Pub Date : 2018-01-02DOI: 10.1080/03078698.2018.1528715
Manuel Polo Aparisi, E. Schöll, S. Hille
ABSTRACT Sexing Marsh Tits Poecile palustris by wing length has long been general practice in Europe but has recently been under discussion again in Great Britain. Although this debate has concentrated on British populations of the subspecies P.p. dresseri, we contribute in two ways – first by studying a population of the nominate form P.p. palustris in eastern Austria and second by applying a multivariate approach to a series of biometric variables alongside wing length. We measured 13 further biometric parameters that are known to differ between sexes and calculated conditional inference trees to identify the best sex-differentiating variable. With no misclassifications detected, we proved wing length to be the most reliable variable to identify sexes throughout age classes, with males exhibiting wings longer than 64 mm. Lengths of sixth, seventh and eighth primaries and of tail feathers could also be used, but sex was identified less accurately (with 4.8–6.7% misclassifications). Other biometric measurements, like body mass and the lengths of tarsometatarsus, bill and remaining primary feathers, were not suitable for sex differentiation.
{"title":"Alpine Marsh Tits Poecile palustris palustris exhibit no clear sexual dimorphism other than in wing length","authors":"Manuel Polo Aparisi, E. Schöll, S. Hille","doi":"10.1080/03078698.2018.1528715","DOIUrl":"https://doi.org/10.1080/03078698.2018.1528715","url":null,"abstract":"ABSTRACT Sexing Marsh Tits Poecile palustris by wing length has long been general practice in Europe but has recently been under discussion again in Great Britain. Although this debate has concentrated on British populations of the subspecies P.p. dresseri, we contribute in two ways – first by studying a population of the nominate form P.p. palustris in eastern Austria and second by applying a multivariate approach to a series of biometric variables alongside wing length. We measured 13 further biometric parameters that are known to differ between sexes and calculated conditional inference trees to identify the best sex-differentiating variable. With no misclassifications detected, we proved wing length to be the most reliable variable to identify sexes throughout age classes, with males exhibiting wings longer than 64 mm. Lengths of sixth, seventh and eighth primaries and of tail feathers could also be used, but sex was identified less accurately (with 4.8–6.7% misclassifications). Other biometric measurements, like body mass and the lengths of tarsometatarsus, bill and remaining primary feathers, were not suitable for sex differentiation.","PeriodicalId":35936,"journal":{"name":"Ringing and Migration","volume":"33 1","pages":"36 - 40"},"PeriodicalIF":0.0,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/03078698.2018.1528715","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48513405","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}
Pub Date : 2017-07-03DOI: 10.1080/03078698.2017.1437886
Ken W. Smith, B. E. Trevis, M. Reed
ABSTRACT We have measured the activity patterns of wintering Green Sandpipers before and after they were fitted with geolocators attached using leg loop harnesses and compared these with a control group of untagged birds. The geolocators and harnesses represented 1.4–1.6% of the body mass of the birds. Although the proportion of time the birds spent feeding increased over the course of the winter, we found no significant effect of tagging. Tagged birds spent significantly more time preening than untagged birds (6.3% overall compared with 4.6% for untagged birds) but the effect decreased with days after tagging. There was no evidence that this small increase in preening activity led to lower survival of the birds or changes in their migration timetable.
