclusion

A huge gap exists between the relatively higher intention for help-seeking and significantly lower knowledge of helpful resources. Predictors of help-seeking intention for mental problems in the current study are consistent with previous studies. Interventions to increase help-seeking for mental problems by Chinese rural adults may be best served by focusing on increasing public awareness of help sources, as well as improving residents’ mental health literacy and social health, with special focus on males and those more educated.     

Comparative behavior of free-ranging blackbirds (Turdus merula) and silvereyes (Zosterops lateralis) with hexose sugars in artificial grapes

In order to detect bird responses to sugar parameters of ripening grapes, artificial grapes containing controlled concentrations of hexose sugars were offered to free-range blackbirds (Turdus merula) and silvereyes (Zosterops lateralis). Time-lapse video was used to observe the two species of birds feeding on grapes presented on a novel two-tier bird-table. The comparative interest displayed by the birds for grapes of varying concentrations of hexose sugars, and the time spent feeding by each species were analyzed statistically, to discover the level of sugar concentration in grapes that is attractive to these birds. Blackbirds exhibited a preference for high sugar concentration, while silvereyes preferred grapes with a lower concentration. Blackbird visits were much shorter than those of silvereyes and they took whole grapes whereas silvereyes pecked. Differences in behavior of the two species are discussed and the assumption that all frugivorous birds are attracted to fruit for similar reasons is challenged. It may be that differences in digestive glucose absorption processes underlie the observed difference in behavioral responses of the two species.     

Orientation and Shape Discrimination in Juveniles and Adults of the Mangrove Crab Aratus pisonii (H. Milne Edwards, 1837): Effect of Predator and Chemical Cues

Behavioral responses of juveniles and adults of the mangrove crab Aratus pisonii (H. Milne Edwards, 1837) to black geometric shapes of equal surface area was measured. Crabs were tested either in presence or absence of chemicals generated from two common predator species, the portunid crab Callinectes ornatus Ordway, and the soapfish Haemulon aurolineatum Cuvier, 1830. The present study tested the hypothesis that A. pisonii (1) has the capacity to orient to visual cues; (2) it discriminates between different visual objects based on a combination of chemical and visual information and (3) this behavior changes with age. When presented with single black targets in background water, juveniles oriented toward all shapes. This behavioral response was interpreted as visual orientation toward potential shelter. Among shapes, juveniles showed preference for the vertical rectangle, probably due to the recognition of natural visual elements like mangrove roots. In predator conditioned water, juveniles exhibited a stronger response than in background water. Thus, juveniles were able to detect by odor the potential presence of predators. Change in responsiveness between adults and juveniles was also demonstrated.     

Orientation and Shape Discrimination in Juveniles and Adults of the Mangrove Crab Aratus pisonii (H. Milne Edwards, 1837): Effect of Predator and Chemical Cues

Behavioral responses of juveniles and adults of the mangrove crab Aratus pisonii (H. Milne Edwards, 1837) to black geometric shapes of equal surface area was measured. Crabs were tested either in presence or absence of chemicals generated from two common predator species, the portunid crab Callinectes ornatus Ordway, and the soapfish Haemulon aurolineatum Cuvier, 1830. The present study tested the hypothesis that A. pisonii (1) has the capacity to orient to visual cues; (2) it discriminates between different visual objects based on a combination of chemical and visual information and (3) this behavior changes with age. When presented with single black targets in background water, juveniles oriented toward all shapes. This behavioral response was interpreted as visual orientation toward potential shelter. Among shapes, juveniles showed preference for the vertical rectangle, probably due to the recognition of natural visual elements like mangrove roots. In predator conditioned water, juveniles exhibited a stronger response than in background water. Thus, juveniles were able to detect by odor the potential presence of predators. Change in responsiveness between adults and juveniles was also demonstrated.     

Loss of migration and urbanization in birds: a case study of the blackbird (Turdus merula)

Many organisms have invaded urban habitats, although the underlying factors initially promoting urbanization remain poorly understood. Partial migration may facilitate urbanization because such populations benefit from surplus food in urban environments during winter, and hence enjoy reduced fitness costs of migratory deaths. We tested this hypothesis in the European blackbird Turdus merula, which has been urbanized since the 19th century, by compiling information on timing of urbanization, migratory status, and population density for 99 cities across the continent. Timing of urbanization was spatially auto-correlated at scales up to 600 km. Analyses of timing of urbanization revealed that urbanization occurred earlier in partially migratory and resident populations than in migratory populations of blackbirds. Independently, this effect was most pronounced in the range of the distribution that currently has the highest population density, suggesting that urbanization facilitated population growth. These findings are consistent with the hypothesis that timing of urbanization is facilitated by partial migration, resulting in subsequent residency and population growth.     

