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1.
Trans‐equatorial avian migrants tend to breed, moult and migrate – the main energy‐requiring events in their lifecycle – at different times. Little is known about the relationship between wing moult and pre‐migratory fuelling in waders on their non‐breeding grounds, where time is less constrained than during their brief high‐latitude breeding season. We determined age‐related strategies of Wood Sandpipers Tringa glareola to balance the energetic demands of primary moult against pre‐migratory fuelling in southern Africa by analysing body mass and primary moult at first capture of 1721 birds mist‐netted in 1972–96 at waterbodies in Zimbabwe. Adults moulted all their primaries in August–December, but immatures underwent a supplemental moult of varying numbers of outer primaries in December–April, close to departure. We used locally weighted linear regression to estimate trends in Wood Sandpiper body mass from 1 July to 1 May. They maintained low mass from arrival in July–September to February–early March. Adults fuelled from 10 February to 1 May at a mean rate of 0.25 g/day (sd = 0.16). Most adults (98%) began fuelling 10–75 days after completing primary moult. Immatures fuelled from 4 March to 13 April at 0.24 g/day (sd = 0.14). They used varying strategies depending on their condition: a brief gap between moult and fuelling; an overlap of these processes near departure, leading to slower fuelling; or skipping fuelling altogether and staying in southern Africa for a ‘gap year’. Immatures moulting three or five outer primaries fuelled more slowly than post‐moult birds. Immatures moulting four outer primaries started fuelling 3 weeks later but at a higher rate than did post‐moult birds of this group. In post‐moult immatures, the later they ended moult, the later and faster they fuelled. The heaviest adults and immatures using all moult patterns accumulated fuel loads of c. 50% of lean body mass, and could potentially cross 2397–4490 km to reach the Great Rift Valley in one non‐stop flight. Immatures were more flexible in the timing and extent of moult and in the timing and rate of fuelling than adults. This flexibility enables inexperienced Wood Sandpipers to cope with inter‐annual differences in feeding conditions at Africa's ephemeral inland waterbodies. 相似文献
2.
《Ostrich》2013,84(3):231-241
Inferred hybrid Chorister Robin-Chat Cossypha dichroa and Red-capped Robin-Chat C. natalensis have previously only been recorded from the Eastern Cape province, South Africa. We extend the occurrence of inferred hybrids with ringed and photographed examples from KwaZulu-Natal and Limpopo provinces. Sympatry at a fine scale was investigated at Vernon Crookes Nature Reserve, KwaZulu-Natal, using observational data over 30 years (1978–2008) and intensive mist-netting during two field-trips in June and October 2010. Both robin-chat species were found throughout the year and occurred in the same forest patches. Inferred hybrids are known from five different forest patches in Vernon Crookes, three with photographic evidence. During winter an increase in Chorister Robin-Chat numbers was detectable both from mist-netting and checklist data. An increase of Red-capped Robin-Chats was observed from mist-netting and more equivocally from checklist data in spring. Red-capped and Chorister Robin-Chats are sympatric along the eastern escarpment of South Africa, with co-occurrence in 96 quarter degree squares from Southern African Bird Atlas Project 1 data. During the breeding season, co-occurrence was recorded in 62 quarter degree squares and in nine grid-cells evidence of breeding by both species is available. Hybridisation may be more common along the extensive area of sympatry than currently realised. 相似文献
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Hans‐Jürgen Eilts Nele Feuerbach Philip D. Round Oleg Bourski John Allcock Paul Leader Batmunkh Davaasuren Tuvshinjargal Erdenechimeg Jong‐Gil Park Wieland Heim 《Ecology and evolution》2021,11(1):11-21