{"title":"The effects of leg-loop harnesses and geolocators on the diurnal activity patterns of Green Sandpipers Tringa ochropus in winter","authors":"Ken W. Smith, B. E. Trevis, M. Reed","doi":"10.1080/03078698.2017.1437886","DOIUrl":"https://doi.org/10.1080/03078698.2017.1437886","url":null,"abstract":"ABSTRACT We have measured the activity patterns of wintering Green Sandpipers before and after they were fitted with geolocators attached using leg loop harnesses and compared these with a control group of untagged birds. The geolocators and harnesses represented 1.4–1.6% of the body mass of the birds. Although the proportion of time the birds spent feeding increased over the course of the winter, we found no significant effect of tagging. Tagged birds spent significantly more time preening than untagged birds (6.3% overall compared with 4.6% for untagged birds) but the effect decreased with days after tagging. There was no evidence that this small increase in preening activity led to lower survival of the birds or changes in their migration timetable.","PeriodicalId":35936,"journal":{"name":"Ringing and Migration","volume":"32 1","pages":"104 - 109"},"PeriodicalIF":0.0,"publicationDate":"2017-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/03078698.2017.1437886","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45670211","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}
Pub Date : 2017-07-03DOI: 10.1080/03078698.2017.1426928
W. Brown, Tessa W. Alianell
ABSTRACT Image-based ageing guides of passerine nestlings can produce accurate age estimates. If different species develop similarly, but timing of development differs, creation of a generalised image-based ageing guide for use with nestlings of multiple species is justified if age estimates can be corrected to account for such differences of timing. To explore this idea, inexperienced participants used an image-based ageing guide for Tree Swallow Tachycineta bicolor nestlings to produce age estimates from images of known-age nestling Eastern Bluebirds Sialia sialis and House Wrens Troglodytes aedon. Participants also used a House Wren ageing guide to produce age estimates of nestling Eastern Bluebirds and an Eastern Bluebird ageing guide to produce age estimates of House Wren nestlings (n = 54 total participants and 2565 age estimates). Ages of nestling bluebirds were generally underestimated with the swallow and wren ageing guides, while ages of wrens were generally overestimated with the swallow and bluebird guides. Although the accuracy of age estimates (the percentage within one day of actual age) produced by interspecific guides ranged from 43% to 77% overall, accuracy of estimates corrected using regression analyses increased to better than 80% for all pairwise comparisons. Based on these results, continued development and refinement of a generalised nestling ageing guide is warranted.
{"title":"Do interspecific image-based ageing guides produce accurate estimates of nestling ages? – progress toward development of a generalised ageing guide","authors":"W. Brown, Tessa W. Alianell","doi":"10.1080/03078698.2017.1426928","DOIUrl":"https://doi.org/10.1080/03078698.2017.1426928","url":null,"abstract":"ABSTRACT Image-based ageing guides of passerine nestlings can produce accurate age estimates. If different species develop similarly, but timing of development differs, creation of a generalised image-based ageing guide for use with nestlings of multiple species is justified if age estimates can be corrected to account for such differences of timing. To explore this idea, inexperienced participants used an image-based ageing guide for Tree Swallow Tachycineta bicolor nestlings to produce age estimates from images of known-age nestling Eastern Bluebirds Sialia sialis and House Wrens Troglodytes aedon. Participants also used a House Wren ageing guide to produce age estimates of nestling Eastern Bluebirds and an Eastern Bluebird ageing guide to produce age estimates of House Wren nestlings (n = 54 total participants and 2565 age estimates). Ages of nestling bluebirds were generally underestimated with the swallow and wren ageing guides, while ages of wrens were generally overestimated with the swallow and bluebird guides. Although the accuracy of age estimates (the percentage within one day of actual age) produced by interspecific guides ranged from 43% to 77% overall, accuracy of estimates corrected using regression analyses increased to better than 80% for all pairwise comparisons. Based on these results, continued development and refinement of a generalised nestling ageing guide is warranted.","PeriodicalId":35936,"journal":{"name":"Ringing and Migration","volume":"32 1","pages":"72 - 78"},"PeriodicalIF":0.0,"publicationDate":"2017-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/03078698.2017.1426928","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47768096","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}
Pub Date : 2017-07-03DOI: 10.1080/03078698.2017.1438980
R. H. Walker, R. Robinson, C. Barimore, J. Blackburn, L. Barber, J. Clark, G. Clewley, Diana X. de Palacio, M. Grantham, Bridget M. Griffin, David J. Hodkinson, Allison J. Kew, D. Moss, S. Schäfer, D. Leech
