Actual and perceived collision risk for bird strikes at Namibian airports

At Namibia’s two major airports, Hosea Kutako International and Eros (domestic), 117 bird strike collision incidents were recorded between 2006 and 2010. A risk assessment, which included a proposed risk weighting methodology, was conducted at Hosea Kutako and Eros airports, which estimated the probability of an accident/collision as well as the consequence of such a collision. The assessment included surveys of bird occurrence frequencies as well as pilot interviews. The results of the risk assessments were compared with actual bird strike incidences for each species, frequency of occurrence of birds and pilot perceptions of species risk, in order to find whether risk assessment and pilot perception are reliable measures of potential bird strike incidence. White-backed Vulture Gyps africanus and Helmeted Guineafowl Numida meleagris were the highest risk species at both airports. They were also, after Crowned Lapwing Vanellus coronatus, the species most often observed by pilots. Bird strike records showed that Crowned Lapwing and Helmeted Guineafowl were also the most frequently struck birds at both airports. The study illustrates how combining risk assessment, pilot perception and bird strike history can benefit bird strike minimisation plans at airports through the rapid identification of priority bird species.     

The origin and early evolution of birds

Birds evolved from and are phylogenetically recognized as members of the theropod dinosaurs; their first known member is the Late Jurassic Archaeopteryx, now represented by seven skeletons and a feather, and their closest known non-avian relatives are the dromaeosaurid theropods such as Deinonychus. Bird flight is widely thought to have evolved from the trees down, but Archaeopteryx and its outgroups show no obvious arboreal or tree-climbing characters, and its wing planform and wing loading do not resemble those of gliders. The ancestors of birds were bipedal, terrestrial, agile, cursorial and carnivorous or omnivorous. Apart from a perching foot and some skeletal fusions, a great many characters that are usually considered ‘avian’ (e.g. the furcula, the elongated forearm, the laterally flexing wrist and apparently feathers) evolved in non-avian theropods for reasons unrelated to birds or to flight. Soon after Archaeopteryx, avian features such as the pygostyle, fusion of the carpometacarpus, and elongated curved pedal claws with a reversed, fully descended and opposable hallux, indicate improved flying ability and arboreal habits. In the further evolution of birds, characters related to the flight apparatus phylogenetically preceded those related to the rest of the skeleton and skull. Mesozoic birds are more diverse and numerous than thought previously and the most diverse known group of Cretaceous birds, the Enantiornithes, was not even recognized until 1981. The vast majority of Mesozoic bird groups have no Tertiary records: Enantiornithes, Hesperornithiformes, Ichthyornithiformes and several other lineages disappeared by the end of the Cretaceous. By that time, a few Linnean ‘Orders’ of extant birds had appeared, but none of these taxa belongs to extant ‘families’, and it is not until the Paleocene or (in most cases) the Eocene that the majority of extant bird ‘Orders’ are known in the fossil record. There is no evidence for a major or mass extinction of birds at the end of the Cretaceous, nor for a sudden ‘bottleneck’ in diversity that fostered the early Tertiary origination of living bird ‘Orders’.     

