Pub Date : 2020-10-12DOI: 10.13157/arla.68.1.2021.sc1
G. Aleix-Mata, Jesús M. Pérez, B. Adrados, M. Boos, Evelyn Marty, Pierre Mourieres, Estelle Lauer, Sébastien Zimmermann, Marc Mossoll-Torres, Antonio Sánchez
In most unisexual species, the numbers of male and female individuals are approximately equal. The adult sex ratio (ASR) is a key demographic parameter for the conservation and management of wild species. However, in the case of monomorphic birds such as the Rock Ptarmigan Lagopus muta, estimating the sex ratio is difficult. To test if the sex ratio is balanced, we analysed the adult sex ratio of this tetraonid with two different methods, using microsatellite individualisation of non-invasive samples (faeces) and the hunting bag data of birds hunted in the French Alps and Pyrenees. The results of our non-invasive study revealed a balanced ASR in spring, whereas hunted specimens had a strongly male-biased ratio for adults but an approximately balanced sex ratio for juveniles (< 1 year old). The sex ratio estimated from hunting data may be biased for the adult population and, as occurs in other species, is not representative of the overall sex ratio. Our results suggest that, assuming our sampling strategy was adequate, non-invasive sampling is a good method to estimate ASR.—Aleix-Mata, G., Perez, J.M., Adrados, B., Boos, M., Marty, E., Mourieres, P., Lauer, E., Zimmermann, S., Mossoll-Torres, M. & Sanchez, A. (2021). Sex ratio of Alpine and Pyrenean Rock Ptarmigans Lagopus muta estimated by a non-invasive method (faecal DNA analysis) and from hunting bag data. Ardeola, 68: 201-212.
{"title":"Sex Ratio of Alpine and Pyrenean Rock Ptarmigans Lagopus muta Estimated by a Non-Invasive Method (Faecal DNA Analysis) and from Hunting Bag Data","authors":"G. Aleix-Mata, Jesús M. Pérez, B. Adrados, M. Boos, Evelyn Marty, Pierre Mourieres, Estelle Lauer, Sébastien Zimmermann, Marc Mossoll-Torres, Antonio Sánchez","doi":"10.13157/arla.68.1.2021.sc1","DOIUrl":"https://doi.org/10.13157/arla.68.1.2021.sc1","url":null,"abstract":"In most unisexual species, the numbers of male and female individuals are approximately equal. The adult sex ratio (ASR) is a key demographic parameter for the conservation and management of wild species. However, in the case of monomorphic birds such as the Rock Ptarmigan Lagopus muta, estimating the sex ratio is difficult. To test if the sex ratio is balanced, we analysed the adult sex ratio of this tetraonid with two different methods, using microsatellite individualisation of non-invasive samples (faeces) and the hunting bag data of birds hunted in the French Alps and Pyrenees. The results of our non-invasive study revealed a balanced ASR in spring, whereas hunted specimens had a strongly male-biased ratio for adults but an approximately balanced sex ratio for juveniles (< 1 year old). The sex ratio estimated from hunting data may be biased for the adult population and, as occurs in other species, is not representative of the overall sex ratio. Our results suggest that, assuming our sampling strategy was adequate, non-invasive sampling is a good method to estimate ASR.—Aleix-Mata, G., Perez, J.M., Adrados, B., Boos, M., Marty, E., Mourieres, P., Lauer, E., Zimmermann, S., Mossoll-Torres, M. & Sanchez, A. (2021). Sex ratio of Alpine and Pyrenean Rock Ptarmigans Lagopus muta estimated by a non-invasive method (faecal DNA analysis) and from hunting bag data. Ardeola, 68: 201-212.","PeriodicalId":55571,"journal":{"name":"Ardeola-International Journal of Ornithology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76476787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-12DOI: 10.13157/arla.68.1.2021.ra9
Daniel Parejo-Pulido, S. Magallanes, Celia Vinagre-Izquierdo, Juliana Valencia, C. Cruz, A. Marzal
{"title":"Relationships between Haemosporidian Infection and Parental Care in a Cooperative Breeder, the Iberian Magpie Cyanopica cooki","authors":"Daniel Parejo-Pulido, S. Magallanes, Celia Vinagre-Izquierdo, Juliana Valencia, C. Cruz, A. Marzal","doi":"10.13157/arla.68.1.2021.ra9","DOIUrl":"https://doi.org/10.13157/arla.68.1.2021.ra9","url":null,"abstract":"","PeriodicalId":55571,"journal":{"name":"Ardeola-International Journal of Ornithology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80495110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-12DOI: 10.13157/arla.68.1.2021.ra7
C. Novoa, J. Resseguier, B. Muffat-Joly, J. Casadesús, Marc Arvin-Bérod, J. Moya, Jean-François Desmet