ABSTRACT This is the 80th annual report of the British Trust for Ornithology's Ringing Scheme, incorporating the report of the Nest Record Scheme and covering work carried out and data processed in 2016. BTO and JNCC have used seabird population data to investigate how demographic processes drive population changes, enabling improved population models to be produced. These population models were used to help quantify the risks associated with large-scale infrastructure projects (e.g. windfarms) and recommendations were made concerning approaches to be used in particular circumstances. Density dependence in seabirds, and its potential impact on population models, was also reviewed but little evidence of significant effects was found. Research on the demographic causes of declines in migratory species, undertaken in collaboration with the University of East Anglia, focused on population changes in Willow Warblers Phylloscopus trochilus. Data from the Nest Record Scheme (NRS), Constant Effort Sites scheme (CES) and the Breeding Bird Survey were combined; the results showed that reduced productivity levels in Willow Warblers in the south of Britain were driving the decline. In 2016, 134 CE sites submitted data. Five migrant and two resident species exhibited long-term (1984–2015) declines in abundance while four migrant and six resident species showed declines in productivity. Compared to the five-year mean (2011–15), the abundance of 10 species increased significantly in 2016 with Cetti's Warbler Cettia cetti, Chiffchaff Phylloscopus collybita, Wren Troglodytes troglodytes and Robin Erithacus rubecula abundance at its highest since CES monitoring began. The abundance of three species fell significantly in 2016. Productivity increased for one species in 2016 and decreased significantly for 16 species. Survival rates increased significantly for three species and fell significantly for one. For the first time, the number of Retrapping Adults for Survival submissions passed 200. A total of 59 species were monitored and 24 projects ran for the first time. The most-studied species were Pied Flycatcher Ficedula hypoleuca (23 projects), House Sparrow Passer domesticus (17), Sand Martin Riparia riparia (15) and Starling Sturnus vulgaris (13). Over a million birds (1 051 629) were ringed during the year, comprising 157 653 nestlings, 490 796 first-year birds, 370 019 adults (birds in their second calendar year or older) and 33 161 birds where the age could not be determined. In addition, there were 255 898 recaptures of ringed birds at or near the ringing site. In total, 40 257 recoveries (birds found dead, or recaptured or resighted at least 5 km from the place of ringing) of BTO-ringed birds were reported in 2016. The Appendix highlights a selection of recoveries that have extended our knowledge of movements, as well as longevity records established during the year. NRS submissions in 2016 exceeded 45 000 for the third consecutive year, with a total of 46 5
{"title":"Bird ringing and nest recording in Britain and Ireland in 2016","authors":"R. H. Walker, R. Robinson, C. Barimore, J. Blackburn, L. Barber, J. Clark, G. Clewley, Diana X. de Palacio, M. Grantham, Bridget M. Griffin, David J. Hodkinson, Allison J. Kew, D. Moss, S. Schäfer, D. Leech","doi":"10.1080/03078698.2017.1438980","DOIUrl":"https://doi.org/10.1080/03078698.2017.1438980","url":null,"abstract":"ABSTRACT This is the 80th annual report of the British Trust for Ornithology's Ringing Scheme, incorporating the report of the Nest Record Scheme and covering work carried out and data processed in 2016. BTO and JNCC have used seabird population data to investigate how demographic processes drive population changes, enabling improved population models to be produced. These population models were used to help quantify the risks associated with large-scale infrastructure projects (e.g. windfarms) and recommendations were made concerning approaches to be used in particular circumstances. Density dependence in seabirds, and its potential impact on population models, was also reviewed but little evidence of significant effects was found. Research on the demographic causes of declines in migratory species, undertaken in collaboration with the University of East Anglia, focused on population changes in Willow Warblers Phylloscopus trochilus. Data from the Nest Record Scheme (NRS), Constant Effort Sites scheme (CES) and the Breeding Bird Survey were combined; the results showed that reduced productivity levels in Willow Warblers in the south of Britain were driving the decline. In 2016, 134 CE sites submitted data. Five migrant and two resident species exhibited long-term (1984–2015) declines in abundance while four migrant and six resident species showed declines in productivity. Compared to the five-year mean (2011–15), the abundance of 10 species increased significantly in 2016 with Cetti's Warbler Cettia cetti, Chiffchaff Phylloscopus collybita, Wren Troglodytes troglodytes and Robin Erithacus rubecula abundance at its highest since CES monitoring began. The abundance of three species fell significantly in 2016. Productivity increased for one species in 2016 and decreased significantly for 16 species. Survival rates increased significantly for three species and fell significantly for one. For the first time, the number of Retrapping Adults for Survival submissions passed 200. A total of 59 species were monitored and 24 projects ran for the first time. The most-studied species were Pied Flycatcher Ficedula hypoleuca (23 projects), House Sparrow Passer domesticus (17), Sand Martin Riparia riparia (15) and Starling Sturnus vulgaris (13). Over a million birds (1 051 629) were ringed during the year, comprising 157 653 nestlings, 490 796 first-year birds, 370 019 adults (birds in their second calendar year or older) and 33 161 birds where the age could not be determined. In addition, there were 255 898 recaptures of ringed birds at or near the ringing site. In total, 40 257 recoveries (birds found dead, or recaptured or resighted at least 5 km from the place of ringing) of BTO-ringed birds were reported in 2016. The Appendix highlights a selection of recoveries that have extended our knowledge of movements, as well as longevity records established during the year. NRS submissions in 2016 exceeded 45 000 for the third consecutive year, with a total of 46 5","PeriodicalId":35936,"journal":{"name":"Ringing and Migration","volume":"32 1","pages":"111 - 155"},"PeriodicalIF":0.0,"publicationDate":"2017-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/03078698.2017.1438980","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49653566","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}
