Effects of the winter beechmast crop on bird occurrence in British gardens

Capsule Woodland birds were significantly less likely to occur in gardens in years of high beechmast crop.

Aim To test the hypothesis that woodland species that feed on beechmast will have significantly lower occurrence rates at garden feeders in mast years.

Methods Weekly winter occurrence rates at garden feeders between 1970/71 and 1999/2000 for 40 species were analysed in relation to annual beechmast abundance, classified into low, medium and high years. A repeated-measures logistic regression model was used to assess whether beechmast abundance explained further significant variation additional to underlying seasonal and annual trends.

Results Seven species that commonly feed on beechmast showed significantly lower occurrence in gardens in years of highest beechmast abundance: Great Spotted Woodpecker Dendrocopos major, Woodpigeon Columba palumbus, Great Tit Parus major, Coal Tit Periparus ater, Nuthatch Sitta europaea, Jay Garrulus glandarius and Chaffinch Fringilla coelebs. Blackbird Turdus merula and Siskin Carduelis spinus, which showed similar significant patterns, are likely to take beechmast as elements of their diet. Pied Wagtail Motacilla alba was the only insectivorous species to show significant effects, but occurrence was lowest in years of intermediate beechmast abundance. For the latter species, this may have been due to confounding effects of temperature, but there were no such confounding effects of either temperature, or the number of bird feeders provided in gardens, for the other nine species.

Conclusion Use of artificial food sources by birds in gardens is influenced by resources in the surrounding countryside, suggesting that food provided in gardens may play a significant part in the population dynamics of these species, that population monitoring without consideration of the garden habitat may be deficient, and that volunteer-based garden bird recording may provide data that can be used as an indicator of changes in the wider countryside.     

Coevolutionary interactions in a host–parasite system

Interactions between parasitic cuckoos and their hosts represent a classic example of coevolution, where adaptations in the parasite to exploit the host select for defences, which in turn select for new parasite adaptations. Current interactions between the two parties may be at an evolutionary equilibrium or, alternatively, a coevolutionary arms race may be taking place. By taking into account the effect of gene flow in 15 European magpie ( Pica pica ) populations, we studied the coevolutionary interactions with its brood parasite, the great spotted cuckoo ( Clamator glandarius ). Our results suggest that, in Europe, magpies and cuckoos are engaged in an ongoing coevolutionary process because, despite controlling for the large amounts of gene flow among different magpie populations, we still found a positive relationship between host defence (i.e. foreign egg recognition and rejection) and parasite selection pressure.     

Methylnaltrexone prevents morphine-induced kaolin intake in the rat

Opioids are frequently used analgesics, and emesis is a common opioid-induced adverse effect. Methylnaltrexone, a peripheral opioid antagonist, has the potential to block the undesired effects of opioids that are mediated by peripheral receptors while sparing the analgesic effect. We used a rat model of simulated emesis or pica to study if methylnaltrexone decreases morphine induced-kaolin consumption. We observed that after morphine administration, kaolin intake increased significantly compared to intake in the vehicle group, and the increase could be attenuated by ondansetron administration. Methylnaltrexone dose-dependently reduced kaolin ingestion induced by morphine. Morphine and methylnaltrexone did not significantly affect food intake and body weight in the experimental animals. Our data suggest that methylnaltrexone has therapeutic value in treating opioid-induced nausea and vomiting.     

A quantitative trait locus for recognition of foreign eggs in the host of a brood parasite

Avian brood parasites reduce the reproductive output of their hosts and thereby select for defence mechanisms such as ejection of parasitic eggs. Such defence mechanisms simultaneously select for counter-defences in brood parasites, causing a coevolutionary arms race. Although coevolutionary models assume that defences and counter-defences are genetically influenced, this has never been demonstrated for brood parasites. Here, we give strong evidence for genetic differences between ejector and nonejectors, which could allow the study of such host defence at the genetic level, as well as studies of maintenance of genetic variation in defences. Briefly, we found that magpies, that are the main host of the great spotted cuckoo in Europe, have alleles of one microsatellite locus (Ase64) that segregate between accepters and rejecters of experimental parasitic eggs. Furthermore, differences in ejection rate among host populations exploited by the brood parasite covaried significantly with the genetic distance for this locus.     

Soil ingestion rates in children identified by parental observation as likely high soil ingesters

Soil ingestion was estimated over seven consecutive days in a soil tracer‐based mass‐balance methodology in 12 children, aged 1 to 3 years. The children had been identified by parents as likely high soil ingesters based on retrospective observation of daily soil ingestion behavior over the past 30 d. While one of the 12 children displayed high soil ingestion (0.5 to 3.05 g/d) on 4 of 7 d, median soil ingestion rates for the 12 children were comparable to those published in other soil ingestion studies of young children selected for studies based on age and not assumed or observed soil ingestion behavior. The lack of ability of parental judgments to predict high soil ingestion rates represents both an important observation and a significant limitation in current methods to efficiently and accurately identify children who ingest high amounts of soil.     