Knowledge of natal dispersal and juvenile survival from parental independence until recruitment into breeding populations is an important aspect of population dynamics studies. Dispersal allows genetic connectivity and demographic compensation between neighbouring populations. These issues are particularly significant for species confined to mountaintops, as is the Rock Ptarmigan Lagopus muta in southern Europe. We studied natal dispersal and survival in juvenile Rock Ptarmigan in the French Alps and Pyrenees between 1999 and 2018 by radiotracking 113 young captured in September in two study areas. At both sites natal dispersal occurred in two discrete phases, in autumn (October-November) and in spring (late March-mid-May). Juvenile females dispersed twice as far as males in autumn at both sites but this difference decreased in spring and was not significant. Juveniles of both sexes dispersed further in the Pyrenees than in the Alps (males: 3.5 vs. 1.4km; females: 6.5 vs. 4.4km), a situation we attribute more to genetic differences between the two populations rather than to environmental factors. As to geographical barriers to dispersal, our radiotracking data along with extensive visual observations suggest that Rock Ptarmigan living in the Alps and the Pyrenees rarely fly across valleys 10-12km wide. For sexes and locations combined, the survival rate of juvenile Rock Ptarmigan during a ten-month period (September to June) was 0.636 (95%CI: 0.551-0.734). Long-distance dispersal tended to reduce the survival of birds during their first breeding attempt (April-June), a result that suggests a delayed effect of such dispersal.—Novoa, C., Resseguier, J., Muffat-Joly, B., Blanch Casadesus, J., Arvin-Berod, M., Gracia Moya, J. & Desmet, J.F. (2021). Natal dispersal and survival of juvenile Rock Ptarmigan Lagopus muta in the French Alps and Pyrenees. Ardeola, 68: 123-141.
{"title":"Natal Dispersal and Survival of Juvenile Rock Ptarmigan Lagopus Muta in the French Alps and Pyrenees","authors":"C. Novoa, J. Resseguier, B. Muffat-Joly, J. Casadesús, Marc Arvin-Bérod, J. Moya, Jean-François Desmet","doi":"10.13157/arla.68.1.2021.ra7","DOIUrl":"https://doi.org/10.13157/arla.68.1.2021.ra7","url":null,"abstract":"Knowledge of natal dispersal and juvenile survival from parental independence until recruitment into breeding populations is an important aspect of population dynamics studies. Dispersal allows genetic connectivity and demographic compensation between neighbouring populations. These issues are particularly significant for species confined to mountaintops, as is the Rock Ptarmigan Lagopus muta in southern Europe. We studied natal dispersal and survival in juvenile Rock Ptarmigan in the French Alps and Pyrenees between 1999 and 2018 by radiotracking 113 young captured in September in two study areas. At both sites natal dispersal occurred in two discrete phases, in autumn (October-November) and in spring (late March-mid-May). Juvenile females dispersed twice as far as males in autumn at both sites but this difference decreased in spring and was not significant. Juveniles of both sexes dispersed further in the Pyrenees than in the Alps (males: 3.5 vs. 1.4km; females: 6.5 vs. 4.4km), a situation we attribute more to genetic differences between the two populations rather than to environmental factors. As to geographical barriers to dispersal, our radiotracking data along with extensive visual observations suggest that Rock Ptarmigan living in the Alps and the Pyrenees rarely fly across valleys 10-12km wide. For sexes and locations combined, the survival rate of juvenile Rock Ptarmigan during a ten-month period (September to June) was 0.636 (95%CI: 0.551-0.734). Long-distance dispersal tended to reduce the survival of birds during their first breeding attempt (April-June), a result that suggests a delayed effect of such dispersal.—Novoa, C., Resseguier, J., Muffat-Joly, B., Blanch Casadesus, J., Arvin-Berod, M., Gracia Moya, J. & Desmet, J.F. (2021). Natal dispersal and survival of juvenile Rock Ptarmigan Lagopus muta in the French Alps and Pyrenees. Ardeola, 68: 123-141.","PeriodicalId":55571,"journal":{"name":"Ardeola-International Journal of Ornithology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78700971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-12DOI: 10.13157/arla.68.1.2021.ra6
Francesc Cuscó, G. Bota, Alba Llovet, S. Mañosa