Pub Date : 2017-07-03DOI: 10.1080/03078698.2017.1384634
{"title":"Correction to Literák et al., Migration of Black Storks Ciconia nigra at a migratory divide: two different routes used by siblings from one nest and two different routes used by one individual","authors":"","doi":"10.1080/03078698.2017.1384634","DOIUrl":"https://doi.org/10.1080/03078698.2017.1384634","url":null,"abstract":"","PeriodicalId":35936,"journal":{"name":"Ringing and Migration","volume":"32 1","pages":"156 - 156"},"PeriodicalIF":0.0,"publicationDate":"2017-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/03078698.2017.1384634","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41551462","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}
Pub Date : 2017-07-03DOI: 10.1080/03078698.2017.1368570
S. Scebba, M. Sorrenti, Maria Oliveri del Castillo
ABSTRACT From 1998 to 2015, 22 490 fully grown Skylarks were captured and ringed, using mist nets, from October to mid November, along the southern Tyrrhenian coast of Italy. We estimated fat loads and theoretical flight ranges for individual birds, using recorded body mass and visible fat score. The size-specific fat-free body mass, as the body mass of birds with no visible subcutaneous fat deposits, was estimated for all categories of wing length, verifying any differences between males and females identified using wing length; body mass (to 0.1 g) and visible fat score (values 0–6) were recorded in the field. Males were significantly heavier than females and more often had high scores of visible fat. Only a few birds had high fat scores (classes 5 and 6) and the proportion of individuals with no visible fat (class 0) was very low: most birds of both sexes fell into classes 3 or 4. Fat scores were positively correlated with the corresponding average body mass. The predicted flight range indicated that 70% of Skylarks captured would be unable to fly farther than 800 km: they would be able to reach their wintering grounds, spend the winter in Italy or reach the North African coast after a refuelling stop.
{"title":"Masses, fat loads and estimated flight ranges of Skylarks Alauda arvensis captured during autumn migration in southern Italy","authors":"S. Scebba, M. Sorrenti, Maria Oliveri del Castillo","doi":"10.1080/03078698.2017.1368570","DOIUrl":"https://doi.org/10.1080/03078698.2017.1368570","url":null,"abstract":"ABSTRACT From 1998 to 2015, 22 490 fully grown Skylarks were captured and ringed, using mist nets, from October to mid November, along the southern Tyrrhenian coast of Italy. We estimated fat loads and theoretical flight ranges for individual birds, using recorded body mass and visible fat score. The size-specific fat-free body mass, as the body mass of birds with no visible subcutaneous fat deposits, was estimated for all categories of wing length, verifying any differences between males and females identified using wing length; body mass (to 0.1 g) and visible fat score (values 0–6) were recorded in the field. Males were significantly heavier than females and more often had high scores of visible fat. Only a few birds had high fat scores (classes 5 and 6) and the proportion of individuals with no visible fat (class 0) was very low: most birds of both sexes fell into classes 3 or 4. Fat scores were positively correlated with the corresponding average body mass. The predicted flight range indicated that 70% of Skylarks captured would be unable to fly farther than 800 km: they would be able to reach their wintering grounds, spend the winter in Italy or reach the North African coast after a refuelling stop.","PeriodicalId":35936,"journal":{"name":"Ringing and Migration","volume":"32 1","pages":"63 - 71"},"PeriodicalIF":0.0,"publicationDate":"2017-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/03078698.2017.1368570","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47335542","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}
Pub Date : 2017-07-03DOI: 10.1080/03078698.2017.1438367
R. Broughton, J. Clark
ABSTRACT Biometrics, particularly wing length, are commonly used to assign the sex of many birds in species where the plumage is similar for males and females. Virtually all species show some measurement overlap between the sexes, however, and measurement error can add further uncertainty into data sets. This can result in individuals being misclassified as the wrong sex and introducing bias into subsequent analyses, particularly if the life histories of misclassified birds differ from those of others. We used the Marsh Tit Poecile palustris as a case study to examine potential sources of error and bias when assigning sex based on wing length. There was no evidence for a heritability of wing lengths that could result in localised populations of atypical size via a ‘founder effect’, which would otherwise undermine biometric sexing. Additionally, potentially misclassified birds did not differ from others in how long they persisted in the local population, so avoiding any potential bias of misclassification in demographic analyses. Compared to Marsh Tit data collected during intensive studies, the national data set pooled from contributors across Britain showed much greater variation in wing lengths, resulting from wider variation in the accuracy of measurement and recording. This variation in pooled data can have implications for analyses, and we discuss the importance of data quality in ringing schemes.