Bird–flower interactions in the Macaronesian islands

Aims Several bird‐pollinated or ornithophilous flowers are present on the Macaronesian archipelagos, the Canary Islands and Madeira, but absent from nearby NW Africa and Europe. In Macaronesia, no specialist nectar‐feeding birds are found, but several generalist passerine bird species visit flowers for nectar. Two hypotheses attempt to explain the origin and evolution of ornithophily in the Macaronesian flora. According to ‘the island de novo hypothesis’, bird‐flowers evolved from mainland insect‐pollinated ancestors after island colonization. Alternatively, ancestors of the ornithophilous Macaronesian plant species evolved bird‐flowers before reaching the islands (‘the relict hypothesis’). In this study we first compile information of Macaronesian bird–flower interactions from the literature and our own field observations. Secondly, we discuss the two hypotheses of origin of ornithophily in the light of evidence from recent molecular plant phylogenies, palaeontology, historical biogeography of the African avifauna and flora, and present‐day ecological patterns. Location Madeira and Canary Islands. Results At least eleven endemic Macaronesian plant species from six genera have typical ornithophilous floral traits. These genera are: Canarina and Musschia (Campanulaceae), Isoplexis (Scrophulariaceae), Echium (Boraginaceae), Lotus (Fabaceae) and Lavatera (Malvaceae). These lineages have clear affinities to the Mediterranean region, except for Canarina whose closest relatives grow in East African mountains. Six generalist passerine bird species of Sylvia, Phylloscopus (Sylviidae), Serinus (Fringillidae) and Parus (Paridae) visit this flora for nectar. Main conclusion We suggest that the origin and evolution of ornithophilous traits in these plant species took place mostly in mainland areas prior to island colonization. In Canarina and Lavatera, it is well supported that ornithophily is a relict condition, which originated in mainland areas possibly in association with specialist nectar‐feeding birds. For the remaining plant species except Echium wildpretii bird floral traits probably also are a relict condition. These species may be derived from ancestors, which were visited by specialist nectar‐feeding birds during geological periods when the Mediterranean and the Ethiopian vegetation were intermingled in mainland Africa. Probably, these mainland ancestors went extinct due to severe climatic fluctuations, while their Macaronesian descendants survived in ‘refuge’ on the islands. Finally, the island de novo hypothesis may explain the evolution of a mixed bird/insect‐pollination system in the neo‐endemic red‐flowered Echium wildpretii.     

Breeding abundance of threatened raptors as estimated from occurrence data

A model derived from the negative binomial distribution (NBD) has been proposed to solve the problem of predicting abundance of species from occurrence maps. The viability of NBD was explored for predicting the breeding abundance of five threatened species of raptor: Bonelli's Eagle Hieraaetus fasciatus, Golden Eagle Aquila chrysaetos, Peregrine Falco peregrinus, Lanner Falco biarmicus and Lesser Kestrel Falco naumanni. First, the accuracy of the NBD was tested in a reference area where the species abundance and occurrence were known through intensive field surveys. Next, an estimation of regional abundance derived from NBD was made for each species. These estimates were then compared to the existing regional data for the five raptors. The spatial distributions of the species were strongly aggregated, with F. peregrinus correctly showing the most widespread area of occupancy. The NBD gave a good approximation of the breeding abundance of the raptors, but tended to overestimate real data, particularly the regional data for falcons. Difficulties in species detection, insufficient sampling effort (F. biarmicus) or data collected over long time spans when population size increased (F. naumanni) may have reduced the NBD's resolution power. The ability of the method to predict local abundances over large areas from readily available presence‐absence data, with relatively low fieldwork effort, could have considerable applications in conservation biology.     

沈阳桃仙国际机场鸟类夜间迁徙规律

在鸟类迁徙季节,夜间鸟击事故频发是机场鸟击发生的一个显著特点.了解鸟类的夜间迁徙规律对于改进夜间鸟击防范措施具有重要的指导意义.本研究综合采用网捕法和声音记录法对沈阳桃仙机场夜间鸟类迁徙物种组成和迁徙规律进行研究.结果表明: 56种鸟类(占比88.9%)具有夜间迁徙习性,且以后半夜迁徙为主;鸟类夜间迁徙具有明显的时间动态和迁徙次序,春季鸟类迁徙较为集中,迁徙高峰在5月中旬,主要鸟类由鹌鹑、红尾伯劳、栗耳鹀、黑喉石鵖、普通夜鹰、黄眉柳莺等组成,秋季迁徙较为分散,迁徙高峰出现在9月下旬至10月上旬,主要由鹌鹑、灰背鸫、红喉鹨、丘鹬、矛斑蝗莺和灰头鵐等组成.对夜间迁徙鸟类的危险等级评估发现,春季严重危险物种是鹌鹑和红尾伯劳,秋季严重危险物种是鹌鹑、纵纹腹小鸮、灰背鸫和丘鹬.分别从夜间迁徙鸟类组成、迁徙动态、时间节律和物种危险等级等角度提出了相应的鸟击防范对策,为桃仙机场鸟击防范提供参考.     