In 2010-2016, we monitored 28 clutches of eight adult Little Bustard Tetrax tetrax females tracked by GPS on the Lleida Plain, in the Ebro Depression (NE Spain), to study nesting and incubation behaviour. In addition to describing these behaviours, we used generalised linear mixed models to identify the factors that determine hatching probability, such as laying date, nesting habitat and incubation behaviour. We found a high capacity (53%) to produce replacement clutches following nest failure. Unsuccessful nests represented 67.9% of clutches, mainly due to the low hatching rate of replacement clutches (16.7%) but also of the first clutches (44%). The main causes of failure were nest abandonment or predation (58%), while farming practices were responsible for 38.9% of failures. We found an increased risk of failure due to desertion or predation towards the end of the incubation. The risk of failure was higher in late clutches, although this seemed to be directly related to cereal mowing and to changes in nesting substrate, from cereal to alfalfa, which occurred throughout the breeding season. Likewise, we found a negative effect of the size of the field where the nest was found and of the surrounding habitat on the hatching probability, which we related to the availability of food for the female in these fields. Measures aimed at improving food provision, by increasing field edge density and fallow availability, would help to maintain hens in good condition prior to and during incubation, as well as providing suitable habitat for replacement clutches. Adaptive irrigation and mowing patterns in alfalfa fields during the nesting season could contribute to increasing the hatching success of replacement clutches.—Cusco, F., Bota, G., Llovet, A. & Manosa, S. (2021). Nesting and incubation behaviour of the Little Bustard Tetrax tetrax and its relation to hatching success. Ardeola, 68: 95-122.
{"title":"Nesting and Incubation Behaviour of the Little Bustard Tetrax tetrax and Its Relation to Hatching Success","authors":"Francesc Cuscó, G. Bota, Alba Llovet, S. Mañosa","doi":"10.13157/arla.68.1.2021.ra6","DOIUrl":"https://doi.org/10.13157/arla.68.1.2021.ra6","url":null,"abstract":"In 2010-2016, we monitored 28 clutches of eight adult Little Bustard Tetrax tetrax females tracked by GPS on the Lleida Plain, in the Ebro Depression (NE Spain), to study nesting and incubation behaviour. In addition to describing these behaviours, we used generalised linear mixed models to identify the factors that determine hatching probability, such as laying date, nesting habitat and incubation behaviour. We found a high capacity (53%) to produce replacement clutches following nest failure. Unsuccessful nests represented 67.9% of clutches, mainly due to the low hatching rate of replacement clutches (16.7%) but also of the first clutches (44%). The main causes of failure were nest abandonment or predation (58%), while farming practices were responsible for 38.9% of failures. We found an increased risk of failure due to desertion or predation towards the end of the incubation. The risk of failure was higher in late clutches, although this seemed to be directly related to cereal mowing and to changes in nesting substrate, from cereal to alfalfa, which occurred throughout the breeding season. Likewise, we found a negative effect of the size of the field where the nest was found and of the surrounding habitat on the hatching probability, which we related to the availability of food for the female in these fields. Measures aimed at improving food provision, by increasing field edge density and fallow availability, would help to maintain hens in good condition prior to and during incubation, as well as providing suitable habitat for replacement clutches. Adaptive irrigation and mowing patterns in alfalfa fields during the nesting season could contribute to increasing the hatching success of replacement clutches.—Cusco, F., Bota, G., Llovet, A. & Manosa, S. (2021). Nesting and incubation behaviour of the Little Bustard Tetrax tetrax and its relation to hatching success. Ardeola, 68: 95-122.","PeriodicalId":55571,"journal":{"name":"Ardeola-International Journal of Ornithology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83458995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-01DOI: 10.13157/arla.68.1.2021.ra10
J. Crespo, I. Solís, E. Barba
The illegal killing of many threatened species is an ongoing conservation concern, especially in the Mediterranean region. This study provides quantitative data on non-game birds admitted with gunshot injuries to wildlife rehabilitation centres (WRC) of the Valencian Community (eastern Spain), over a 25-year period (1991-2015). A total of 2,076 shot non-game birds of 101 different species were admitted, including 112 individuals belonging to 17 threatened species. Raptors were the most affected group, comprising 74% of the total admissions. The number of yearly admissions was positively related to the number of issued hunting licences, and both declined over the study period. Evidently, illegal hunting occurred throughout the year, although it peaked during the official hunting season. The occurrence of birds admitted with gunshot wounds was higher in more densely populated municipalities and in those closer to WRCs. Our results show that illegal hunting of protected bird species prevails despite legislative efforts, and it could pose a major problem for some endangered species. Accordingly, it is necessary to focus current action to reduce illegal hunting in conflictive areas.—Crespo, J., Solis, I. & Barba, E. (2021). Illegal bird hunting in eastern Spain: a declining trend, but still worrying. Ardeola, 68: 181-192.