{"title":"Understanding potential sources of bias and error in the biometric sexing of birds","authors":"R. Broughton, J. Clark","doi":"10.1080/03078698.2017.1438367","DOIUrl":"https://doi.org/10.1080/03078698.2017.1438367","url":null,"abstract":"ABSTRACT Biometrics, particularly wing length, are commonly used to assign the sex of many birds in species where the plumage is similar for males and females. Virtually all species show some measurement overlap between the sexes, however, and measurement error can add further uncertainty into data sets. This can result in individuals being misclassified as the wrong sex and introducing bias into subsequent analyses, particularly if the life histories of misclassified birds differ from those of others. We used the Marsh Tit Poecile palustris as a case study to examine potential sources of error and bias when assigning sex based on wing length. There was no evidence for a heritability of wing lengths that could result in localised populations of atypical size via a ‘founder effect’, which would otherwise undermine biometric sexing. Additionally, potentially misclassified birds did not differ from others in how long they persisted in the local population, so avoiding any potential bias of misclassification in demographic analyses. Compared to Marsh Tit data collected during intensive studies, the national data set pooled from contributors across Britain showed much greater variation in wing lengths, resulting from wider variation in the accuracy of measurement and recording. This variation in pooled data can have implications for analyses, and we discuss the importance of data quality in ringing schemes.","PeriodicalId":35936,"journal":{"name":"Ringing and Migration","volume":"32 1","pages":"79 - 86"},"PeriodicalIF":0.0,"publicationDate":"2017-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/03078698.2017.1438367","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43696037","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}
Pub Date : 2017-07-03DOI: 10.1080/03078698.2017.1426924
W. H. Scott
ABSTRACT Reports from ringing groups received by the BTO are housed in the Chris Mead Library in Thetford. They are available to BTO members and may contain papers and reports of interest to ringers. Recently received reports are abstracted here.
{"title":"Papers from Ringing Group reports","authors":"W. H. Scott","doi":"10.1080/03078698.2017.1426924","DOIUrl":"https://doi.org/10.1080/03078698.2017.1426924","url":null,"abstract":"ABSTRACT Reports from ringing groups received by the BTO are housed in the Chris Mead Library in Thetford. They are available to BTO members and may contain papers and reports of interest to ringers. Recently received reports are abstracted here.","PeriodicalId":35936,"journal":{"name":"Ringing and Migration","volume":"32 1","pages":"110 - 110"},"PeriodicalIF":0.0,"publicationDate":"2017-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/03078698.2017.1426924","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49238014","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}
Pub Date : 2017-07-03DOI: 10.1080/03078698.2017.1437889
J. Laesser, Rien E. van Wijk
ABSTRACT In most bird species, all feathers are moulted at least once per year, usually after breeding (complete post-breeding moult). Woodpeckers (Picidae) often retain some primary coverts and secondaries during their otherwise complete post-breeding moult. To date, this phenomenon has received little attention and has not been studied thoroughly in European woodpeckers, even though it could prove very helpful for ageing and therefore for demographic studies. We studied the moult patterns of breeding adult Wrynecks Jynx torquilla in a Swiss Alpine valley between 2013 and 2016. Due to intensive ringing in the study area prior to the current study, our data set included birds of known age. Some individuals were captured and their moult documented in up to four years in a row. We found that Wrynecks present an extreme case of delayed primary-covert moult. No primary covert (PC) was renewed during the post-juvenile moult. At most three PCs were renewed by the second post-breeding moult and three to six at more advanced ages. That some juvenile PCs were retained until the sixth calendar year has not previously been documented for a species with such a relatively short lifespan. This principle of ‘postponed moult’ in Wrynecks affects the appearance of the PCs differently in each age class and allows us to age birds more accurately than previous methods. Here we describe how to interpret the moult pattern of PCs to age Wrynecks properly and argue that the moult strategy of Wrynecks was hitherto incompletely and in many cases mistakenly understood, leading to confusion in the ageing of Wrynecks.
