Spatio-temporal use of the urban habitat by feral pigeons (Columba livia )

Feral pigeons are descendants of wild rock pigeons that have adapted to the urban habitat. They have partially conserved the foraging behaviour of their wild ancestors (flights to agricultural areas) but have also developed new habits. Previous studies on the foraging strategies of feral pigeons have given various results, e.g. maximum distances reached by the pigeons (measured in a straight line from the resting places) differed between 0.3–0.5 km and 18–25 km. This study focuses on the spatio-temporal activity of feral pigeons in the urban habitat. We equipped 80 free-living feral pigeons from Basel, Switzerland with GPS receivers. We found three different foraging strategies for pigeons in Basel: (1) in the streets, squares and parks near the home loft, (2) in agricultural areas surrounding the city, (3) on docks and railway lines in harbours. The maximum distance reached by a pigeon was 5.29 km. More than 32% of the pigeons remained within 0.3 km of the home lofts and only 7.5% flew distances of more than 2 km. Females covered significantly longer distances than males, preferring to fly to more abundant and predictable food sources. Temporal activity patterns showed to be influenced by sex, breeding state and season. In contrast to wild rock pigeons and to feral pigeons in other cities, pigeons in Basel showed a clear bimodal activity pattern for breeding birds only. The differences between our results and those of other studies seem to be partly method-dependent, as the GPS-technique allows to record the pigeons’ localisations continuously in contrast to other methods. Other differences might be due to different kinds of food supply in the various cities. Our study shows that feral pigeons have individual foraging strategies and are flexible enough to adapt to different urban environments.Electronic supplementary material Supplementary material is available for this article at     

Loft features influence the processing of navigational information by pigeons

The present study evaluates the impact of lofts on the development of the navigational system of pigeons. A series of results obtained between 2000 and 2004 were analyzed. The H-loft was placed 10 m above the ground, with a ring format and seven windows all around it as well as three external aviaries that allowed birds to have a wide view of the outdoors and of the sky and knowledge of the wind dynamics. The L-loft was placed at ground level, with a single window transformed into an external aviary. The L-loft was protected from the wind by surrounding trees, reducing the ability of the pigeons to access the wind dynamics and also restricting their access to information regarding the outside area and the sky. In a preliminary analysis, we found the parameter of “vanishing time” to differ significantly between lofts in two of the five age classes. A thorough analysis of this parameter throughout the ontogenetic development of the birds demonstrated a pronounced improvement in the information-processing system with age, with adults vanishing quicker than younger birds, although an impairment of development occurred during the third month of age, perhaps due to a reorganization of the system. This result was obtained when the effect of lofts was considered in the different age classes. Results suggest that loft features are an important factor in the ability of the young pigeons to exploit navigational cues.     

A field experiment characterizing variable detection rates during plant surveys

Surveys aimed at finding threatened and invasive species can be challenging due to individual rarity and low and variable individual detection rates. Detection rate in plant surveys typically varies due to differences among observers, among the individual plants being surveyed (targets), and across background environments. Interactions among these 3 components may occur but are rarely estimated due to limited replication and control during data collection. We conducted an experiment to investigate sources of variation in detection of 2 Pilosella species that are invasive and sparsely distributed in the Alpine National Park, Australia. These species are superficially similar in appearance to other yellow-flowered plants occurring in this landscape. We controlled the presence and color of flowers on target Pilosella plants and controlled their placement in plots, which were selected for their variation in cover of non-target yellow flowers and dominant vegetation type. Observers mimicked Pilosella surveys in the plots and reported 1 categorical and 4 quantitative indicators of their survey experience level. We applied survival analysis to detection data to model the influence of both controlled and uncontrolled variables on detection rate. Orange- and yellow-flowering Pilosella in grass- and heath-dominated vegetation were detected at a higher rate than nonflowering Pilosella. However, this detection gain diminished as the cover of other co-occurring yellow-flowering species increased. Recent experience with Pilosella surveys improved detection rate. Detection experiments are a direct and accessible means of understanding detection processes and interpreting survey data for threatened and invasive species. Our detection findings have been used for survey planning and can inform progress toward eradication. Interaction of target and background characteristics determined detection rate, which enhanced predictions in the Pilosella eradication program and demonstrated the difficulty of transferring detection findings into untested environments.     