{"title":"Illegal Bird Hunting in Eastern Spain: A Declining Trend, But Still Worrying","authors":"J. Crespo, I. Solís, E. Barba","doi":"10.13157/arla.68.1.2021.ra10","DOIUrl":"https://doi.org/10.13157/arla.68.1.2021.ra10","url":null,"abstract":"The illegal killing of many threatened species is an ongoing conservation concern, especially in the Mediterranean region. This study provides quantitative data on non-game birds admitted with gunshot injuries to wildlife rehabilitation centres (WRC) of the Valencian Community (eastern Spain), over a 25-year period (1991-2015). A total of 2,076 shot non-game birds of 101 different species were admitted, including 112 individuals belonging to 17 threatened species. Raptors were the most affected group, comprising 74% of the total admissions. The number of yearly admissions was positively related to the number of issued hunting licences, and both declined over the study period. Evidently, illegal hunting occurred throughout the year, although it peaked during the official hunting season. The occurrence of birds admitted with gunshot wounds was higher in more densely populated municipalities and in those closer to WRCs. Our results show that illegal hunting of protected bird species prevails despite legislative efforts, and it could pose a major problem for some endangered species. Accordingly, it is necessary to focus current action to reduce illegal hunting in conflictive areas.—Crespo, J., Solis, I. & Barba, E. (2021). Illegal bird hunting in eastern Spain: a declining trend, but still worrying. Ardeola, 68: 181-192.","PeriodicalId":55571,"journal":{"name":"Ardeola-International Journal of Ornithology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75323008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-08-14DOI: 10.13157/arla.68.1.2021.ra4
Cristina Vallino, E. Caprio, Fabrizio Genco, D. Chamberlain, C. Palestrini, A. Roggero, M. Bocca, A. Rolando
Summary. Mountain ecosystems are subject to many pressures, including changes in land use, rising temperatures and increasing recreational activities. These factors may disrupt food webs, threatening the survival of organisms and, ultimately, ecosystem functioning. However, few studies focus on the trends of different groups joined by trophic links in alpine ecosystems. The Yellow-billed (Alpine) Chough, Pyrrhocorax graculus, a gregarious bird that moves in flocks, is an ideal target species within this framework since it has a grasshopper-based diet during the summer and may attend sites that are heavily developed for recreational activities. We tested therefore whether flock size co-varied with grasshopper abundance along an elevational gradient in two alpine areas subject to different levels of human disturbance. Chough flock size and grasshopper abundance were measured along elevational transects. The median flock size was analysed in relation to grasshopper abundance and biomass, we also conducted negative binomial GLMs to account for effects of period (i.e. from June to mid-August), site and elevation. In both study areas, chough flocks were larger at the elevation where grasshoppers were more abundant. This may indicate the capacity of the species to follow large-scale fluctuations in their key insect prey. On the other hand, the relationship between flock size and grasshopper biomass was positive at a natural site and negative at a tourist site. This suggests that where there is a high level of human influence, other factors, such as the availability of human-provided food, may disturb the natural relationship between choughs and their key prey. Overall, our results indicate that flocking by foraging Yellow-billed Choughs reflects both grasshopper abundance and the degree of anthropogenic influence.—Vallino, C., Caprio, E., Genco, F., Chamberlain, D., Palestrini, C., Roggero, A., Bocca, M. & Rolando, A. (2021). Flocking of foraging Yellow-billed Choughs Pyrrhocorax graculus reflects the availability of grasshoppers and the extent of human influence in high elevation ecosystems. Ardeola, 68: 53-70.