吉林向海自然保护区占用喜鹊巢繁殖的鸟类巢记述

部分鸟类在繁殖过程中,为避免被捕食、减少繁殖投入等而选择占用其他鸟类的巢。2014~2016年每年的4~8月,在吉林向海国家级自然保护区记录到4种占用喜鹊巢进行繁殖的鸟类,其中绿头鸭(Anas platyrhynchos)8巢,纵纹腹小鸮(Athene noctua)4巢,长耳鸮(Aiso otus)5巢,麻雀(Passer montanus)6巢。大部分(82.6%)为利用喜鹊的废弃旧巢,而绿头鸭(1巢)、长耳鸮(2巢)和纵纹腹小鸮(1巢)少数侵占喜鹊当年新建的巢。     

Nesting ecology of solitary‐nesting Amur Falcons (Falco amurensis) in central Mongolia

Amur Falcons (Falco amurensis) are a migratory species that face a variety of threats across their range, but little is known about their breeding ecology. These falcons breed in forest habitats in Eastern and Central Asia using nests constructed by corvids, including Eurasian Magpies (Pica pica). We monitored nests of 21 pairs of Amur Falcons at Hustai National Park in central Mongolia in 2017. Our objectives were to describe their basic nesting ecology, estimate nest survival by modeling the daily survival rate (DSR), examine nest selection by modeling it as a function of nest and site covariates, and use a spatial simulation to test hypotheses concerning intra‐ and interspecific avoidance. Clutch sizes averaged 4.1 eggs (N = 21 nests), and incubation and nestling periods averaged 25.7 and 26.1 d, respectively. The daily survival rate was 0.98, with young in 12 nests surviving to fledging. Nest structures were more likely to be selected as percent cover of nest bowls increased, usually in the form of a dome of sticks with multiple side entrances. Closed nests likely provide increased protection from predators. In contrast to congeneric Red‐footed Falcons (F. vespertinus) that nest in large colonies, Amur Falcons nested no farther from or closer to nests of either conspecifics or congeners than expected by chance. One factor likely contributing to this difference is that Red‐footed Falcons often use the nests of colonial‐nesting Rooks (Corvus frugilegus), whereas Amur Falcons typically use the nests of non‐colonial Eurasian Magpies. The ongoing loss of deciduous trees like white birch (Betula platyphylla) across the breeding range of Amur Falcons, probably due to climate change and increased grazing pressure, is likely to reduce the availability of nesting habitat for Eurasian Magpies which, in turn, will likely reduce availability of nests for Amur Falcons and other small falcons.     

Comparison of a culture‐based and a PCR‐based methods for estimating bacterial abundance on eggshells,with comments on statistical analyses

Field ornithologists have used traditional culture‐based techniques to determine the presence and abundance of microbes on surfaces such as eggshells, but culture‐independent PCR‐based methods have recently been introduced. We compared the traditional culture‐based and the real‐time PCR‐based methods for detecting and quantifying Escherichia coli on the eggshells of Eurasian Magpies (Pica pica). PCR estimates of bacterial abundance were ～10 times higher than culture‐based estimates, and the culture‐based technique failed to detect bacteria at lower densities. When both methods detected bacteria, bacterial densities determined by the two methods were positively correlated, indicating that both methods can be used to study factors affecting bacterial densities. The difference between the two methods is consistent with generally acknowledged higher sensitivity of the PCR method, but the extent of the difference in our study (10×) may have been influenced by both a PCR‐based overestimation and culture‐based underestimation of bacterial densities. Our results also illustrate that bacterial counts may sometimes produce left‐censored data (i.e., we did not detect E. coli in 62% of our samples using the culture‐based method). Specific statistical methods have been developed for analyzed left‐censored data, but, to our knowledge, have not been used by ornithologists. In future studies, investigators studying bacterial loads should provide information about the possible degree of left censoring and should justify their choice of statistical methods from the broad set of available methods, including those explicitly designed for censored data.     

An Analysis of the Proportion of the U.S. Population that Ingests Soil or Other Non-Food Substances

Reliable quantitative data are lacking that document the prevalence of ingestion of soil and other “non-food” substances among U.S. children and adults. This article explores the proportion of the U.S. population that ingests substances such as soil, clay, starch, paint, or plaster. We compiled data from the National Health and Nutrition Examination Survey (NHANES) collected from years 1971–1975 (NHANES I) and 1976–1980 (NHANES II) because these particular surveys asked participants specific questions about non-food ingestion practices. We examined the prevalence of the behavior across multiple demographic variables, such as age, gender, education, and income level. Approximately 1% (NHANES II) to 2.5% (NHANES I) of the U.S. population ingests some type of non-food substance. The most notable variation across the demographic subgroups studied was the difference in estimated prevalence among young children (1 to <3 years) compared to older children and adults. Estimated prevalence was also higher among blacks compared to whites and within lower compared to higher socioeconomic groups. This analysis helps fill data gaps on the relative pattern of non-food ingestion practices on a national scale. This information provides perspective for risk assessors when evaluating exposure variables and for risk managers when weighing risk management alternatives.     

四川省喜鹊地理分布的变迁

喜鹊(Pica pica)曾是四川各地最常见的鸟类,但20世纪后期喜鹊却在四川的农耕区和城镇消失了,并持续至今。根据对1995年7月～2002年4月在四川各地搜集的野外数据分析,结合文献资料,说明喜鹊种群数量在四川于20世纪50年代后期已呈下降趋势,70年代开始出现局部消失现象,80年代是其局部灭绝的高峰期,并且消失现象从盆地扩展到周边山地和川西高原山地。进入90年代在四川已形成盆地罕见区,盆周山地、川西南山地局部分布区、川西高原广布区的分布格局。分析讨论了引起其地理分布变迁的原因,认为这是大量砍伐林木、滥用农药、人为毁巢和猎杀所造成的,而滥用剧毒农药、鼠药的影响最大。