Hunting flight speeds of five southern African raptors

The flight speeds of hunting falconry birds were determined using global positioning system data loggers. Until now, the hunting flight speed of African raptors has not been directly measured. We predicted that hunting flight speeds would differ between species and that flight dynamics, such as altitude, and bird morphology, particularly wing surface area, would influence maximum and mean flight speeds. This study considered five African raptor species, which included two long-wing species, Lanner Falcon Falco biarmicus and Peregrine Falcon F. peregrinus, one short-wing species, Black Sparrowhawk Accipiter melanoleucus, and two broad-wing species, African Hawk-eagle Aquila spilogaster and Jackal Buzzard Buteo rufofuscus. Maximum and mean hunt speeds differed significantly between the long- and short-wing species. There was no difference in acceleration or deceleration rates between these species, but this could be due to small sample sizes. There was a significant positive correlation between maximum hunt speed and maximum flight height for the long-wing species. Maximum and mean flight speeds were significantly negatively correlated with wing area for all five species in this study. However, following phylogenetic correction, no significant relationship between wing area and maximum hunt speeds was found. This study presents baseline data of hunting speeds in African raptors and further highlights the importance of inter-species variation, which can provide accuracy to flight speed models and the understanding of hunting strategies.     

Bird-keeping in the Caatinga,NE Brazil

Brazil has one of the greatest bird diversities in the world, with around 1,800 species. However, many species are now threatened by illegal capture and trade that is largely driven by the culture of keeping wild birds as pets. This study documents the nature and purpose of bird capture and trade in the semi-arid Caatinga biome in northeastern Brazil, which has around 510 bird species and a population of around 25 million people. Data were obtained through observation in the homes of bird keepers and at open air markets, as well as through semi-structured and open-ended interviews and informal conversations with 52 wild bird keepers. We recorded 38 species of birds kept as pets in this study. The family with the largest number of species recorded was the Emberizidae (29%), followed by the Columbidae (16%) and the Psittacidae (16%). The most frequently kept species were: Paroaria dominicana, Aratinga cactorum, Icterus jamacaii, Sporophila albogularis, Turdus rufiventris and Cyanocompsa brissonii, which are all native to this region. Among the recorded species, only Pintassilgo (Carduelis yarrellii) is listed as an endangered species in Brazil. Of the people interviewed, 32% observed a reduction in abundance, or disappearance, of several bird species in the region. The need for measures aimed at the sustainability of wild avifauna use is therefore evident. These include law enforcement, commercial breeding and environmental education, of which the last is considered the most likely to be effective.     

湖南壶瓶山自然保护区鸟类多样性分析

湖南壶瓶山自然保护区拥有鸟类１４３种,隶属１４目３４科,其中国家一级保护动物１种,二级保护动物１６种,湖南省级保护动物２９种。该地的夏候鸟４９种,冬候鸟１４种,留鸟８０种。东洋界鸟类８５种,古北界鸟类３２种,广布性鸟类２６种。壶瓶山鸟类的多样性指数为１．８４５５,均匀性指数为０．８５５０。     

6.—DATA OF BIRDS' EGGS IN MY COLLECTION

Van Zyl, A.J, Jenkins, A.R. &; Allan, D.G. 1994. Evidence for seasonal movements by Rock Kestrels Falco tinnunculus and Lanner Falcons F. biarmicus in South Africa. Ostrich 65:111-121.

Patterns of seasonal movement by Rock Kestrels Falco tinnunculus and Lanner Falcons F. biarmicus in South Africa were determined using data from the Southern African Bird Atlas Project, road transect counts, ringing recoveries and other sources. Both species were found to be partial, facultative migrants, and Lanner Falcon movements involved mostly immature birds. Rock Kestrels were found to concentrate in the southwest of the country in the breeding season, and to move north and east in the non-breeding season. Lanner Falcons concentrated in the east of the country during the breeding season, and moved into the west in the non-breeding season. The movement by both species into the arid northwest of the country is probably associated with dramatic increases in prey abundance, in turn associated with summer rah events. Lanner Falcon movement into the southern Cape apparently coincides with cereal farming practices, affecting the availability of prey (granivorous birds and rodents). Rock Kestrel movement into the east of the aunt is probably to exploit increases in insect abundance mated with summer rain. The pattern of Rock Kestrel movements suggests that it does not compete for food with the Lesser Kestrel F. naumanni. a Palearctic migrant to the east of the country.     