{"title":"Flocking of Foraging Yellow-Billed Choughs Pyrrhocorax Graculus Reflects the Availability of Grasshoppers and the Extent of Human Influence in High Elevation Ecosystems","authors":"Cristina Vallino, E. Caprio, Fabrizio Genco, D. Chamberlain, C. Palestrini, A. Roggero, M. Bocca, A. Rolando","doi":"10.13157/arla.68.1.2021.ra4","DOIUrl":"https://doi.org/10.13157/arla.68.1.2021.ra4","url":null,"abstract":"Summary. Mountain ecosystems are subject to many pressures, including changes in land use, rising temperatures and increasing recreational activities. These factors may disrupt food webs, threatening the survival of organisms and, ultimately, ecosystem functioning. However, few studies focus on the trends of different groups joined by trophic links in alpine ecosystems. The Yellow-billed (Alpine) Chough, Pyrrhocorax graculus, a gregarious bird that moves in flocks, is an ideal target species within this framework since it has a grasshopper-based diet during the summer and may attend sites that are heavily developed for recreational activities. We tested therefore whether flock size co-varied with grasshopper abundance along an elevational gradient in two alpine areas subject to different levels of human disturbance. Chough flock size and grasshopper abundance were measured along elevational transects. The median flock size was analysed in relation to grasshopper abundance and biomass, we also conducted negative binomial GLMs to account for effects of period (i.e. from June to mid-August), site and elevation. In both study areas, chough flocks were larger at the elevation where grasshoppers were more abundant. This may indicate the capacity of the species to follow large-scale fluctuations in their key insect prey. On the other hand, the relationship between flock size and grasshopper biomass was positive at a natural site and negative at a tourist site. This suggests that where there is a high level of human influence, other factors, such as the availability of human-provided food, may disturb the natural relationship between choughs and their key prey. Overall, our results indicate that flocking by foraging Yellow-billed Choughs reflects both grasshopper abundance and the degree of anthropogenic influence.—Vallino, C., Caprio, E., Genco, F., Chamberlain, D., Palestrini, C., Roggero, A., Bocca, M. & Rolando, A. (2021). Flocking of foraging Yellow-billed Choughs Pyrrhocorax graculus reflects the availability of grasshoppers and the extent of human influence in high elevation ecosystems. Ardeola, 68: 53-70.","PeriodicalId":55571,"journal":{"name":"Ardeola-International Journal of Ornithology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74074168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-08-14DOI: 10.13157/arla.68.1.2021.ra3
L. Carrascal, J. C. Del Moral
Summary. Extensive bird monitoring programmes are fundamental for estimating inter-annual population trends using data provided by thousands of observers through standardised fieldwork. Gordo (2018) has proposed that abundance data recorded by common bird monitoring schemes (e.g. SACRE programme) should be used cautiously due to its potential inaccuracy, because two surveys per spring are not enough to record the actual maximum number of individual birds at a sampling location. We carried out numerical simulations and analysed the interspecific pattern of statistical significance of the published population trends of the Spanish common birds census, the SACRE programme (1998-2011), in order to test how the number of repetitions of censuses per year affects the power of tests: (i.e. the probability of detecting significant trends that are in fact true), and the probability of obtaining low false discovery rates: i.e. identifying significant changes that are actually false, when estimating yearly population changes. We agree with Gordo (2018) that two surveys of the same sampling stations per year are unable to detect the maximum number of birds throughout a breeding season. Nevertheless, the goal of monitoring programmes is not to obtain the maximum number of birds at each sampling unit over a long time span but to measure reliable population trends. Our results demonstrate that the average number of birds recorded in two surveys per season provides a highly reliable indication of population trends for abundant and widely distributed bird species, the focal taxa in common birds monitoring schemes, especially of long-term average trends > ±2.5% change annually. The actual population trends for very rare species, such as those with data from fewer than 50 UTM squares and < 5 individual birds per census and UTM cell, are hard to detect unless they show yearly percentage population changes greater than ±5%.—Carrascal, L.M. & del Moral, J.C. (2021). Two surveys per spring are enough to obtain robust population trends of common and widespread birds in yearly monitoring programmes. Ardeola, 68: 33-51.
