5 research outputs found

    Contrasting strategies for wing‐moult and pre‐migratory fuelling in western and eastern populations of common whitethroat Sylvia communis

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    Trade‐offs between moult and fuelling in migrant birds vary with migration distance and the environmental conditions they encounter. We compared wing moult and fuelling at the northern and southern ends of migration in two populations of adult Common Whitethroats Sylvia communis. The western population moults most remiges at the breeding grounds in Europe (e.g. Poland) and migrates 4000–5000 km to western Africa (e.g. Nigeria). The eastern population moults all remiges at the non‐breeding grounds and migrates 7000–10 000 km from western Asia (e.g. southwestern Siberia) to eastern and southern Africa. We tested the hypotheses that: (1) Whitethroats moult their wing feathers slowly in South Africa, where they face fewer time constraints than in Poland, and (2) fuelling is slower when it coincides with moulting (Poland, South Africa) than when it occurs alone (Siberia, Nigeria). We estimated moult timing of primaries, secondaries and tertials from moult records of Polish and South African Whitethroats ringed in 1987–2017 and determined fuelling patterns from the body mass of Whitethroats ringed in all four regions. The western population moulted wing feathers in Poland over 55 days (2 July–26 August) at a varying rate, up to 13 feathers simultaneously, but fuelled slowly until departure in August–mid‐September. In Nigeria, during the drier period of mid‐February–March they fuelled slowly, but the fuelling rate increased three‐fold in April–May after the rains before mid‐April–May departure. The eastern population did not moult in Siberia but fuelled three times faster before mid‐July–early August departure than did the western birds moulting in Poland. In South Africa, the Whitethroats moulted over 57 days (2 January–28 February) at a constant rate of up to nine feathers simultaneously and fuelled slowly from mid‐December until mid‐April–May departure. These results suggest the two populations use contrasting strategies to capitalize on food supplies before departure from breeding and non‐breeding grounds.Appendix S1. Fig. S1. Moult timing and sequence of each wing feather for western (Poland–Nigeria) and eastern (Siberia–South Africa) Whitethroats. Fig. S2. The number of wing flight feathers growing simultaneously with the feather on the X‐axis for Common Whitethroats in Poland and in South Africa. Table S1. Mean relative mass of flight feathers in adult Common Whitethroats expressed as a percentage of the total mass of all wing feathers treated as 100%, and as percentage of the total mass of all primaries (P1–P9) treated as 100%. Table S2. Moult sequence and moult parameters of separate wing feathers for adult Common Whitethroats caught in July–October 2013–2016 in Poland. Table S3. Moult sequence and moult parameters of separate wing feathers for adult Common Whitethroats caught in November–April 1987–2017 in South Africa. Table S4. Underhill–Zucchini moult models used to determine the effect of region where moult takes place (see Fig. 1) on moult parameters estimated for all primaries, secondaries and tertials jointly in adult Common Whitethroats caught in July–October 2013–2016 in Poland and in November–April 1987–2017 in South Africa. Table S5. Mean wing lengths of Whitethroats caught in the four study regions (Fig. 1), considering the moult status of measured wings. Table S6. Comparison of primary moult rates estimated by Underhill–Zucchini models for Whitethroats in Poland and in South Africa (Tables S2 and S3) with those for other insectivorous passerine migrants.Appendix S2. Datasets used in the study.Polish ringing stations were supported by the Ministry of Higher Education (‘SPUB’ grants). This study was supported by a research grant from the National Research Foundation (NRF) of South Africa, and the National Centre for Research and Development (NCBR), Poland, within the Poland‐South Africa Agreement on Science and Technology (PL‐RPA/BEW/01/2016).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1474-919X2020-10-01hj2019Oral Pathology and Oral Biolog

    A global threats overview for Numeniini populations: synthesising expert knowledge for a group of declining migratory birds

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    The Numeniini is a tribe of thirteen wader species (Scolopacidae, Charadriiformes) of which seven are near-threatened or globally threatened, including two critically endangered. To help inform conservation management and policy responses, we present the results of an expert assessment of the threats that members of this taxonomic group face across migratory flyways. Most threats are increasing in intensity, particularly in non-breeding areas, where habitat loss resulting from residential and commercial development, aquaculture, mining, transport, disturbance, problematic invasive species, pollution and climate change were regarded as having the greatest detrimental impact. Fewer threats (mining, disturbance, problematic native species and climate change) were identified as widely affecting breeding areas. Numeniini populations face the greatest number of non-breeding threats in the East Asian-Australasian Flyway, especially those associated with coastal reclamation; related threats were also identified across the Central and Atlantic Americas, and East Atlantic flyways. Threats on the breeding grounds were greatest in Central and Atlantic Americas, East Atlantic and West Asian flyways. Three priority actions were associated with monitoring and research: to monitor breeding population trends (which for species breeding in remote areas may best be achieved through surveys at key non-breeding sites), to deploy tracking technologies to identify migratory connectivity, and to monitor land-cover change across breeding and non-breeding areas. Two priority actions were focused on conservation and policy responses: to identify and effectively protect key non-breeding sites across all flyways (particularly in the East Asian - Australasian Flyway), and to implement successful conservation interventions at a sufficient scale across human-dominated landscapes for species’ recovery to be achieved. If implemented urgently, these measures in combination have the potential to alter the current population declines of many Numeniini species and provide a template for the conservation of other groups of threatened species

    Transverse momentum spectra of charged particles in proton–proton collisions at √s=900 GeV with ALICE at the LHC

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    The inclusive charged particle transverse momentum distribution is measured in proton–proton collisions at s=900 GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region (|η|<0.8) over the transverse momentum range 0.15<pT<10 GeV/c. The correlation between transverse momentum and particle multiplicity is also studied. Results are presented for inelastic (INEL) and non-single-diffractive (NSD) events. The average transverse momentum for |η|<0.8 is 〈pT〉INEL=0.483±0.001 (stat.)±0.007 (syst.) GeV/c and 〈pT〉NSD=0.489±0.001 (stat.)±0.007 (syst.) GeV/c, respectively. The data exhibit a slightly larger 〈pT〉 than measurements in wider pseudorapidity intervals. The results are compared to simulations with the Monte Carlo event generators PYTHIA and PHOJET

    Suppression of charged particle production at large transverse momentum in central Pb–Pb collisions at √sNN=2.76 TeV

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    Inclusive transverse momentum spectra of primary charged particles in Pb–Pb collisions at √sNN=2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0–5% and 70–80% of the hadronic Pb–Pb cross section. The measured charged particle spectra in |η|<0.8 and 0.3<pT<20 GeV/c are compared to the expectation in pp collisions at the same sNN, scaled by the number of underlying nucleon–nucleon collisions. The comparison is expressed in terms of the nuclear modification factor RAA. The result indicates only weak medium effects (RAA≈0.7) in peripheral collisions. In central collisions, RAA reaches a minimum of about 0.14 at pT=6–7 GeV/c and increases significantly at larger pT. The measured suppression of high-pT particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb–Pb collisions at the LHC

    Two-pion Bose–Einstein correlations in central Pb–Pb collisions at √sNN=2.76 TeV

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    The first measurement of two-pion Bose–Einstein correlations in central Pb–Pb collisions at √sNN=2.76 TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC
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