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José Pedro Granadeiro - One of the best experts on this subject based on the ideXlab platform.
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Quantifying population size of migrant birds at Stopover Sites: combining count data with Stopover length estimated from stable isotope analysis
Methods in Ecology and Evolution, 2017Co-Authors: Teresa Catry, Pedro M. Lourenço, José Pedro GranadeiroAbstract:Regular counts of migrating animals at Stopover Sites have been used as a measure of site importance at the global scale as well as for monitoring long-term population changes. However, migratory passage can last for several weeks and the turnover rate of individuals is often high, preventing the use of peak counts to estimate the total number of migrants. This estimate can be achieved, however, by combining count data with information on Stopover length. Here, we developed a new method to quantify the total number of migrant birds using Stopover areas hosting overlapping populations of local (breeding or wintering) and passage individuals of a given species. We illustrate the application of this method by estimating the number of spring migrant dunlins Calidris alpina stopping over at the Tagus estuary (Portugal). We used carbon and nitrogen isotopic signatures in toenails to identify migrants and to estimate their proportion in total counts. We then employed isotopic clock models to determine time since arrival (TSA) of individuals from signatures in red blood cells and plasma and, using a simulation approach, we derived the relationship between TSA and Stopover length. Finally, by dividing the number of migrants.day (obtained from counts) by the Stopover length, we assessed the size of the migrant population. We demonstrated that Stopover length can be directly predicted from mean TSA values of birds sampled during migration, regardless of variations in (1) migratory rate, that is, the phenology of arrivals throughout the migratory period and (2) the number of birds involved in the migratory event. Migrant dunlins stayed on average 7.5 days at the Tagus estuary during spring migration, which combined with count data resulted in an estimate of c. 30,000 passage dunlins, using the study site. Our novel approach is not strict in its assumptions, and therefore can be customised to the specificities of different taxa and study areas. Estimates of total number of migrants along migratory flyways are critical to identify priority Sites for conservation action. In fact, single Stopover Sites may host a very significant proportion of a global population albeit for a short period.
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Use of stable isotope fingerprints to assign wintering originand trace shorebird movements along the East AtlanticFlyway
Basic and Applied Ecology, 2016Co-Authors: Teresa Catry, Theunis Piersma, Pedro Lourenço, Ricardo Lopes, Pierrick Bocher, Camilo Carneiro, José Alves, Philippe Delaporte, Stuart Bearhop, José Pedro GranadeiroAbstract:2015AbstractMigratory connectivity can be defined as the flux of individuals or populations among areas between stages of an animal’s lifecycle. Many shorebird species perform long-distance migrations and while moving between breeding and wintering grounds,they depend on a network of intermediate wetlands (Stopover Sites) where populations of different origins extensively overlap.The difficulty to discriminate such populations represents a serious obstacle to the identification of the links between breedingor wintering areas and Stopover Sites, and also precludes the estimation of demographic parameters for each population. In thisstudy, we test if linear discriminant models based on stable carbon and nitrogen isotope ratios in toenails can be used to identifypopulations of several shorebird species of different wintering origins overlapping at two Stopover Sites of the East AtlanticFlyway. In addition, we evaluate the ability of this approach to infer migratory phenological patterns of shorebirds. Lineardiscriminant analyses performed overall well in distinguishing the isotopic signals of birds from wintering areas (in France,Portugal, Morocco, Mauritania and Guinea-Bissau) in most species, correctly classifying over 80% (n = 542) of all wintering individuals sampled at these areas. Assignment rates of shorebirds captured during spring migration were also high (96%,n = 323) at the Tejo estuary, Portugal, but lower (40%, n = 185) at Marennes-Oléron Bay in France, and also differed amongspecies. A large proportion of spring migrants captured in Portugal and France were assigned to Banc d’Arguin in Mauritania,the most important wintering area in the flyway. Phenological patterns derived for dunlins (Calidris alpina), common ringedplovers (Charadrius hiaticula) and grey plovers (Pluvialis squatarola) suggest that the first northward migrants started arrivingat the Tejo estuary during the second half of March, with peaking numbers occurring during April or May.