总结。广泛的鸟类监测计划是利用数千名观察员通过标准化实地调查提供的数据估计年际种群趋势的基础。Gordo(2018)提出,由于常见鸟类监测计划(例如SACRE计划)记录的丰度数据可能不准确,因此应谨慎使用,因为每年春季两次调查不足以记录采样地点单个鸟类的实际最大数量。我们进行了数值模拟,并分析了西班牙常见鸟类普查(SACRE方案)公布的种群趋势的种间统计显著性模式(1998-2011年),以测试每年重复普查的次数如何影响测试的能力(即发现事实上是真实的重要趋势的概率),以及获得低错误发现率的概率:即,在估计年度人口变化时,识别出实际上是错误的重大变化。我们同意Gordo(2018)的观点,即每年对同一采样站进行两次调查无法检测到整个繁殖季节鸟类的最大数量。然而,监测方案的目标不是在很长一段时间内获得每个取样单位的最大鸟类数量,而是衡量可靠的种群趋势。研究结果表明,对于数量丰富且分布广泛的鸟类(常见鸟类监测方案的重点类群),每季度两次调查记录的平均鸟类数量可以高度可靠地反映种群趋势,特别是长期平均趋势的年变化>±2.5%。非常稀有物种的实际种群趋势,如每次普查和UTM细胞的数据少于50个UTM平方和< 5只鸟,很难检测到,除非它们显示出每年的种群变化百分比大于±5%。——carrascal, L.M. & del Moral, J.C.(2021)。每年春季两次调查足以在年度监测计划中获得常见和广泛分布的鸟类的强劲种群趋势。农业学报,68:33-51。
{"title":"Two Surveys Per Spring Are Enough to Obtain Robust Population Trends of Common and Widespread Birds in Yearly Monitoring Programmes","authors":"L. Carrascal, J. C. Del Moral","doi":"10.13157/arla.68.1.2021.ra3","DOIUrl":"https://doi.org/10.13157/arla.68.1.2021.ra3","url":null,"abstract":"Summary. Extensive bird monitoring programmes are fundamental for estimating inter-annual population trends using data provided by thousands of observers through standardised fieldwork. Gordo (2018) has proposed that abundance data recorded by common bird monitoring schemes (e.g. SACRE programme) should be used cautiously due to its potential inaccuracy, because two surveys per spring are not enough to record the actual maximum number of individual birds at a sampling location. We carried out numerical simulations and analysed the interspecific pattern of statistical significance of the published population trends of the Spanish common birds census, the SACRE programme (1998-2011), in order to test how the number of repetitions of censuses per year affects the power of tests: (i.e. the probability of detecting significant trends that are in fact true), and the probability of obtaining low false discovery rates: i.e. identifying significant changes that are actually false, when estimating yearly population changes. We agree with Gordo (2018) that two surveys of the same sampling stations per year are unable to detect the maximum number of birds throughout a breeding season. Nevertheless, the goal of monitoring programmes is not to obtain the maximum number of birds at each sampling unit over a long time span but to measure reliable population trends. Our results demonstrate that the average number of birds recorded in two surveys per season provides a highly reliable indication of population trends for abundant and widely distributed bird species, the focal taxa in common birds monitoring schemes, especially of long-term average trends > ±2.5% change annually. The actual population trends for very rare species, such as those with data from fewer than 50 UTM squares and < 5 individual birds per census and UTM cell, are hard to detect unless they show yearly percentage population changes greater than ±5%.—Carrascal, L.M. & del Moral, J.C. (2021). Two surveys per spring are enough to obtain robust population trends of common and widespread birds in yearly monitoring programmes. Ardeola, 68: 33-51.","PeriodicalId":55571,"journal":{"name":"Ardeola-International Journal of Ornithology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84895353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-08-01DOI: 10.13157/arla.68.1.2021.ra5
Julia Gómez-Catasús, L. Carrascal, V. Moraleda, José Colsa, Fernando Garcés, C. Schuster
