Pub Date : 2021-10-02DOI: 10.1080/00063657.2022.2124954
D. Dementavičius, Saulius Rumbutis, Rimgaudas Treinys
ABSTRACT Capsule: We found no evidence of decreased reproductive performance of the White-tailed Eagle Haliaeetus albicilla, despite ongoing population increases in an environment characterized by different types of utilized habitats. Aim: To characterize temporal and spatial variations in several components of breeding performance in an increasing White-tailed Eagle population. Methods: The breeding performance and number of pairs located in the region east of the Baltic Sea was monitored between 2005 and 2020. We analysed the trends in the numbers of pairs and several reproduction parameters for 16 years, and compared variation in breeding performance in four different habitats through application of generalized linear (mixed) models. Results: The number of White-tailed Eagle pairs increased three-fold locally between 2005 and 2020, but we found no evidence for a deterioration in breeding performance parameters (nesting success, brood size, proportion of females among nestlings, body condition of nestlings). The probability of successful nesting, nestling sex and number of nestlings in a brood were found to be similar between pairs associated with different habitats, ranging from coastal lagoons to natural waterbodies within an inland landscape. The body condition of the nestlings, however, was habitat-dependent, with the best body condition evident in nestlings reared near the Curonian Lagoon. Conclusion: Results indicate that the abundance of this predator population will continue to grow in the region east of the Baltic Sea.
{"title":"Spatial and temporal variation in breeding performance in the increasing White-tailed Eagle Haliaeetus albicilla population to the east of the Baltic Sea","authors":"D. Dementavičius, Saulius Rumbutis, Rimgaudas Treinys","doi":"10.1080/00063657.2022.2124954","DOIUrl":"https://doi.org/10.1080/00063657.2022.2124954","url":null,"abstract":"ABSTRACT Capsule: We found no evidence of decreased reproductive performance of the White-tailed Eagle Haliaeetus albicilla, despite ongoing population increases in an environment characterized by different types of utilized habitats. Aim: To characterize temporal and spatial variations in several components of breeding performance in an increasing White-tailed Eagle population. Methods: The breeding performance and number of pairs located in the region east of the Baltic Sea was monitored between 2005 and 2020. We analysed the trends in the numbers of pairs and several reproduction parameters for 16 years, and compared variation in breeding performance in four different habitats through application of generalized linear (mixed) models. Results: The number of White-tailed Eagle pairs increased three-fold locally between 2005 and 2020, but we found no evidence for a deterioration in breeding performance parameters (nesting success, brood size, proportion of females among nestlings, body condition of nestlings). The probability of successful nesting, nestling sex and number of nestlings in a brood were found to be similar between pairs associated with different habitats, ranging from coastal lagoons to natural waterbodies within an inland landscape. The body condition of the nestlings, however, was habitat-dependent, with the best body condition evident in nestlings reared near the Curonian Lagoon. Conclusion: Results indicate that the abundance of this predator population will continue to grow in the region east of the Baltic Sea.","PeriodicalId":55353,"journal":{"name":"Bird Study","volume":"68 1","pages":"462 - 476"},"PeriodicalIF":0.7,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49208991","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 : 2021-10-02DOI: 10.1080/00063657.2022.2113855
D. Jarrett, J. Calladine, A. Cook, A. Upton, Jim Williams, Stuart Williams, Jared M. Wilson, Mark W. Wilson, Ian D. Woodward, E. Humphreys
ABSTRACT Capsule: Recording of behavioural responses to ferry traffic for 11 target species showed that Red-throated Diver Gavia stellata, Slavonian Grebe Podiceps auratus, and Black-throated Diver Gavia arctica were most likely to react to passing vessels. Aim: To provide information on how responses to marine traffic vary between waterbird species to inform marine spatial planning and environmental impact assessments in the near-shore environment. Methods: We recorded behavioural responses to ferry traffic for 11 target species in near-shore waters: Common Eider Somateria mollissima, Goldeneye Bucephala clangula, Long-tailed Duck Clangula hyemalis, Velvet Scoter Melanitta fusca, Red-breasted Merganser Mergus serrator, Black-throated Diver, Great Northern Diver Gavia immer, Red-throated Diver, European Shag Gulosus aristotelis, Slavonian Grebe and Black Guillemot Cepphus grylle. Responses were analysed using generalized linear models and mixed models. Results: Red-throated Diver, Black-throated Diver and Slavonian Grebe were the most likely species to exhibit a response to passing vessels. While Red-throated Divers and Slavonian Grebes were highly likely to flush, Black-throated Divers and Great Northern Divers rarely took flight, instead favouring swim or dive responses. In rougher sea conditions birds were more likely to take flight, and the propensity to respond declined across the wintering period. Conclusions: This research provides comparative evidence on the behavioural responses of waterbirds to marine traffic. The results support previous studies which highlighted the high sensitivity of diver species to disturbance and provide new evidence that Slavonian Grebe may also be a high sensitivity species.