Molt strategies have received relatively little attention in current ornithology, and knowledge concerning the evolution, variability and extent of molt is sparse in many bird species. This is especially true for East Asian Locustella species where assumptions on molt patterns are based on incomplete information. We provide evidence indicating a complex postbreeding molt strategy and variable molt extent among the Pallas's Grasshopper Warbler Locustella certhiola, based on data from six ringing sites situated along its flyway from the breeding grounds to the wintering areas. Detailed study revealed for the first time that in most individuals wing feather molt proceeds from the center both toward the body and the wing‐tip, a molt pattern known as divergent molt (which is rare among Palearctic passerines). In the Russian Far East, where both breeding birds and passage migrants occur, a third of the adult birds were molting in late summer. In Central Siberia, at the northwestern limit of its distribution, adult individuals commenced their primary molt partly divergently and partly with unknown sequence. During migration in Mongolia, only descendantly (i.e., from the body toward the wing‐tip) molting birds were observed, while further south in Korea, Hong Kong, and Thailand the proportion of potential eccentric and divergent feather renewal was not identifiable since the renewed feathers were already fully grown as expected. We found an increase in the mean number of molted primaries during the progress of the autumn migration. Moderate body mass levels and low‐fat and muscle scores were observed in molting adult birds, without any remarkable increase in the later season. According to optimality models, we suggest that an extremely short season of high food abundance in tall grass habitats and a largely overland route allow autumn migration with low fuel loads combined with molt migration in at least a part of the population. This study highlights the importance of further studying molt strategy as well as stopover behavior decisions and the trade‐offs among migratory birds that are now facing a panoply of anthropogenic threats along their flyways. 相似文献
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INÊS CATRY MARIA P. DIAS TERESA CATRY VSEVOLOD AFANASYEV JAMES FOX ALDINA M.A. FRANCO WILLIAM J. SUTHERLAND 《Ibis》2011,153(1):154-164
The population decline of the Lesser Kestrel Falco naumanni has been the subject of studies across its Western Palaearctic breeding range, but little is known about its use of pre‐migratory areas or African wintering quarters. We used geolocators to describe the temporal and spatial patterns of Portuguese Lesser Kestrel migration and wintering behaviour. Data on the complete migration were obtained from four individuals and another three provided further information. Prior to southward migration, Lesser Kestrels showed two different behaviours: northward‐orientated movements to Spain and movements in the proximity of the breeding area. Autumn migration took place mostly in late September; spring departures occurred mainly in the first half of February. Wintering grounds included Senegal, Mauritania and Mali, with individuals overlapping considerably in Senegal. Movements registered within the wintering grounds suggest itinerant behaviour in relation to local flushes of prey. During spring migration, birds crossed the Sahara Desert through Mauritania, Western Sahara and Morocco before passing over the Mediterranean to reach Portugal. Autumn migration lasted 4.8 ± 1.1 days, and spring migration lasted 4.1 ± 0.3 days. The mean daily flight range varied between approximately 300 and 850 km for an entire journey of around 2500 km. Effective protection of roosting sites in both pre‐migratory and wintering areas and maintaining grasshopper populations in Sahelian wintering quarters appear crucial in preserving this threatened migratory raptor across its African–Eurasian flyway. There was no evidence of any deleterious effects of fitting birds with loggers. 相似文献
5.
澳大利亚迁飞性害虫的预测与治理 总被引：2，自引：0，他引：2
DavidHunter TedDeveson 《Entomologia Sinica》2002,9(4):13-25
Decision Support System(DSS)是澳大利亚疫蝗治理委员会用于治理几种重要迁飞性害虫的决策支持系统。该系统以地理信息系统（GIS）为平台,将天气资料和害虫栖境条件与害虫的迁飞,发育及分布数据进行整合以发布预测并辅助防治决策。该系统呈模块化结构,其模块的数量和性质可根据目标害虫治理所需的具体资料方便地调整。 相似文献
6.
Abstract The Decision Support System (DSS) used by the Australian Plague Locust Commission for management of several important migratory insect pests in Australia is described. The DSS is based on a Geographic Information System that integrates data on weather and habitat condition with the migration, development and distribution of the pest to prepare forecasts and aid decisions for control. The GIS is module based with the number and nature of the modules easily modified depending on the detail of data required to manage the pest concerned. 相似文献
7.