微山湖鸟类多样性特征及其影响因子

2010年10月至2011年9月期间,使用样线法对微山湖鸟类多样性进行研究.共发现鸟类132种,隶属13目39科,其中留鸟39种,夏候鸟33种,冬候鸟14种,旅鸟46种,分别占全部种类的29.6％、25.0％、10.6％和34.85％;国家二级保护鸟类有12种,省级重点保护鸟类16种,另外50种和16种鸟类分别列入中日、中澳候鸟保护协定.灰鹤、乌雕、沙鵖和白顶鵖4种鸟类在南四湖首次记录.根据微山湖的地理和植被状况,将研究区域划分为水域、次生林、农田和居民区4生境,不同生境中鸟类群落的Shannon-Wiener指数高低为沼泽水域＞次生林＞农田＞居民区,Pielou指数高低为沼泽水域＞农田＞次生林＞居民区.次生林和农田鸟类群落的相似性指数最高,沼泽水域与居民区的相似性最低.春季末期鸟类多样性指数和均匀性指数最高,秋季末期最低.冬季鸟类种类最多、密度最大,春初鸟类种类最少、密度最小.距居民区的距离、距公路的距离、植被盖度、人工池塘数目、水面积比例和深水面积比例等对鸟类多样性影响显著.     

样线法和网捕法在机场鸟情调查中的应用比较

鸟击事件主要发生在机场范围内,对机场周边生境的鸟类组成进行调查,是制定鸟击防范对策的重要前提。国内多数机场已经开展了相关的鸟类组成调查,但是选用的调查方法却存在较大差异。以样线法和网捕法两种常用的调查方法对沈阳桃仙国际机场周边的迁徙期鸟类进行了研究,旨在比较两种调查方法在机场鸟类群落组成调查中的效果及调查的鸟类群落组成差异。结果表明：两种方法均适合机场鸟类调研,共记录到鸟类97种,网捕法记录的鸟类种数(83种vs. 57种)高于样线法,网捕法单独记录的鸟类种数(40种vs. 14种)也高于样线法。尽管两种方法每期(半个月)调查的物种数和目的数量无明显差别,但随调查强度(如调查次数)增加,网捕法累计记录到的鸟类种类明显高于样线法,且较晚达到渐近线。另外,两种方法调查记录的鸟类群落组成也具有显著的差别,如网捕法记录到较多鹌鹑和鸮形目等夜间迁徙或活动鸟类,而样线法可记录到鹭科和雁鸭类水鸟等。这说明两种调研方法在鸟类调查中有较好的互补性。因此,本研究认为机场鸟情调研时应该根据鸟情特点,选择合适的鸟类调研方法,综合采用多种调研方法可更有利于获得科学的鸟情信息。     

Species of street tree is important for southern hemisphere bird trophic guilds

Abstract Urban environments are highly modified with unique assemblages of bird species. Much of the research on urban bird assemblages comes from the northern hemisphere. Southern hemisphere bird assemblages differ from northern hemisphere assemblages in that they contain a large proportion of nectarivores. In this study we focus on bird use of street trees in Australia. We investigate the relative influence of tree species (plane tree, Platanus x acerifolia; red gums, Eucalyptus camaldulensis; jacaranda, Jacaranda mimosifolia; bottlebrush, Callistemon citrinus), season and the environment surrounding street trees, on the abundance and species richness of birds in Adelaide, South Australia. Our study considers birds in terms of granivore, nectarivore and insectivore trophic guilds. Nectarivores accounted for the greatest proportion of observations, in terms of abundance, in each of the tree species investigated. Species of street tree was a significant influence on bird use of the trees for all birds and each dietary guild. Red gums were used more than the other tree species by nectarivores, while plane trees were used more than the other trees by insectivores. Use of the tree species by granivores varied with the season. The measures of the environment surrounding street trees were largely unimportant with the exception of traffic for nectarivores in some cases. Urban avifauna use street trees and the species of tree will strongly influence its use by birds. However, the pattern of use of street tree species varied at different times of year and differed between different trophic guilds of birds. The dominance of nectarivores in the southern avifauna will likely produce different patterns of urban environment use to northern hemisphere avifaunas.     