{"title":"Behavioural responses of non-breeding waterbirds to marine traffic in the near-shore environment","authors":"D. Jarrett, J. Calladine, A. Cook, A. Upton, Jim Williams, Stuart Williams, Jared M. Wilson, Mark W. Wilson, Ian D. Woodward, E. Humphreys","doi":"10.1080/00063657.2022.2113855","DOIUrl":"https://doi.org/10.1080/00063657.2022.2113855","url":null,"abstract":"ABSTRACT Capsule: Recording of behavioural responses to ferry traffic for 11 target species showed that Red-throated Diver Gavia stellata, Slavonian Grebe Podiceps auratus, and Black-throated Diver Gavia arctica were most likely to react to passing vessels. Aim: To provide information on how responses to marine traffic vary between waterbird species to inform marine spatial planning and environmental impact assessments in the near-shore environment. Methods: We recorded behavioural responses to ferry traffic for 11 target species in near-shore waters: Common Eider Somateria mollissima, Goldeneye Bucephala clangula, Long-tailed Duck Clangula hyemalis, Velvet Scoter Melanitta fusca, Red-breasted Merganser Mergus serrator, Black-throated Diver, Great Northern Diver Gavia immer, Red-throated Diver, European Shag Gulosus aristotelis, Slavonian Grebe and Black Guillemot Cepphus grylle. Responses were analysed using generalized linear models and mixed models. Results: Red-throated Diver, Black-throated Diver and Slavonian Grebe were the most likely species to exhibit a response to passing vessels. While Red-throated Divers and Slavonian Grebes were highly likely to flush, Black-throated Divers and Great Northern Divers rarely took flight, instead favouring swim or dive responses. In rougher sea conditions birds were more likely to take flight, and the propensity to respond declined across the wintering period. Conclusions: This research provides comparative evidence on the behavioural responses of waterbirds to marine traffic. The results support previous studies which highlighted the high sensitivity of diver species to disturbance and provide new evidence that Slavonian Grebe may also be a high sensitivity species.","PeriodicalId":55353,"journal":{"name":"Bird Study","volume":"68 1","pages":"443 - 454"},"PeriodicalIF":0.7,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47255928","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 : 2021-10-02DOI: 10.1080/00063657.2022.2113856
D. Mazzoni, J. Pascual, L. Arroyo, T. Montalvo, J. González‐Solís, J. C. Senar
ABSTRACT Capsule: Previous observations in Barcelona and other cities showed that approximately 40% of the food ingested by adult Monk Parakeets Myiopsitta monachus is of anthropogenic origin. Here we show that this type of food source is also used for feeding nestlings. Aims: To quantify the proportion of anthropogenic food within the diet of nestling Monk Parakeets, a non-native species in Barcelona. Methods: We analysed stable isotopes of 13C and 15N in feathers of Monk Parakeet nestlings collected in the Barcelona city area. We also sampled potential food sources ingested by Monk Parakeets to reconstruct the nestling diet using Bayesian mixing models with MixSIAR. Results: Almost 30% of the nestlings’ diet was composed of anthropogenic food. Conclusions: Since food availability is a major factor regulating population growth, we propose educating the general public to reduce the food supply for the species and ultimately limit its population growth.