Catriona A. Morrison Robert A. Robinson Jacquie A. Clark Jennifer A. Gill 《Diversity & distributions》2010,16(4):620-627
Aim Over the past three decades, evidence has been growing that many Afro‐Palaearctic migratory bird populations have suffered sustained and severe declines. As causes of these declines exist across both the breeding and non‐breeding season, identifying potential drivers of population change is complex. In order to explore the roles of changes in regional and local environmental conditions on population change, we examine spatial and temporal variation in population trajectories of one of Europe’s most abundant Afro‐Palaearctic summer migrants, the willow warbler, Phylloscopus trochilus. Location Britain and Ireland. Methods We use national survey data from Britain and Ireland (BBS: BTO/RSPB/JNCC Breeding Bird Survey and CBS: BWI/NPWS/Heritage Council Countryside Breeding Survey) from 1994 to 2006 to model the spatial and temporal variation in willow warbler population trends. Results Across Britain and Ireland, population trends follow a gradient from sharp declines in the south and east of England to shallow declines and/or slight increases in parts of north and west England, across Scotland and Ireland. Decreasing the spatial scale of analysis reveals variation in both the rate and spatial extent of population change within central England and the majority of Scotland. The rates of population change also vary temporally; declines in the south of England are shallower now than at the start of the time series, whereas populations further north in Britain have undergone periods of increase and decline. Main conclusion These patterns suggest that regional‐scale drivers, such as changing climatic conditions, and local‐scale processes, such as habitat change, are interacting to produce spatially variable population trends. We discuss the potential mechanisms underlying these interactions and the challenges in addressing such changes at scales relevant to migratory species. 相似文献
8.
Satoshi Fukuhara Hiroshi Nishimasu Luc Bonnefond Naoki Matsumoto Ryuichiro Ishitani Osamu Nureki 《Acta Crystallographica. Section F, Structural Biology Communications》2012,68(11):1346-1350
PIWI‐interacting RNAs (piRNAs) bind PIWI proteins and silence transposons to maintain the genomic integrity of germ cells. Zucchini (Zuc), a phospholipase D superfamily member, is conserved among animals and is implicated in piRNA biogenesis. However, the underlying mechanism by which Zuc participates in piRNA biogenesis remains elusive. Drosophila melanogaster Zuc (DmZuc) was expressed in Escherichia coli, purified and crystallized. X‐ray diffraction data were collected to 1.75 Å resolution. The crystal belonged to space group P21, with unit‐cell parameters a = 55.0, b = 71.2, c = 56.3 Å, β = 107.9°. 相似文献
9.
Abstract Yallalie is a probable meteor impact crater and in the Upper Pliocene contained a substantial lake. Two Mid‐Pliocene finely laminated sediment records from Palaeolake Yallalie, from about 3 million years ago, provide evidence of fire and fire frequency in the sclerophyll woodland and heaths of south‐western Australia in the absence of humans. Fine charcoal was observed in all samples examined, and was deposited at a rate of about 0.3–0.8 cm2 cm?2 year?1 in Palaeolake Yallalie. This evidence suggests the occurrence of annual fires occurring every year in the slightly warmer and wetter climate compared with today. The near coastal western location and the prevailing westerly winds probably carry charcoal from the near region or lake catchment scale. The data indicate that local fires occurred at a variety of time intervals between 3 and 13 years, with a typical average of 6–10 years. The results are comparable with those of Atahan et al. (2004) for the same site but from a period of about 200 000 years later in the Mid‐Pliocene. Thus, the records which differ in age by some hundreds of thousands of years have all recorded fire frequencies that are longer than for the historical period and this may have important implications for the long‐term survival of the integrity of the high biodiversity plant communities of the region. 相似文献
10.
Eveling A. Tavera David B. Lank Patricia M. González 《Journal of Field Ornithology》2016,87(3):293-308
Migration distances of shorebird species correlate with life history strategies. To assess age‐specific migratory preparation and adult wing‐molt strategies, we studied Western Sandpipers (Calidris mauri) and Semipalmated Sandpipers (C. pusilla) with different migration routes at the Paracas National Reserve in Perú, one of the most austral non‐breeding areas for these sandpipers, from 2012 to 2015. Western Sandpipers breed near the Bering Sea, ~11,000 km from Paracas. Semipalmated Sandpiper populations at Paracas are a mixture of short‐billed birds from western Arctic breeding sites, plus long‐billed birds from eastern sites, ~8000 km distant. Adults of both species arrive in October with primary feathers already partially renewed so wing molt starts at sites further north. Semipalmated Sandpipers with longer bills completed wing molt later than shorter billed birds. Adults of both species prepared for migration in February and March. No juvenile Western Sandpipers prepared for migration, confirming the “slow” over‐summering life history strategy of more southerly non‐breeding populations. Juvenile Semipalmated Sandpipers showed bimodality in strategies. Most showed no migratory preparation, but, during three non‐breeding periods, from 27% to 31% fattened, molted, and partially replaced outer primaries during the pre‐migratory period. Juveniles with longer culmens were heavier and tended to have more alternate plumage. Juveniles that were partially molting primaries had longer culmens and more alternate plumage. Juvenile Semipalmated Sandpipers from eastern‐breeding populations thus have a higher propensity for a fast life history strategy, and western birds a slow one, at this non‐breeding site in Peru. Western‐breeding Semipalmated Sandpiper populations thus resemble Western Sandpipers, suggesting a common, possibly distance‐related, effect on life history strategy. 相似文献
11.