{"title":"Postponed moult of primary coverts untangles the ageing of Wrynecks Jynx torquilla","authors":"J. Laesser, Rien E. van Wijk","doi":"10.1080/03078698.2017.1437889","DOIUrl":"https://doi.org/10.1080/03078698.2017.1437889","url":null,"abstract":"ABSTRACT In most bird species, all feathers are moulted at least once per year, usually after breeding (complete post-breeding moult). Woodpeckers (Picidae) often retain some primary coverts and secondaries during their otherwise complete post-breeding moult. To date, this phenomenon has received little attention and has not been studied thoroughly in European woodpeckers, even though it could prove very helpful for ageing and therefore for demographic studies. We studied the moult patterns of breeding adult Wrynecks Jynx torquilla in a Swiss Alpine valley between 2013 and 2016. Due to intensive ringing in the study area prior to the current study, our data set included birds of known age. Some individuals were captured and their moult documented in up to four years in a row. We found that Wrynecks present an extreme case of delayed primary-covert moult. No primary covert (PC) was renewed during the post-juvenile moult. At most three PCs were renewed by the second post-breeding moult and three to six at more advanced ages. That some juvenile PCs were retained until the sixth calendar year has not previously been documented for a species with such a relatively short lifespan. This principle of ‘postponed moult’ in Wrynecks affects the appearance of the PCs differently in each age class and allows us to age birds more accurately than previous methods. Here we describe how to interpret the moult pattern of PCs to age Wrynecks properly and argue that the moult strategy of Wrynecks was hitherto incompletely and in many cases mistakenly understood, leading to confusion in the ageing of Wrynecks.","PeriodicalId":35936,"journal":{"name":"Ringing and Migration","volume":"32 1","pages":"103 - 87"},"PeriodicalIF":0.0,"publicationDate":"2017-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/03078698.2017.1437889","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41522368","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}
Pub Date : 2017-01-02DOI: 10.1080/03078698.2017.1332299
M. Giammarino, P. Quatto
ABSTRACT We propose a functional data analysis (FDA) approach based on capture–recapture data to fit growth curves to wild Mallard Anas platyrhynchos. For this purpose, growth curves are provided from weight measurements through smoothing based on a suitable expansion in terms of B-splines. In dealing with wild young birds the unknown date of hatching and the small number of recaptures represent challenging problems. Our results suggest that the size at fledging of wild Mallards is not the adult size; the adult weight is reached at 70–80 days. We have not noted weight losses in fledging young and so the metabolic cost of fledging does not seem to be high. Our statistical approach offers a valid way to quantify the growth of precocial birds.
{"title":"Growth curves of wild Mallard, based on functional analysis of capture–recapture data","authors":"M. Giammarino, P. Quatto","doi":"10.1080/03078698.2017.1332299","DOIUrl":"https://doi.org/10.1080/03078698.2017.1332299","url":null,"abstract":"ABSTRACT We propose a functional data analysis (FDA) approach based on capture–recapture data to fit growth curves to wild Mallard Anas platyrhynchos. For this purpose, growth curves are provided from weight measurements through smoothing based on a suitable expansion in terms of B-splines. In dealing with wild young birds the unknown date of hatching and the small number of recaptures represent challenging problems. Our results suggest that the size at fledging of wild Mallards is not the adult size; the adult weight is reached at 70–80 days. We have not noted weight losses in fledging young and so the metabolic cost of fledging does not seem to be high. Our statistical approach offers a valid way to quantify the growth of precocial birds.","PeriodicalId":35936,"journal":{"name":"Ringing and Migration","volume":"32 1","pages":"37 - 42"},"PeriodicalIF":0.0,"publicationDate":"2017-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/03078698.2017.1332299","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47929606","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}
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