{"title":"The diet of Monk Parakeet Myiopsitta monachus nestlings in an urban area: a study using stable isotopes","authors":"D. Mazzoni, J. Pascual, L. Arroyo, T. Montalvo, J. González‐Solís, J. C. Senar","doi":"10.1080/00063657.2022.2113856","DOIUrl":"https://doi.org/10.1080/00063657.2022.2113856","url":null,"abstract":"ABSTRACT Capsule: Previous observations in Barcelona and other cities showed that approximately 40% of the food ingested by adult Monk Parakeets Myiopsitta monachus is of anthropogenic origin. Here we show that this type of food source is also used for feeding nestlings. Aims: To quantify the proportion of anthropogenic food within the diet of nestling Monk Parakeets, a non-native species in Barcelona. Methods: We analysed stable isotopes of 13C and 15N in feathers of Monk Parakeet nestlings collected in the Barcelona city area. We also sampled potential food sources ingested by Monk Parakeets to reconstruct the nestling diet using Bayesian mixing models with MixSIAR. Results: Almost 30% of the nestlings’ diet was composed of anthropogenic food. Conclusions: Since food availability is a major factor regulating population growth, we propose educating the general public to reduce the food supply for the species and ultimately limit its population growth.","PeriodicalId":55353,"journal":{"name":"Bird Study","volume":"68 1","pages":"455 - 461"},"PeriodicalIF":0.7,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42968564","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 : 2021-07-03DOI: 10.1080/00063657.2022.2103514
S. P. Campbell, Michael E. Akresh, Neil A. Gifford, David I. King
ABSTRACT Capsule In a single-year study, attaching geolocators to male Prairie Warblers Setophaga discolor, one of the smallest species to date to carry geolocators, decreased return rates but had no effect on inter-annual territory fidelity. Aims To examine the effects of light-level geolocators on return rates and inter-annual territory fidelity of adult, male Prairie Warblers migrating to and from their non-breeding grounds. Methods During the 2016 breeding season we captured adult male Prairie Warblers at two sites in northeastern USA and attached geolocators and colour rings to one group of birds, and only colour rings to another group of birds. During the 2017 breeding season, we estimated return rates to the sites and inter-annual territory fidelity (i.e. distance between territory locations from one year to the next) for the birds that returned to the sites. We compared return rates and territory fidelity between birds with and without geolocators. Results Geolocators significantly decreased return rates of male Prairie Warblers to the study sites by 0.18 (95% credible interval [CI]: −0.37 to 0.01) from 2016 to 2017. Birds that returned exhibited a range of distances between estimated locations of territories in each year (7–2104 m), but the differences in distances between birds with and without geolocators were not statistically significant. Conclusion Although return rates were lower for Prairie Warblers with geolocators, these effects should not necessarily disqualify their use. Rather, the magnitude of the negative effects on individuals needs to be considered against the benefits and reliability of the information gained for the population or species. We recommend the effects of geolocators and other tracking tags should be studied and reported in conjunction with the main objectives of the study for which the tags are being used.