Carcass counts notably underestimate avian collision rates due to three main bias sources: imperfect detection, carcass removal by scavengers and carcass dispersion in unsearched areas. We assessed these sources of bias at electric lines of two Canary Islands, Lanzarote and Fuerteventura, quantifying the factors influencing them. We also carried out a cost-effectiveness assessment of carcass search done perpendicularly to electric line axis. We surveyed 230km of three types of electric lines (high-voltage, medium voltage and telephone lines) during three periods (July 2015, November-December 2015 and March 2016) searching for collision fatalities (N = 431), recording the species, the carcass distance from the electric line, mean cable height, carcass detection distance and decomposition state. In addition, we carried out a disappearance rate experiment to estimate carcass removal by scavengers. A generalised least squares model was used to analyse dispersion distance of carcass from electric lines, in relation to species body mass, mean cable height and line typology. Detection probability functions were fitted to estimate carcass detectability, incorporating body mass, decomposition state and habitat structure as covariates. A Generalised Mixed-Effects model was carried out to analyse carcass disappearance in relation to time elapsed since carcass placement, carcass size, season and island. Dispersion distance decreased with body mass and increased with cable height, being further at high-voltage lines. Overall, detection probability was 0.134, increasing with carcass size, decreasing with decomposition state and being lower in rocky areas which offered a significant challenge when walking through rough terrain. Disappearance rates differed between islands probably due to differences in avian scavenger abundance, increased with time elapsed and decreased with bird size. This study provides correction factors to obtain unbiased estimates of avian mortality rates within sparsely vegetated landscapes. Moreover, it identifies a 27m threshold distance at which the cost-effectiveness of searching for carcasses is optimised.—Gomez-Catasus, J., Carrascal, L.M., Moraleda, V., Colsa, J., Garces, F. & Schuster, C. (2021). Factors affecting differential underestimates of bird collision fatalities at electric lines: a case study in the Canary Islands. Ardeola, 68: 71-94.
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Pub Date : 2020-07-30DOI: 10.13157/arla.68.1.2021.ra2
J. Tellería, Guillermo Fandos, J. Fernández‐López
Summary. This paper explores how environmental traits shape the winter distribution of passerine (O. Passeriformes) richness in the south-western Palearctic, a major wintering ground for the European avifauna. We apply three complementary approaches. First, we assess the way climate, landscape and habitat affect species richness by means of field counts across the study area. Second, we model the spatial distribution of six common passerines using ring recoveries as presence data. Finally, where the resulting models predict the actual distribution of birds, we employ the models to forecast the future distribution of richness according to predictions of climate change, i.e. of increasing temperature and decreasing precipitation. The results support an effect of landscape, habitat structure, temperature and precipitation on bird richness. Distribution models fit the actual distribution of bird richness and their predictions suggest that winter species richness will decrease in lowlands and increase in highlands. This pattern could be related to direct effects of temperature on thermoregulatory costs and indirect effects on winter primary productivity affecting food resources. These results also indicate that, in a context of climate warming, species-rich sectors will shift from lowlands to highlands, suggesting that uplands will have a regulatory role in the future winter distribution of birds.—Tellería, J.L., Fandos, G. & Fernández-López, J. (2021). Winter bird richness distribution in the south-western Palearctic: current patterns and potential changes. Ardeola, 68: 17-32.