Recent behavioral observations have indicated that bats can sense the Earth's magnetic field. To unravel the magnetoreception mechanism, the present study has utilized magnetic measurements on three migratory species (Miniopterus fuliginosus, Chaerephon plicata, and Nyctalus plancyi) and three non‐migratory species (Hipposideros armiger, Myotis ricketti, and Rhinolophus ferrumequinum). Room temperature isothermal remanent magnetization acquisition and alternating‐field demagnetization showed that the bats' heads contain soft magnetic particles. Statistical analyses indicated that the saturation isothermal remanent magnetization of brains (SIRM1T_brain) of migratory species is higher than those of non‐migratory species. Furthermore, the SIRM1T_brain of migratory bats is greater than their SIRM1T_skull. Low‐temperature magnetic measurements suggested that the magnetic particles are likely magnetite (Fe3O4). This new evidence supports the assumption that some bats use magnetite particles for sensing and orientation in the Earth's magnetic field. Bioelectromagnetics 31:499–503, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
12.
Leah S. Beesley Savannah Killerby-Smith Daniel C. Gwinn Bradley J. Pusey Michael M. Douglas Peter A. Novak Thiaggo C. Tayer Chris S. Keogh Mark J. Kennard Caroline A. Canham Samantha A. Setterfield 《Freshwater Biology》2023,68(1):61-76
- Water development threatens rivers and their biodiversity. Amphidromous shrimp are particularly vulnerable as they require migration between freshwater and estuaries to complete their life cycle. The Fitzroy River is a large tropical intermittent river undergoing water development that is home to the amphidromous shrimp Macrobrachium spinipes (cherabin), yet little is known about its habitat use and flow-ecology making it difficult to inform sustainable water-take.
- We investigated habitat associations, distributional patterns suggestive of amphidromy, and the influence of water availability by sampling main channel and floodplain pools along a 350-km river length during 2 contrasting flow years. Applying a size-specific abundance model, we estimated abundance per size class, site, and year. We then predicted abundance at the landscape scale with remotely sensed water to reveal the impact of water availability on the meta-population.
- Our model revealed that juveniles were in greatest abundance in downstream main channel pools, whereas adults were in greatest abundance in upstream floodplain pools. Abundance varied by year with lower numbers predicted in the low-flow year. Longitudinal and habitat patterns remained when our pool-level results were scaled to the landscape, and the positive relationship of abundance to wet-season flow was strengthened. The predominance of smaller cherabin in the lower reaches of the river provides indirect support for an estuarine nursery and amphidromous life history; however, small individuals observed in landlocked pools, during late dry season suggests possible within-river recruitment.
- The importance of water development policies that protect wet-season flow and passage along the Fitzroy River is supported by this work. These types of policies are likely to be important for this and other amphidromous shrimp species across Australia, Southeast Asia and further afield. Further research detailing the species life history and describing flow–recruitment relationships will be important contributions to understanding this important taxonomic group and refining policies for current and future water resource development.