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discriminating geographic origins of migratory waders at Stopover Sites insights from stable isotope analysis of toenails
Journal of Avian Biology, 2012Co-Authors: Teresa Catry, Ricardo C Martins, José Pedro GranadeiroAbstract:In this study we test the potential of stable isotope analysis to reveal wintering origins of waders mixing at Stopover Sites, using the dunlin Calidris alpina as a case study. We determined stable carbon ( δ 13 C) and nitrogen ( δ 15 N) isotope signatures of toenails of dunlins captured during winter at reference Sites along the East-Atlantic Flyway, from Mauritania to the United Kingdom. Afterwards, during spring migration, dunlins were sampled at the Tagus estuary, Portugal, and assigned to their wintering grounds according to their stable isotope signatures. Toenails from wintering dunlins at diff erent Sites had signifi cantly diff erent δ 13 C and δ 15 N signatures, despite some overlap in isotopic carbon ratios of birds from Morocco, Portugal and the UK. Among birds sampled during migration in Portugal, we found a clear bimodal pattern in δ 13 C values, corresponding to passage migrants from Mauritania (enriched δ 13 C values) and wintering birds from the Tagus estuary (depleted δ 13 C values). Th e fi rst passage migrants from Mauritania appeared at the Tagus estuary by the end of March, with peak numbers during late April and early May. Our study provides evidence that isotopic signatures of toenails can play a determinant role in tracing the wintering origins of migrant dunlins at their Stopover areas. Toenails, instead of feathers, can be the powerful and innovating tissue to sample in wader studies, allowing to bridge the gap in the fi eld of migratory connectivity between Sites used in diff erent phases of the life cycle of waders.
Teresa Catry - One of the best experts on this subject based on the ideXlab platform.
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Quantifying population size of migrant birds at Stopover Sites: combining count data with Stopover length estimated from stable isotope analysis
Methods in Ecology and Evolution, 2017Co-Authors: Teresa Catry, Pedro M. Lourenço, José Pedro GranadeiroAbstract:Regular counts of migrating animals at Stopover Sites have been used as a measure of site importance at the global scale as well as for monitoring long-term population changes. However, migratory passage can last for several weeks and the turnover rate of individuals is often high, preventing the use of peak counts to estimate the total number of migrants. This estimate can be achieved, however, by combining count data with information on Stopover length. Here, we developed a new method to quantify the total number of migrant birds using Stopover areas hosting overlapping populations of local (breeding or wintering) and passage individuals of a given species. We illustrate the application of this method by estimating the number of spring migrant dunlins Calidris alpina stopping over at the Tagus estuary (Portugal). We used carbon and nitrogen isotopic signatures in toenails to identify migrants and to estimate their proportion in total counts. We then employed isotopic clock models to determine time since arrival (TSA) of individuals from signatures in red blood cells and plasma and, using a simulation approach, we derived the relationship between TSA and Stopover length. Finally, by dividing the number of migrants.day (obtained from counts) by the Stopover length, we assessed the size of the migrant population. We demonstrated that Stopover length can be directly predicted from mean TSA values of birds sampled during migration, regardless of variations in (1) migratory rate, that is, the phenology of arrivals throughout the migratory period and (2) the number of birds involved in the migratory event. Migrant dunlins stayed on average 7.5 days at the Tagus estuary during spring migration, which combined with count data resulted in an estimate of c. 30,000 passage dunlins, using the study site. Our novel approach is not strict in its assumptions, and therefore can be customised to the specificities of different taxa and study areas. Estimates of total number of migrants along migratory flyways are critical to identify priority Sites for conservation action. In fact, single Stopover Sites may host a very significant proportion of a global population albeit for a short period.