{"title":"Effects of light-level geolocators on return rates and inter-annual territory fidelity of Prairie Warblers Setophaga discolor","authors":"S. P. Campbell, Michael E. Akresh, Neil A. Gifford, David I. King","doi":"10.1080/00063657.2022.2103514","DOIUrl":"https://doi.org/10.1080/00063657.2022.2103514","url":null,"abstract":"ABSTRACT Capsule In a single-year study, attaching geolocators to male Prairie Warblers Setophaga discolor, one of the smallest species to date to carry geolocators, decreased return rates but had no effect on inter-annual territory fidelity. Aims To examine the effects of light-level geolocators on return rates and inter-annual territory fidelity of adult, male Prairie Warblers migrating to and from their non-breeding grounds. Methods During the 2016 breeding season we captured adult male Prairie Warblers at two sites in northeastern USA and attached geolocators and colour rings to one group of birds, and only colour rings to another group of birds. During the 2017 breeding season, we estimated return rates to the sites and inter-annual territory fidelity (i.e. distance between territory locations from one year to the next) for the birds that returned to the sites. We compared return rates and territory fidelity between birds with and without geolocators. Results Geolocators significantly decreased return rates of male Prairie Warblers to the study sites by 0.18 (95% credible interval [CI]: −0.37 to 0.01) from 2016 to 2017. Birds that returned exhibited a range of distances between estimated locations of territories in each year (7–2104 m), but the differences in distances between birds with and without geolocators were not statistically significant. Conclusion Although return rates were lower for Prairie Warblers with geolocators, these effects should not necessarily disqualify their use. Rather, the magnitude of the negative effects on individuals needs to be considered against the benefits and reliability of the information gained for the population or species. We recommend the effects of geolocators and other tracking tags should be studied and reported in conjunction with the main objectives of the study for which the tags are being used.","PeriodicalId":55353,"journal":{"name":"Bird Study","volume":"68 1","pages":"396 - 407"},"PeriodicalIF":0.7,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45588596","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 : 2021-07-03DOI: 10.1080/00063657.2022.2103515
Alan McCarthy, P. Smiddy, T. Nagle, A. Mee, S. Irwin, Anthony Caravaggi, J. O’Halloran
ABSTRACT Capsule Habitat composition plays a key role in determining the winter diet of the Hen Harrier Circus cyaneus, which varies across the winter season and between years. Aims To determine the winter diet of the Hen Harrier and examine temporal and spatial variations in diet composition. Methods A total of 1117 Hen Harrier pellets were collected from 11 winter roosts between 2017 and 2021 in Ireland. Results Hen Harrier winter diet was dominated by avian prey (95.9% of pellets), with mammalian prey found in 12.0% of pellets. The occurrence of small birds and small mammals in the diet was positively associated with the proportion of arable, wild bird cover, and low-intensity agriculture around the roost sites. The frequency of medium-sized birds (primarily Redwing Turdus iliacus and Common Snipe Gallinago gallinago) in the diet was positively associated with the proportion of bog and young conifer forests surrounding roost sites. Diet varied across regions, with pellets from roosts in lowland coastal areas having a greater prevalence of small birds and small mammals, and pellets from roosts in upland areas having a greater prevalence of medium-sized birds. The proportion of medium-sized birds in the diet changed across months, with that of small birds and small mammals remaining stable. There was also variation between winters in the proportion of small- and medium-sized birds in the diet. Conclusions Habitat, along with region and time, are important drivers of variation in Hen Harrier diet. Our findings highlight the opportunity for the enhancement of Hen Harrier habitat through land management, and can be used to inform effective conservation strategies for wintering Hen Harriers at a landscape scale.
{"title":"Landscape and temporal influences on the winter diet of a threatened diurnal raptor, the Hen Harrier Circus cyaneus","authors":"Alan McCarthy, P. Smiddy, T. Nagle, A. Mee, S. Irwin, Anthony Caravaggi, J. O’Halloran","doi":"10.1080/00063657.2022.2103515","DOIUrl":"https://doi.org/10.1080/00063657.2022.2103515","url":null,"abstract":"ABSTRACT Capsule Habitat composition plays a key role in determining the winter diet of the Hen Harrier Circus cyaneus, which varies across the winter season and between years. Aims To determine the winter diet of the Hen Harrier and examine temporal and spatial variations in diet composition. Methods A total of 1117 Hen Harrier pellets were collected from 11 winter roosts between 2017 and 2021 in Ireland. Results Hen Harrier winter diet was dominated by avian prey (95.9% of pellets), with mammalian prey found in 12.0% of pellets. The occurrence of small birds and small mammals in the diet was positively associated with the proportion of arable, wild bird cover, and low-intensity agriculture around the roost sites. The frequency of medium-sized birds (primarily Redwing Turdus iliacus and Common Snipe Gallinago gallinago) in the diet was positively associated with the proportion of bog and young conifer forests surrounding roost sites. Diet varied across regions, with pellets from roosts in lowland coastal areas having a greater prevalence of small birds and small mammals, and pellets from roosts in upland areas having a greater prevalence of medium-sized birds. The proportion of medium-sized birds in the diet changed across months, with that of small birds and small mammals remaining stable. There was also variation between winters in the proportion of small- and medium-sized birds in the diet. Conclusions Habitat, along with region and time, are important drivers of variation in Hen Harrier diet. Our findings highlight the opportunity for the enhancement of Hen Harrier habitat through land management, and can be used to inform effective conservation strategies for wintering Hen Harriers at a landscape scale.","PeriodicalId":55353,"journal":{"name":"Bird Study","volume":"68 1","pages":"408 - 421"},"PeriodicalIF":0.7,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47105963","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 : 2021-07-03DOI: 10.1080/00063657.2022.2096874
R. Valle, A. Baaloudj, F. Scarton
ABSTRACT This study describes a new method for counting breeding Purple Herons Ardea purpurea on a large wetland complex (Po Delta, Italy) using Google Earth satellite imagery in comparison to traditional ground counts in 2017. Google Earth counts provide an accurate, rapid, and inexpensive method for estimating the breeding population of Purple Herons, both saving time and increasing count accuracy in comparison to ground counts.