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D. T. Tyler Flockhart 《Journal of Field Ornithology》2010,81(4):373-382
ABSTRACT On the breeding grounds, migratory birds have limited time to breed and molt before autumn migration. However, few studies of long‐distance migrants have examined the phenology of these events to determine what life‐history trade‐offs might result if these activities overlap. From 2000 to 2007, I used banding data to determine the timing of migration, breeding, and primary molt for Yellow Warblers (Dendroica petechia), Yellow‐rumped Warblers (D. coronata coronata), American Redstarts (Setophaga ruticilla), Ovenbirds (Seiurus aurocapilla), and Canada Warblers (Wilsonia canadensis) at a study site in Alberta, Canada. Hatching date did not differ among species (P= 0.63), with means ranging from 27 June to 3 July. All species began primary molt between 12 July and 18 July, near the expected fledging date of offspring, and therefore all species exhibited overlap between postfledging parental care and molt. The duration of primary molt ranged from 28 d for Canada Warblers to 69 d for Yellow‐rumped Warblers. Yellow Warblers, Yellow‐rumped Warblers, and American Redstarts began autumn migration having completed about 50% of their primary molt. However, Ovenbirds departed when 21% of molt was complete, and Canada Warblers departed 2 d after completing molt. For all five species of warblers, molt did not overlap with nest‐bound breeding activities. However, molt did overlap with both postfledging care and migration. This suggests that initiating migration as soon as possible is important, possibly because earlier arrival on the wintering grounds may improve access to high quality winter habitat. Overall, warblers may maximize individual fitness by combining life‐history events that result in overlapping portions of the breeding cycle, molt, and migration. 相似文献
15.
Methods to obtain moult data from wild birds have not changed much over the last century and most studies still depend on checking museum specimens or capturing birds. Here we assess the applicability of systematic field photography for detecting and scoring moult in adult Black Skimmers Rynchops niger from southern Brazil. Moult data extracted from photographs have a high within‐ (RGLMM = 0.98) and between‐observer repeatability (RGLMM = 0.97) and show very good fit to current Underhill–Zucchini moult models (R2 = 0.75). Photography offers the advantages of being less invasive, requiring less equipment and human effort, being feasible in areas where captures may not be possible, and causing less disturbance, so enhancing the number of sampled individuals. 相似文献
16.
B. V. Timms 《Hydrobiologia》1981,79(3):233-238
Lakes Purrembete, Bullenmerri and Gnotuk are relatively deep lakes with salinities of 0.4, 8 and 58 respectively. From Carbon-14 experiments conducted monthly over a year annual primary production was 96.2, 182.1 and 90.1 gCm-2. These values correlate well with chlorophyll-a in Purrumbete and Bullenmerri, but not in Gnotuk. There is considerable dark fixation in both the saline lakes. 相似文献
17.
Jennifer D. McCabe Brian J. Olsen David Hiebeler 《Evolution; international journal of organic evolution》2016,70(9):2145-2154
Suture zones are areas where range contact zones and hybrid zones of multiple taxa are clustered. Migratory divides, contact zones between divergent populations that breed adjacent to one another but use different migratory routes, are a particular case of suture zones. Although multiple hypotheses for both the formation and maintenance of migratory divides have been suggested, quantitative tests are scarce. Here, we tested whether a novel factor, prevailing winds, was sufficient to explain both the evolution and maintenance of the Cordilleran migratory divide using individual‐based models. Empirical observations of eastern birds suggest a circuitous migratory route across Canada before heading south. Western breeders, however, travel south along the Pacific coast to their wintering grounds. We modeled the effect of wind on bird migratory flights by allowing them to float at elevation using spatially explicit modeled wind data. Modeled eastern birds had easterly mean trajectories, whereas western breeders showed significantly more southern trajectories. We also determined that a mean airspeed of 18.5 m s–1 would be necessary to eliminate this difference in trajectory, a speed that is achieved by waterfowl and shorebirds, but is faster than songbird flight speeds. These results lend support for the potential importance of wind in shaping the phylogeographic history of North American songbirds. 相似文献
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Ardente A Chinnadurai S De Voe R Stringer E Webb T Ireland J Saker K 《Journal of medical primatology》2011,40(3):181-187
Background Lengthy social separation and prolonged fasting time contribute to increased risks associated with anesthesia in captive primates. This study is an initial attempt to identify a safe pre‐anesthetic fasting procedure by identifying gastric emptying time (GET) and gastrointestinal transit time (GTT) of captive chimpanzees, Pan troglodytes. Methods Seven adult chimpanzees at the North Carolina Zoo immobilized for annual physical examinations were fed barium‐impregnated polyethylene spheres to measure GET. Eleven animals were individually fed a color dye marker and fecal passage was observed to determine GTT. Results Gastric emptying time (GET) was approximated to be >3 hours but <16 hours. The mean GTT was 16.5 hours. Conclusions This study indicates that a fasting time of 3 hours would allow for complete gastric emptying and could potentially replace the current overnight fast (≥16 hour) to help minimize complications associated with pre‐anesthetic fasting in captive primates. 相似文献