Hypsodonty of Dipodidae (Rodentia) in Correlation with Diet Preferences and Habitats

The evolution of molar teeth from low-crowned (brachyodont) to high-crowned (hypsodont) has traditionally been recognized as a response to increasing tooth wear due to endogenous (e.g., fiber, silica) and/ or exogenous (e.g., dust, grit) properties of ingested food. Recent work indicates that the mean hypsodonty level of large herbivorous land mammalian communities is a strong predictor of precipitation in their habitats. For small mammals, however, the research is still in an early stage. This study performed comparative studies of hypsodonty on 26 extant dipodid species with and without consideration of phylogeny. The results confirm the role of diet in shaping the cheek tooth crown height in Dipodidae. The significant relationship of investigated environmental variables with hypsodonty may be partly due to phylogenetic effects. Nonetheless, the mean hypsodonty of dipodid communities has significant relationship with regional climatic variables. Hence, the hypsodonty of dipodids also has great potential to be a regional climate proxy.     

Sex determination in Turdus amaurochalinus (Passeriformes: Muscicapidae): morphometrical analysis supported by CHD gene

Sex determination is important for conservation and population studies, particularly for reproduction programs of threatened species and behavioural ecology. Turdus amaurochalinus, Creamy-bellied Thrush, only exhibits sexual dimorphism during the breeding season, when males are considered to show intense yellow bills, and females and immature males show dark brown bills. The objectives of this study were: 1) to determine the sex of individuals using genetic techniques, and 2) to test the hypothesis that sex dimorphism can be detected by morphometry. This study was carried out at Parque Nacional da Restinga de Jurubatiba, a preserved area located on the North coast of Rio de Janeiro State. The birds were captured using ornithological nets, singly marked with metal rings, weighed, measured and had blood samples collected before being released. The sex of 42 T. amaurochalinus individuals was determined using the CHD gene marker. A total of 20 males and 22 females were identified from June to August, with peak capture frequency in June. Turdus amaurochalinus females and males differed significantly in morphometrical measures. The most important traits to distinguish males from females were wing length (Student t-test = 4.34, df = 40, p = 0.0001) and weight (Student t-test = 2.08, d f = 40, p = 0.044): females were heavier and had significantly shorter wing length than males. Females and males were correctly classified in 86% and 75% of cases, respectively, using Discriminant Analysis. The molecular analysis was the most secure method for sex determination in the studied species.     

Energetics and metabolite profiles during early flight in American robins (Turdus Migratorius)

Although birds use fat as the primary fuel for migratory flights, carbohydrate and protein catabolism could be significant in the early stages of flight while pathways of fatty acid transport and oxidation are induced. The fuel mixture of long distance migrant birds can also be affected by the rate of water loss, where birds catabolize more protein to increase endogenous water production under dehydrating flight conditions. Despite many studies investigating flight metabolism, few have focused on the metabolic response to flight during the switchover to fat catabolism in migrants, and none have examined the effect of ambient conditions on fuel selection during early flight. We investigated the effect of water loss on the metabolic response to short duration flight in the American robin (Turdus migratorius). Birds were flown in a climatic wind tunnel and changes in body composition and plasma metabolites were measured. As flight duration increased, there was a gradual switchover from carbohydrate and protein catabolism to fat catabolism. Plasma metabolite profiles indicate that the mobilization of fat occurred within 20 min of initiating flight. Plasma glucose decreased and uric acid increased with flight duration. Ambient humidity did not affect fuel mixture. Thus, it seems that the utilization of fat may be delayed as migrants initiate flight. Short-hop migrants may exploit high rates of endogenous water production resulting from carbohydrate and protein catabolism early in flight to offset high water loss associated with low humidity. Rapid catabolism of lean body components at the start of a flight also reduces mass quickly, and may reduce energy costs.     

Fruit and Seed Structures in Menodora (Oleaceae): a Comparison with Jasminum

The fruit development in Menodora agrees largely with that in Jasminum, except for the final stages. The seed coat resembles that of Jasminum in the presence of ribbon-shaped wall thickenings in the mesotestal layers, a character not known from any other Oleaceae. In several characters there is more similarity between Menodora and Jasminum sect. Alternifolia, or between Menodora and J. nudiflorum, than there is among the species of Jasminum. This supports the idea that Jasminum might be paraphyletic, if Menodora is retained as a separate genus.