{"title":"A new method for surveying Purple Heron Ardea purpurea colonies using Google Earth","authors":"R. Valle, A. Baaloudj, F. Scarton","doi":"10.1080/00063657.2022.2096874","DOIUrl":"https://doi.org/10.1080/00063657.2022.2096874","url":null,"abstract":"ABSTRACT This study describes a new method for counting breeding Purple Herons Ardea purpurea on a large wetland complex (Po Delta, Italy) using Google Earth satellite imagery in comparison to traditional ground counts in 2017. Google Earth counts provide an accurate, rapid, and inexpensive method for estimating the breeding population of Purple Herons, both saving time and increasing count accuracy in comparison to ground counts.","PeriodicalId":55353,"journal":{"name":"Bird Study","volume":"68 1","pages":"426 - 430"},"PeriodicalIF":0.7,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42604822","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 : 2021-07-03DOI: 10.1080/00063657.2022.2049204
U. Bergmanis, A. Auniņš
ABSTRACT Capsule Small rodents and amphibians are both important prey items for the Lesser Spotted Eagle Clanga pomarina, and their proportions in the diet depend on their local availability, as well as the degree of involvement of the female in food provisioning to the nestlings, which increases towards the end of the breeding season. Aims To describe the diet composition and aspects of the food supply of the Lesser Spotted Eagle during the nesting period. Methods Cameras were installed at five nests of three pairs of the Lesser Spotted Eagle in eastern Latvia, to collect data on food items brought to the nests. Results Of 3109 identified prey items, small rodents (43.36%) and amphibians (44.81%) were the most important prey groups. The proportion of common (small rodents and amphibians) and uncommon (moles, birds and others) food items differed between nests and years. Among the common food items, the deficiency of small rodents in some years was compensated for by an increase in frogs and vice versa. Male eagles brought 66% of all food items to the nest. Females brought more amphibians and fewer rodents than did males. After hatching, the mean number of food items delivered to the nest was 6.9 per day. The main activity period of food delivery was between the 3rd to 7th hour after sunrise. Conclusion The alternative prey hypothesis explains the diet of the Lesser Spotted Eagle in our study area. Rodents and amphibians are food items of equal importance that can replace each other, depending on their availability. The increasing share of amphibians towards the end of the breeding season was mainly a result of an increasing proportion of prey items brought into the nest by females.