Host range and community structure of avian nest parasites in the genus Philornis (Diptera: Muscidae) on the island of Trinidad

Parasite host range can be influenced by physiological, behavioral, and ecological factors. Combining data sets on host–parasite associations with phylogenetic information of the hosts and the parasites involved can generate evolutionary hypotheses about the selective forces shaping host range. Here, we analyzed associations between the nest‐parasitic flies in the genus Philornis and their host birds on Trinidad. Four of ten Philornis species were only reared from one species of bird. Of the parasite species with more than one host bird species, P. falsificus was the least specific and P. deceptivus the most specific attacking only Passeriformes. Philornis flies in Trinidad thus include both specialists and generalists, with varying degrees of specificity within the generalists. We used three quantities to more formally compare the host range of Philornis flies: the number of bird species attacked by each species of Philornis, a phylogenetically informed host specificity index (Poulin and Mouillot's S_TD), and a branch length‐based S_TD. We then assessed the phylogenetic signal of these measures of host range for 29 bird species. None of these measures showed significant phylogenetic signal, suggesting that clades of Philornis did not differ significantly in their ability to exploit hosts. We also calculated two quantities of parasite species load for the birds – the parasite species richness, and a variant of the S_TD index based on nodes rather than on taxonomic levels – and assessed the signal of these measures on the bird phylogeny. We did not find significant phylogenetic signal for the parasite species load or the node‐based S_TD index. Finally, we calculated the parasite associations for all bird pairs using the Jaccard index and regressed these similarity values against the number of nodes in the phylogeny separating bird pairs. This analysis showed that Philornis on Trinidad tend to feed on closely related bird species more often than expected by chance.     

Habitat utilisation and nesting behaviour of two sympatric weavers in Mbalmayo District,Cameroon

Avian ecology and behaviour data provides crucial information for bird conservation and management, but are still missing for many species, particularly in developing countries. This study examines habitat utilisation, nesting behaviour, anthropogenic disturbances and impacts on agricultural crops of Village Weaver Ploceus cucullatus and Vieillot’s Black Weaver Ploceus nigerrimus in Mbalmayo District, Cameroon. Abundance was estimated by nest counts and point counts of birds at 40 previously located colonies, where also tree metrics and anthropogenic disturbances were measured. In total, more than 1 700 birds of the two species were estimated within a 9 km2 study area, divided into two blocks and five different habitat types. Village Weavers were generally more abundant, especially in the urban habitat, whereas Vieillot’s Black Weavers were most numerous in the rural habitat. Among the tree species used for nesting, mango Mangifera indica and African border tree Newbouldia laevis had the highest nest counts, which also was positively related to canopy cover diameter. Traffic noise disturbance was associated with lower bird and nest counts, whereas the opposite was observed on farming disturbance. The relative impacts on agricultural crops were estimated for African oil palm Elaeis guineensis (38%), maize Zea mays (36%), Musa spp. (18%) and Mangifera indica (8%). The implications for long-term coexistence between farmland birds and humans are discussed, and the challenge is to minimise both kinds of bird–human interactions, i.e. anthropogenic disturbances and agricultural crop damage.     

张掖国家湿地公园优势鸟类种群生态位研究

鸟类时空格局影响下鸟类种群生态位的变化是认识鸟类环境适应机制的理论基础。在张掖国家湿地公园保育区,采用样带法研究了冬春季节5种优势鸟类种群生态位宽度和生态位重叠的时间异质性。结果表明:随着月份的更替,5种优势鸟类种群的生态位宽度呈现出先增大后减小的变化趋势,赤麻鸭(Tadornaferruginea)、绿头鸭(Anasplatyrhynchos)、麻雀(Passer montanus)、白骨顶鸡(Fulicaatra)的最高值出现在1月分别为1.601、1.415、1.627、1.771,大白鹭(Ardea alba)的最高值出现在3月为0.556;不同月份间鸟类优势种群生态位重叠存在差异,3月、11月生态位的重叠值最大,1月份最小;优势鸟类种群的生态位宽度和重叠在时间尺度上表现出"此消彼长"的关系。湿地公园时间尺度上的鸟类生态位宽度和重叠的差异与湿地食物资源及隐蔽条件、鸟类群体迁徙规律、鸟类种间的竞争密切相关,反应了湿地鸟类适应生境变化的可塑性机制。     

