Animal Migration最新文献

{"title":"Estimating geolocator accuracy for a migratory songbird using live ground-truthing in tropical forest","authors":"E. McKinnon, Calandra Q. Stanley, K. Fraser, Maggie M. MacPherson, Garth Casbourn, P. Marra, Colin E. Studds, Nora E. Diggs, B. Stutchbury","doi":"10.2478/ami-2013-0001","DOIUrl":"https://doi.org/10.2478/ami-2013-0001","url":null,"abstract":"Abstract Miniaturized light-level geolocators allow year-round tracking of small migratory birds, but most studies use calibration only at breeding sites to estimate geographic positions. Ground-truthing of positions in tropical habitat is needed to determine how accurate breeding site calibrations (i.e. sun elevations) are for estimating location of winter sites. We tested the accuracy of geographic assignments using geolocator data collected from Wood Thrushes (Hylocichla mustelina) in Central America. For a given light threshold, sun elevation angle was higher in the tropics than at breeding sites and also varied significantly at tropical winter sites between wet (Oct- Dec) and dry (Jan-Mar) seasons. However, estimation of Wood Thrush territory latitude did not differ significantly when using breeding or tropical dry season sun elevation. Average error in assignment to tropical sites was 365 ± 97 km (0.2-4.4°) in latitude. To obtain the best latitude estimates in the tropics with geolocators, we recommend using locations during the dry season where sun elevations are closer to those measured at breeding sites. We emphasize the importance of longitude in assigning forest birds to unknown sites; longitude estimates for Wood Thrushes in the tropics were, on average, within 66 ± 13 km (0-0.6°) of actual longitude. Latitude estimates were more accurate (180 ± 48 km) when assigning birds to breeding sites using deployments of geolocators in the tropics. Studies of species that are territorial in winter could collect more accurate migratory connectivity data by deploying geolocators at tropical wintering sites.","PeriodicalId":52354,"journal":{"name":"Animal Migration","volume":"1 1","pages":"31 - 38"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2478/ami-2013-0001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69120473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multi-isotope (δ13C, δ15N, δ2H) approach to connecting European breeding and African wintering populations of barn swallow (Hirundo rustica)","authors":"K. Hobson, A. Møller, Steven L Van Wilgenburg","doi":"10.2478/ami-2012-0002","DOIUrl":"https://doi.org/10.2478/ami-2012-0002","url":null,"abstract":"A multi-isotope (δ13C, δ15N, δ2H) approach to connecting European breeding and African wintering populations of barn swallow (Hirundo rustica) Establishing links between breeding and wintering populations of longdistance migratory birds and other animals is fundamental to several aspects of migration research. However, severe limitations in our ability to track small-bodied migratory species still limits this field despite several recent technological breakthroughs. The measurement of naturally occurring stable isotopes of several elements in the tissues of migrants that travel across isotopic gradients or isoscapes has the potential to identify large scale migratory connectivity without some of the biases associated with the use of extrinsic markers. We investigated migratory connectivity between European breeding and African wintering populations of barn swallow (Hirundo rustica) by comparing feather isotope (δ13C, δ15N, δ2H) values with those expected from previously established feather isotopic clusters for Africa. We used a likelihood approach to assigning individuals to molt origins that also made use of prior information provided by ring recoveries as part of the EURING and SAFRING ringing efforts. We found evidence for strong isotopic spatial structure in the dataset, supporting the notion of a migratory divide in Europe with birds breeding in the Netherlands, Denmark, Germany and Eastern Europe wintering in southern Africa and virtually all samples from Switzerland westward being assigned to clusters in the northern portion of the species’ winter range. Individuals from the United Kingdom were assigned to areas including Namibia, Botswana, northern South Africa, and along the coast of Mozambique and Tanzania. Birds wintering in the northernmost region of the wintering grounds tended to breed in the southernmost region of the breeding grounds, providing some evidence of leap-frog migration. We detected a strong latitudinal threshold in feather δ13C in Europe for African-grown feathers, suggesting that birds breeding in southern Europe (< 50° Latitude) primarily used C3-dominated habitats in Africa, whereas birds in northern Europe (> 53° Latitude) primarily used C4-dominated habitats. Our results emphasize the power in using a multi-isotope approach to assign individuals and populations to known continental-scale isoscapes and the advantages of combining isotopic and conventional (ring recovery) information within a Bayesian assignment framework.","PeriodicalId":52354,"journal":{"name":"Animal Migration","volume":"1 1","pages":"22 - 8"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2478/ami-2012-0002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69120417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strong Migratory Connectivity in a Declining Arctic Passerine","authors":"C. Macdonald, K. Fraser, H. Gilchrist, T. K. Kyser, J. Fox, O. Love","doi":"10.2478/ami-2012-0003","DOIUrl":"https://doi.org/10.2478/ami-2012-0003","url":null,"abstract":"Abstract Determining how animal populations are linked in space and time is important for identifying factors influencing population dynamics and for effective conservation and management. Arctic-breeding migratory passerines are declining and at risk due to forecasted climate change, but are a challenge to monitor due to their inaccessible breeding locations, long-distance migration routes and small body size. For the first time, we combine sub-gram geolocator technology and stable-isotope analysis with mark-recapture (banding) and citizen science data to determine patterns of migratory connectivity for multiple populations of a declining North American Arctic-breeding passerine, snow bunting (Plectrophenax nivalis). We show strong evidence for an east-west parallel migratory system, with Hudson Bay acting as a migratory divide. While band recoveries suggest strong migratory connectivity among eastern wintering populations (more than 95% of band recoveries reveal connections between western Greenland and eastern North America), novel application of geolocators and stable-hydrogen isotope analysis to a Canadian breeding population revealed a high degree of migratory connectivity within western North American wintering populations. Our results also show distinct differences in migratory distance between eastern and western populations, and illustrate how applying multiple techniques can effectively be used to track migration patterns of remote populations. Differences in annual distribution and migratory distance suggest that separate consideration of eastern and western wintering populations may improve future conservation and management efforts for this species.","PeriodicalId":52354,"journal":{"name":"Animal Migration","volume":"1 1","pages":"23 - 30"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2478/ami-2012-0003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69120460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geolocators reveal three consecutive wintering areas in the thrush nightingale","authors":"R. Stach, S. Jakobsson, Cecilia Kullberg, T. Fransson","doi":"10.2478/ami-2012-0001","DOIUrl":"https://doi.org/10.2478/ami-2012-0001","url":null,"abstract":"The winter distribution of many migratory birds wintering in tropical Africa is poorly known. After the crossing of the Sahara Desert, some long-distance migrants typically stay in the Sahel zone for an extended period before continuing migration to their main wintering areas south of the equator. Here we show how two thrush nightingales (Luscinia luscinia) fitted with light-level geolocators, after a six to seven week long stay in the Sahel zone of Sudan, moved to an intermediate area in northern Kenya for a month-long stay before continuing to their final wintering areas in southern Africa. These data indicate that thrush nightingales may use three consecutive wintering sites during their stay in Africa. The migratory movements in Africa between wintering sites are well-coordinated with high precipitation in these areas, suggesting that thrush nightingales track peaks of insect abundance occurring after rains. This three-stage wintering strategy has, to our knowledge, previously not been described, and shows that long-distance migrants can have complex wintering behaviour.","PeriodicalId":52354,"journal":{"name":"Animal Migration","volume":"1 1","pages":"1 - 7"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2478/ami-2012-0001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69120754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}