{"title":"Diet composition and food supply of the Lesser Spotted Eagle Clanga pomarina in the core area of its breeding range","authors":"U. Bergmanis, A. Auniņš","doi":"10.1080/00063657.2022.2049204","DOIUrl":"https://doi.org/10.1080/00063657.2022.2049204","url":null,"abstract":"ABSTRACT Capsule Small rodents and amphibians are both important prey items for the Lesser Spotted Eagle Clanga pomarina, and their proportions in the diet depend on their local availability, as well as the degree of involvement of the female in food provisioning to the nestlings, which increases towards the end of the breeding season. Aims To describe the diet composition and aspects of the food supply of the Lesser Spotted Eagle during the nesting period. Methods Cameras were installed at five nests of three pairs of the Lesser Spotted Eagle in eastern Latvia, to collect data on food items brought to the nests. Results Of 3109 identified prey items, small rodents (43.36%) and amphibians (44.81%) were the most important prey groups. The proportion of common (small rodents and amphibians) and uncommon (moles, birds and others) food items differed between nests and years. Among the common food items, the deficiency of small rodents in some years was compensated for by an increase in frogs and vice versa. Male eagles brought 66% of all food items to the nest. Females brought more amphibians and fewer rodents than did males. After hatching, the mean number of food items delivered to the nest was 6.9 per day. The main activity period of food delivery was between the 3rd to 7th hour after sunrise. Conclusion The alternative prey hypothesis explains the diet of the Lesser Spotted Eagle in our study area. Rodents and amphibians are food items of equal importance that can replace each other, depending on their availability. The increasing share of amphibians towards the end of the breeding season was mainly a result of an increasing proportion of prey items brought into the nest by females.","PeriodicalId":55353,"journal":{"name":"Bird Study","volume":"68 1","pages":"319 - 329"},"PeriodicalIF":0.7,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42477889","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 : 2021-07-03DOI: 10.1080/00063657.2022.2026876
Tina Petras, A. Vrezec
ABSTRACT Capsule Long-term and non-standardized migratory bird ringing data can be used in models controlling variation in bird ringing methodology for reliable population trend estimations. Aims Bird ringing data usually cover long periods and might reflect long-term population changes. However, they are mainly derived during non-standardized multi-species catching at numerous sites during the autumn migration period. We searched for the best modelling approach to determine reliable species population dynamics and trend estimation models based on annual multi-species bird ringing data. Methods We used ringing data from the Slovenian Bird Ringing Scheme and selected data in three steps according to temporal, quantitative, and qualitative data selection. Annual indices were constructed based on two types of denominators, ringing days, and ringing totals, vs. a robust model without a denominator. We ran 20 candidate-generalized additive models describing migrating population dynamics for 15 bird species by combining different data selection approaches and denominators. Results We found that the models were species-specific, although the universal model could also be applied to most species. We propose a general model construction approach for population trend assessments from non-standardized bird ringing data. The estimates obtained by this approach were comparable to the overall European population trends derived from breeding survey data. Conclusions Bird ringing data from the autumn migration period are a valuable resource for assessing continental scale population trends taking into account the whole population (non-breeders and juveniles included) and even some rare and endangered species, but should be conducted according to standard protocols to ensure reliable statistical inference of population trends.
{"title":"Modelling population dynamics and trends in migratory birds from non-standardized multi-species ringing data: the potential of multi-model selection","authors":"Tina Petras, A. Vrezec","doi":"10.1080/00063657.2022.2026876","DOIUrl":"https://doi.org/10.1080/00063657.2022.2026876","url":null,"abstract":"ABSTRACT Capsule Long-term and non-standardized migratory bird ringing data can be used in models controlling variation in bird ringing methodology for reliable population trend estimations. Aims Bird ringing data usually cover long periods and might reflect long-term population changes. However, they are mainly derived during non-standardized multi-species catching at numerous sites during the autumn migration period. We searched for the best modelling approach to determine reliable species population dynamics and trend estimation models based on annual multi-species bird ringing data. Methods We used ringing data from the Slovenian Bird Ringing Scheme and selected data in three steps according to temporal, quantitative, and qualitative data selection. Annual indices were constructed based on two types of denominators, ringing days, and ringing totals, vs. a robust model without a denominator. We ran 20 candidate-generalized additive models describing migrating population dynamics for 15 bird species by combining different