总结。本文探讨了环境特征如何塑造雀形鸟(O. passerformes)丰富度在古北大陆西南部的冬季分布,这是欧洲鸟类的主要越冬地。我们采用三种互补的方法。首先,我们通过野外统计的方法评估了气候、景观和栖息地对物种丰富度的影响。其次,我们使用环恢复作为存在数据对六种常见雀形目的空间分布进行了建模。最后,在模型预测鸟类实际分布的地方,我们利用模型根据气候变化(即温度升高和降水减少)预测未来丰富度的分布。研究结果支持景观、生境结构、温度和降水对鸟类丰富度的影响。分布模型与鸟类丰富度的实际分布相吻合,其预测结果表明,冬季鸟类丰富度在低地呈下降趋势,在高原呈上升趋势。这种模式可能与温度对温度调节成本的直接影响和对影响食物资源的冬季初级生产力的间接影响有关。这些结果还表明,在气候变暖的背景下,物种丰富的地区将从低地转移到高地,这表明高地将在未来冬季鸟类的分布中发挥调节作用。-Tellería, J.L, Fandos, G. & Fernández-López, J.(2021)。古北纬西南部冬季鸟类丰富度分布:当前模式和潜在变化。农业学报,68:17-32。
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Pub Date : 2020-07-14DOI: 10.13157/arla.68.1.2021.ra1
A. Rotger, A. Sola, G. Tavecchia, A. Sanz‐Aguilar
Summary. Identifying important foraging areas is fundamental to detecting the demographic drivers of a species and ultimately to plan conservation measures. For some species, such as small pelagic seabirds, foraging grounds are difficult to locate and remain largely unknown. We used miniaturised GPS devices (∼0.95g) to study foraging movements of Mediterranean Storm-petrels Hydrobates pelagicus melitensis during the incubation period. A total of 43 individuals at Benidorm colony (southwestern Mediterranean Sea) were tracked during a single foraging trip. We first assessed potential negative effects of the tracking devices. We recorded 22 complete foraging trips and measured home-range, foraging areas and the degree of overlap among individuals. We used first passage time analyses (FPT) to differentiate foraging/resting from flying/travelling activities and to infer potential foraging areas. All tracked birds returned to the colony. On average, individual body weight slightly decreased after foraging trips, suggesting a small immediate negative effect of the device. Tracked birds had high breeding success (0.71). Foraging trips lasted between 1 and 4.5 days with the total distance travelled ranging between 303.14 and 1,726.53km. The visited areas covered the whole south-western part of the Mediterranean Sea. Tracked individuals shared more than 50% of their home-range areas. Foraging areas were located further from the colony than previously thought (from 240 to 469km away) on deep sea areas of the Alboran Sea and Cartagena Canyons. Further studies are needed to locate foraging grounds during other life-cycle periods and to evaluate repeatability yearly, in order to determine the important marine areas for the species.—Rotger, A., Sola, A., Tavecchia, G. & Sanz-Aguilar, A. (2021). Foraging far from home: GPS-tracking of Mediterranean Storm-petrels Hydrobates pelagicus melitensis reveals long-distance foraging movements. Ardeola, 68: 3-16.
总结。确定重要的觅食区域是探测物种的人口驱动因素并最终制定保护措施的基础。对一些物种来说,比如小型远洋海鸟,觅食地很难定位,基本上不为人知。我们使用小型GPS设备(~ 0.95g)研究地中海风暴海燕在孵化期间的觅食运动。在贝尼多姆殖民地(地中海西南部)的一次觅食旅行中,总共追踪了43只个体。我们首先评估了跟踪设备的潜在负面影响。我们记录了22次完整的觅食行程,并测量了它们的家园范围、觅食区域和个体之间的重叠程度。我们使用首次通过时间分析(FPT)来区分觅食/休息与飞行/旅行活动,并推断潜在的觅食区域。所有被追踪到的鸟都回到了它们的栖息地。平均而言,在觅食旅行后,个体体重略有下降,这表明该设备的直接负面影响很小。追踪鸟的繁殖成功率较高(0.71)。觅食行程持续1 ~ 4.5天,总行程在303.14 ~ 1726.53公里之间。被访问的地区覆盖了整个地中海西南部。被追踪的个体共享超过50%的家园范围。觅食区域位于阿尔博兰海和卡塔赫纳峡谷的深海区域,比之前认为的距离殖民地更远(从240公里到469公里)。为了确定该物种的重要海洋区域,需要进一步的研究来确定其他生命周期时期的觅食地,并每年评估可重复性。——rotger, A, Sola, A, Tavecchia, G. & Sanz-Aguilar, A.(2021)。远离家乡的觅食:地中海风暴海燕的gps追踪揭示了远距离觅食的运动。阿尔迪奥拉,68:3-16。
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