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Use of stable isotope fingerprints to assign wintering originand trace shorebird movements along the East AtlanticFlyway
Basic and Applied Ecology, 2016Co-Authors: Teresa Catry, Theunis Piersma, Pedro Lourenço, Ricardo Lopes, Pierrick Bocher, Camilo Carneiro, José Alves, Philippe Delaporte, Stuart Bearhop, José Pedro GranadeiroAbstract:2015AbstractMigratory connectivity can be defined as the flux of individuals or populations among areas between stages of an animal’s lifecycle. Many shorebird species perform long-distance migrations and while moving between breeding and wintering grounds,they depend on a network of intermediate wetlands (Stopover Sites) where populations of different origins extensively overlap.The difficulty to discriminate such populations represents a serious obstacle to the identification of the links between breedingor wintering areas and Stopover Sites, and also precludes the estimation of demographic parameters for each population. In thisstudy, we test if linear discriminant models based on stable carbon and nitrogen isotope ratios in toenails can be used to identifypopulations of several shorebird species of different wintering origins overlapping at two Stopover Sites of the East AtlanticFlyway. In addition, we evaluate the ability of this approach to infer migratory phenological patterns of shorebirds. Lineardiscriminant analyses performed overall well in distinguishing the isotopic signals of birds from wintering areas (in France,Portugal, Morocco, Mauritania and Guinea-Bissau) in most species, correctly classifying over 80% (n = 542) of all wintering individuals sampled at these areas. Assignment rates of shorebirds captured during spring migration were also high (96%,n = 323) at the Tejo estuary, Portugal, but lower (40%, n = 185) at Marennes-Oléron Bay in France, and also differed amongspecies. A large proportion of spring migrants captured in Portugal and France were assigned to Banc d’Arguin in Mauritania,the most important wintering area in the flyway. Phenological patterns derived for dunlins (Calidris alpina), common ringedplovers (Charadrius hiaticula) and grey plovers (Pluvialis squatarola) suggest that the first northward migrants started arrivingat the Tejo estuary during the second half of March, with peaking numbers occurring during April or May.
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discriminating geographic origins of migratory waders at Stopover Sites insights from stable isotope analysis of toenails
Journal of Avian Biology, 2012Co-Authors: Teresa Catry, Ricardo C Martins, José Pedro GranadeiroAbstract:In this study we test the potential of stable isotope analysis to reveal wintering origins of waders mixing at Stopover Sites, using the dunlin Calidris alpina as a case study. We determined stable carbon ( δ 13 C) and nitrogen ( δ 15 N) isotope signatures of toenails of dunlins captured during winter at reference Sites along the East-Atlantic Flyway, from Mauritania to the United Kingdom. Afterwards, during spring migration, dunlins were sampled at the Tagus estuary, Portugal, and assigned to their wintering grounds according to their stable isotope signatures. Toenails from wintering dunlins at diff erent Sites had signifi cantly diff erent δ 13 C and δ 15 N signatures, despite some overlap in isotopic carbon ratios of birds from Morocco, Portugal and the UK. Among birds sampled during migration in Portugal, we found a clear bimodal pattern in δ 13 C values, corresponding to passage migrants from Mauritania (enriched δ 13 C values) and wintering birds from the Tagus estuary (depleted δ 13 C values). Th e fi rst passage migrants from Mauritania appeared at the Tagus estuary by the end of March, with peak numbers during late April and early May. Our study provides evidence that isotopic signatures of toenails can play a determinant role in tracing the wintering origins of migrant dunlins at their Stopover areas. Toenails, instead of feathers, can be the powerful and innovating tissue to sample in wader studies, allowing to bridge the gap in the fi eld of migratory connectivity between Sites used in diff erent phases of the life cycle of waders.
Benno Lüthi - One of the best experts on this subject based on the ideXlab platform.
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Migration Routes and Stopover Sites of Upland Geese Chloephaga Picta in South America
Avian Biology Research, 2018Co-Authors: Julieta Pedrana, Klemens Pütz, Lucia Bernad, Juan Pablo Seco Pon, Antonella Gorosabel, Sebastian D. Muñoz, Juan Pablo Isacch, Ricardo Matus, Olivia Blank, Benno LüthiAbstract:The Upland Goose (Chloephaga picta picta) is a migratory species of South America, which breeds from September to April in Patagonia (Argentina and Chile) and winters from May to September in the southern Pampas (Argentina). Despite some protection in both countries, this species is still persecuted and large numbers are killed by unregulated hunting. Therefore, precise knowledge of their migratory routes is vital to ensure protection of necessary resources and Sites throughout the year. We deployed five miniaturised satellite transmitters on adult Upland Geese to gather data about breeding, wintering and Stopover Sites all along their migratory routes. We aimed to identify important areas in the wintering and breeding grounds through kernel density analyses, and to match these Sites along the migration routes with protected areas. Tracked birds exhibited different migration routes and reached different breeding grounds. Two individuals travelled from their wintering grounds in Buenos Aires province to their presumed breeding areas in southern Patagonia. However, we also found different Stopover Sites from another bird in northern Patagonia, from the ones postulated before, and evidence that some Upland Geese are not large-scale migrants. Our results highlight a considerable amount of plasticity in Upland Geese migratory behaviour. This study represents an essential first step towards identifying important Stopover Sites along the Upland Geese flyways and it also highlights the lack of protected habitats along most of their migration routes.