广东顺德生态乐园夏季鸟类资源和保护

报道了顺德生态乐园夏季鸟类资源的调查 ,记录了该乐园鸟类有 55种 ,隶属 6目2 0科 ,其中属国家二级重点保护鸟类 9种。对鸟类的生态作用、种类和组成作了讨论 ,并提出了保护鸟类的重要性和保护措施。     

Aeroecology meets aviation safety: early warning systems in Europe and the Middle East prevent collisions between birds and aircraft

The aerosphere is utilized by billions of birds, moving for different reasons and from short to great distances spanning tens of thousands of kilometres. The aerosphere, however, is also utilized by aviation which leads to increasing conflicts in and around airfields as well as en‐route. Collisions between birds and aircraft cost billions of euros annually and, in some cases, result in the loss of human lives. Simultaneously, aviation has diverse negative impacts on wildlife. During avian migration, due to the sheer numbers of birds in the air, the risk of bird strikes becomes particularly acute for low‐flying aircraft, especially during military training flights. Over the last few decades, air forces across Europe and the Middle East have been developing solutions that integrate ecological research and aviation policy to reduce mutual negative interactions between birds and aircraft. In this paper we 1) provide a brief overview of the systems currently used in military aviation to monitor bird migration movements in the aerosphere, 2) provide a brief overview of the impact of bird strikes on military low‐level operations, and 3) estimate the effectiveness of migration monitoring systems in bird strike avoidance. We compare systems from the Netherlands, Belgium, Germany, Poland and Israel, which are all areas that Palearctic migrants cross twice a year in huge numbers. We show that the en‐route bird strikes have decreased considerably in countries where avoidance systems have been implemented, and that consequently bird strikes are on average 45% less frequent in countries with implemented avoidance systems in place. We conclude by showing the roles of operational weather radar networks, forecast models and international and interdisciplinary collaboration to create safer skies for aviation and birds.     

千岛湖陆桥岛屿鸟类集团对栖息地片段化的敏感性及其季节变化

为探究千岛湖陆桥岛屿不同鸟类集团对栖息地片段化敏感性的差异和季节变化,于2009年4月—2012年1月鸟类繁殖季(4、5、6月)和冬季(11、12、1月)对千岛湖41个陆桥岛屿鸟类集团进行了研究。结果表明,冬季杂食鸟对片段化敏感性高于食虫鸟,繁殖季时二者无显著差异,繁殖季和冬季时下层鸟对片段化敏感性均高于林冠鸟,冬季留鸟对片段化敏感性高于候鸟,繁殖季则无显著差异。杂食鸟和留鸟对片段化敏感性存在季节差异,而食虫鸟、林冠鸟、下层鸟和候鸟对片段化敏感性均无季节差异。不同鸟类集团对栖息地片段化敏感性的差异和季节变化规律,有助于人们在栖息地管理和保护区设计时采取更有针对性的鸟类保护措施。     

三峡重庆库区不同鸟类群落的物种组成及多样性研究

1996～1997年,对三峡工程重庆库区的鸟类群落物种组成和种群数量进行了调查,共调查记录库区鸟类15目48科226种,数量18929只。用鸟类数量级划分、Sorensen相似性指数、Shannon-Wiener指数和Pielou指数分析库区各种生境鸟类群落物组成和物种多样性结果表明：1）库区天然林、人工林、灌草丛和水域生境中鸟类群落的组成与农田生境具有较高的相似性,尤以人工林和农田的相似性最高;2）库区人工林生境鸟类群落物种多样性最高;3）库区由于长期以来人类活动的影响,生境日趋单一,已逐渐形成一种以农田灌丛鸟类为主的鸟类生态系统。     

长江师范学院校园夏季鸟类群落与多样性分析

2008年3～7月采用样线法对长江师范学院李渡校园鸟类组成和种群数量进行了调查,共记录鸟类6目21科28种,数量1633只,物种多样性指数为3．9204,均匀性指数为1．1765,其中国家“三有”名录鸟类25种,CITES名录鸟类1种。鸟类区系以东洋界成分为主。对不同生境鸟类多样性的分析结果表明：（1）乔灌林鸟类多样性指数和均匀性指数最高,水域鸟类多样性指数最低,建筑区均匀性指数最低;（2）乔灌林与竹林的相似性指数最高,竹林与水域的相似性最低。