低磷胁迫下木豆利用磷的基因型差异及其机制

以木豆[Cajanus Cajan(L.)Millsp]MD2、MD5、MD7为材料,采用水培试验方法研究了木豆对磷的吸收、利用的基因型差异及其机理。结果表明:低磷(P1 μmol·L-1)胁迫下,木豆对磷素的吸收和利用效率存在明显的基因型差异,其中MD2、MD7属于磷素吸收、利用效率较强的基因型,而MD5为磷素效率较低的基因型。低磷培养16d后,磷高效的基因型的根/冠比显著增加,根分泌的酸性磷酸酶(APA)活性较高,说明木豆对磷素的吸收效率与植株的根冠比及根分泌的酸性磷酸酶活性有关。在低磷胁迫下,虽然MD7、MD2的含磷量较低,但是磷素利用效率和根尖中APA活性较高,说明根中高APA活性是磷利用效率高的重要原因之一。     

Ecology of reproduction of the red king crab

Conditions for reproduction of the red king crab Paralithodes camtschatica (Tilesius) on scallop plantations in Primorye have been studied. It has been found that the settling of larvae and the growth of juveniles to the size sufficient for their survival take place only in the cleanest water areas of Peter the Great Bay. Solar activity (expressed as the Wolfer number) is one of the most important abiotic factors affecting P. camtschatica reproduction. The population dynamics of juvenile crabs are characterized by fluctuations with two-year and five-year cycles.     

不同木豆品种耐铝性的基因型差异及其机理研究

以6个品种的木豆为材料，探讨了木豆品种间耐铝性的基因型差异及其机制。铝对根伸长的抑制大小及苏木精对根尖的染色模式的研究结果表明，不同品种木豆的耐铝性基因型差异明显。在铝胁迫条件下，去除根尖吸附的粘胶，耐铝的基因型MD2和敏感的基因型MD5根的伸长率均减少，而根尖被苏木精染色程度加深；去除粘胶对MD2的影响大于MD5，说明粘胶对根尖的保护是木豆抵御铝毒的一个重要机制。虽然铝胁迫可诱导木豆根系分泌柠檬酸和苹果酸，但根系苹果酸的分泌量在MD2和MD间无显著差异，MD2柠檬酸的分泌量甚至低于MD5。     

Neurobiology of the homing pigeon—a review

Homing pigeons are well known as good homers, and the knowledge of principal parameters determining their homing behaviour and the neurological basis for this have been elucidated in the last decades. Several orientation mechanisms and parameters—sun compass, earth’s magnetic field, olfactory cues, visual cues—are known to be involved in homing behaviour, whereas there are still controversial discussions about their detailed function and their importance. This paper attempts to review and summarise the present knowledge about pigeon homing by describing the known orientation mechanisms and factors, including their pros and cons. Additionally, behavioural features like motivation, experience, and track preferences are discussed. All behaviour has its origin in the brain and the neuronal basis of homing and the neuroanatomical particularities of homing pigeons are a main topic of this review. Homing pigeons have larger brains in comparison to other non-homing pigeon breeds and particularly show increased size of the hippocampus. This underlines our hypothesis that there is a relationship between hippocampus size and spatial ability. The role of the hippocampus in homing and its plasticity in response to navigational experience are discussed in support of this hypothesis.     

Avermectin induced inflammation damage in king pigeon brain

To determine the effect of Avermectin (AVM) on inflammation damage in king pigeon brain, eighty two-month-old American king pigeons were randomly divided into four groups, and were fed with either commercial diet or AVM-supplemented diet containing 20 mg kg⁻¹ diet, 40 mg kg⁻¹ diet, and 60 mg kg⁻¹ diet AVM for 30, 60 and 90 d, respectively. Then, the expression level of inflammatory factors (iNOS, PTGEs, NF-κB), histological damage, and ultra-structural damage were examined. It showed that AVM caused higher expressions (P < 0.05) of iNOS, PTGEs, NF-κB with disorganized histological and ultra-structural structures in cerebrum, cerebellum, and optic lobe. Meanwhile, inflammatory and histopathological damage were induced by AVM in king pigeon brains. In addition, the main targeted organelle in nervous system was mitochondria, which indicated that mitochondria may be relevant to the process of inflammation induced by AVM. To our best knowledge, this is the first report to study the toxic effect of AVM on inflammatory damage in king pigeon. Thus, the information presented in this study is believed to be helpful in supplementing data for further AVM toxicity study.     

浅谈商品包装设计与包装策略

在市场经济的今天，商品包装显得尤为重要。包装是企业形象中不可缺少的一个重要组成部分，是体现传播企业形象的一个重要媒介物。本文正是从这个角度出发，给出了商品包装设计应遵循的原则和如何正确实施包装策略。