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migration routes and Stopover Sites of upland geese chloephaga picta in south america
Avian Biology Research, 2018Co-Authors: Julieta Pedrana, Klemens Pütz, Lucia Bernad, Juan Pablo Seco Pon, Antonella Gorosabel, Sebastian D. Muñoz, Juan Pablo Isacch, Ricardo Matus, Olivia Blank, Benno LüthiAbstract:The Upland Goose (Chloephaga picta picta) is a migratory species of South America, which breeds from September to April in Patagonia (Argentina and Chile) and winters from May to September in the s...
Hiroyoshi Higuchi - One of the best experts on this subject based on the ideXlab platform.
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Network analysis of potential migration routes for Oriental White Storks (Ciconia boyciana)
Ecological Research, 2004Co-Authors: Hiroto Shimazaki, Masayuki Tamura, Yury Darman, Vladimir Andronov, Mikhail P. Parilov, Meenakshi Nagendran, Hiroyoshi HiguchiAbstract:From 1998 through to 2000, we satellite-tracked the movements of 13 Oriental White Storks (Ciconia boyciana) on their autumnal migration in order to identify their important Stopover Sites for preserving links from the Russian Far East breeding Sites to the wintering Sites in south-eastern China. New analytical methods of satellite tracking data were employed to derive robust information on the locations of stay Sites, the number of Stopovers made during migration, and the distance traveled without making Stopovers. Based on the derived information, we modeled a stay site network as an abstraction of the storks’ potential migration routes from their breeding Sites to wintering Sites. Using network analysis techniques, we explored how the loss of Stopover Sites could affect the connectivity of potential migration routes. The results suggested that if the seashore Stopover Sites facing Bohai Bay in eastern China were lost, the storks’ wintering Sites along the Yangtze River in south-eastern China would be isolated. Among the seashore Stopover Sites, Jiantuozhi Gley Mire (39.185°N, 118.627°E), located on the northern seashore of Bohai Bay, was considered particularly important for migrating storks, because it was used every year by the storks we tracked. If conservation needs of this critically located site fail to be addressed, the stay site network of storks can create weak links in the chain of migration and, if ‘broken’, storks will have great difficulties in completing their autumnal migration.
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migration routes and important Stopover Sites of endangered oriental white storks ciconia boyciana as revealed by satellite tracking
Memoirs of National Institute of Polar Research. Special issue, 2004Co-Authors: Hiroto Shimazaki, Masayuki Tamura, Hiroyoshi HiguchiAbstract:From 1998 through 2000, we tracked the autumnal migrations of 13 oriental white storks (Ciconia boyciana) by satellite in order to identify their important Stopover Sites. The storks were successfully tracked and provided data on partial (n = 4) or complete (n = 9) autumnal migration between the Russian Far East breeding Sites and the wintering Sites in southeastern China. Twenty-seven Stopover Sites were identified, the most important of which were in Tonghe Peat Moor (46.095°N, 128.942°E), Momoge Nature Reserve (45.945°N, 123.939°E), and Jiantuozhi Gley Mire (39.221°N, 118.672°E). The connected- ness between each Stopover site and its surrounding stay Sites was also evaluated; the results suggested that the Stopover Sites situated on the seashores of Liaodong Bay, Bohai Bay, and Laizhou Bay in eastern China are less connected than the others. We concluded that, among the Sites studied, Jiantuozhi Gley Mire on the northern shore of Bohai Bay should have a higher priority for protection for two reasons: it is used by many storks, in common, for rel- atively long periods; and it is at higher risk of being isolated from the migration route net- work.
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difference in migration pattern between adult and immature birds using satellites
The Auk, 2002Co-Authors: Mutsuyuki Ueta, Hiroyoshi HiguchiAbstract:Abstract We satellite-tracked Steller's Sea Eagles (Haliaeetus pelagicus), Black-faced Spoonbills (Platalea minor), and White-naped Cranes (Grus vipio) to determine migration routes and Stopover tactics of adult and immature birds. During spring migration, there were no significant differences between adult and immature birds in total migration distance and distance between Stopover Sites, but the migration period and resting period at Stopover Sites were significantly longer in immature individuals. There are two possible tactics for migrating without expending fat stores: longer rests or shorter migration distances between Stopover Sites. Our results suggest that immature birds try to increase fat stores by increasing time available for foraging at Stopover Sites.
Christopher G. Guglielmo - One of the best experts on this subject based on the ideXlab platform.
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Passerine migrant Stopover duration and spatial behaviour at an urban Stopover site
Acta Oecologica, 2010Co-Authors: Chad L. Seewagen, Eric J. Slayton, Christopher G. GuglielmoAbstract:Migration routes of many NearcticeNeotropical landbirds pass through the most urbanized regions of North America. Migrants are known to use urban habitats as Stopover Sites and often occur in cities at exceptional density; yet knowledge of migrant behaviour and ecology in such places is surprisingly limited. We radio-tracked ovenbirds (Seiurus aurocapillus) during Stopovers in a New York City park to obtain some of the first detailed information on how landbird migrants utilize an urban habitat as a Stopover site. We examined fine-scale movement patterns, home range sizes, Stopover durations, and how arrival condition affected each of these metrics. During both seasons, most birds moved widely throughout the site upon presumed arrival and then either continued migration that night or settled into a more defined area on subsequent days. Area usage varied markedly among individuals during both seasons, ranging 1e16 ha. Stopover durations averaged 3.0 days (range ¼ 1e10 days) during spring and 2.9 days (range ¼ 1e14 days) during autumn. Spatial behaviours and Stopover durations were not influenced by arrival condition during spring, and during autumn only movement rates and displacement distances were significantly (negatively) condition-related. Our findings do not support previous assumptions that urban Stopover habitats are only used by migrants briefly in times of urgency when alternatives are unavailable. At least half of the birds we studied stopped over for multiple days during both seasons, and bird movements were indicative of an ability to search for, locate, and occupy suitable micro-Sites. Ovenbird behaviour in our study site was similar in many ways to what has been observed in recent telemetry studies of ovenbirds and other passerine migrants at various non-urban Stopover Sites.
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Plasma metabolites and migration physiology of semipalmated sandpipers: refueling performance at five latitudes
Oecologia, 2008Co-Authors: James E. Lyons, Jaime A. Collazo, Christopher G. GuglielmoAbstract:Long-distance bird migration is fueled by energy gathered at Stopover Sites along the migration route. The refueling rate at Stopover Sites is a determinant of time spent at Stopovers and impacts the overall speed of migration. Refueling rate during spring migration may influence the fitness of individuals via changes in the probability of successful migration and reproduction during the subsequent breeding season. We evaluated four plasma lipid metabolites (triglycerides, phospholipids, β-OH-butyrate, and glycerol) as measures of refueling rate in free-living semipalmated sandpipers ( Calidris pusilla ) captured at non-breeding areas. We described the spatial and temporal variation in metabolite concentrations among one winter site in the Dominican Republic and four Stopover Sites in the South Atlantic and Mid-Atlantic Coastal Plain regions of North America. Triglycerides and β-OH-butyrate clearly identified spatial variation in refueling rate and Stopover habitat quality. Metabolite profiles indicated that birds had higher refueling rates at one site in the Mid-Atlantic Coastal Plain than at three Sites on the South Atlantic Coastal Plain and one site in the Dominican Republic. Temporal variation in lipid metabolites during the migration season suggested that male semipalmated sandpipers gained more weight at Stopovers on the South Atlantic Coastal Plain than did females, evidence of differential migration strategies for the sexes. Plasma lipid metabolites provide information on migration physiology that may help determine Stopover habitat quality and reveal how migratory populations use Stopover Sites to refuel and successfully complete long-distance migrations.