data selection approaches and denominators. Results We found that the models were species-specific, although the universal model could also be applied to most species. We propose a general model construction approach for population trend assessments from non-standardized bird ringing data. The estimates obtained by this approach were comparable to the overall European population trends derived from breeding survey data. Conclusions Bird ringing data from the autumn migration period are a valuable resource for assessing continental scale population trends taking into account the whole population (non-breeders and juveniles included) and even some rare and endangered species, but should be conducted according to standard protocols to ensure reliable statistical inference of population trends.","PeriodicalId":55353,"journal":{"name":"Bird Study","volume":"68 1","pages":"330 - 344"},"PeriodicalIF":0.7,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42419911","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 : 2021-07-03DOI: 10.1080/00063657.2022.2092593
R. Ziani, A. Lazli, F. Marniche, B. E. Ziani, B. Dik
ABSTRACT Capsule The distribution and prevalence of chewing lice found on Common Moorhens Gallinula chloropus varied between seasons and peaked during the winter. There was also significant variation in how lice were distributed around the body regions of the hosts. Aims To identify the species of lice found on the Common Moorhen, evaluate the seasonal variation in their intensity of infestation and determine spatial distribution on the hosts. Methods Eighty-six Common Moorhens were captured, examined for lice, and released from December 2018 to February 2020 at Lake Tonga, Algeria. Lice were extracted, preserved in 70% ethanol, cleared, and mounted in Canada balsam for identification. The population mean intensity and prevalence of lice species were calculated for each season. Data were inspected using descriptive statistical tools, such as principal component analysis, to explore spatial dispersion on the body regions of the hosts. Results Five louse species were identified: Pseudomenopon pilosum, Rallicola minutus, Laemobothrion chloropodis, Fulicoffula sp, and Incidifrons gallinulae, with percentages of prevalence of 79.07%, 70.93%, 56.98%, 40.70%, and 23.26%, respectively. Their prevalence varied significantly across months, with a peak in the winter. Louse species were non-randomly distributed across the body regions of the hosts. Conclusion This study documents the distribution and diversity of chewing lice on the Common Moorhen for the first time in Algeria and establishes a baseline dataset for further monitoring studies.
{"title":"The distribution and diversity of chewing lice (Phthiraptera) on the Common Moorhen Gallinula chloropus in Algeria","authors":"R. Ziani, A. Lazli, F. Marniche, B. E. Ziani, B. Dik","doi":"10.1080/00063657.2022.2092593","DOIUrl":"https://doi.org/10.1080/00063657.2022.2092593","url":null,"abstract":"ABSTRACT Capsule The distribution and prevalence of chewing lice found on Common Moorhens Gallinula chloropus varied between seasons and peaked during the winter. There was also significant variation in how lice were distributed around the body regions of the hosts. Aims To identify the species of lice found on the Common Moorhen, evaluate the seasonal variation in their intensity of infestation and determine spatial distribution on the hosts. Methods Eighty-six Common Moorhens were captured, examined for lice, and released from December 2018 to February 2020 at Lake Tonga, Algeria. Lice were extracted, preserved in 70% ethanol, cleared, and mounted in Canada balsam for identification. The population mean intensity and prevalence of lice species were calculated for each season. Data were inspected using descriptive statistical tools, such as principal component analysis, to explore spatial dispersion on the body regions of the hosts. Results Five louse species were identified: Pseudomenopon pilosum, Rallicola minutus, Laemobothrion chloropodis, Fulicoffula sp, and Incidifrons gallinulae, with percentages of prevalence of 79.07%, 70.93%, 56.98%, 40.70%, and 23.26%, respectively. Their prevalence varied significantly across months, with a peak in the winter. Louse species were non-randomly distributed across the body regions of the hosts. Conclusion This study documents the distribution and diversity of chewing lice on the Common Moorhen for the first time in Algeria and establishes a baseline dataset for further monitoring studies.","PeriodicalId":55353,"journal":{"name":"Bird Study","volume":"68 1","pages":"359 - 369"},"PeriodicalIF":0.7,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49083625","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 : 2021-07-03DOI: 10.1080/00063657.2022.2032590
Michał Budka, Patryk Kokociński
ABSTRACT Capsule The vocal activity of Common Cranes Grus grus varies with time of day, season, population abundance, and nesting habitat area, and consequently affects the accuracy and precision of single survey estimates of breeding population size. Aims To examine (1) how the vocal activity of Common Cranes varies during the day and seasonally, (2) how these changes affect the probability of observer detection of a pair during a single survey, and (3) which environmental variables influence vocal activity. Methods Autonomous sound recorders recorded soundscapes (24 hours per day) in 24 occupied territories of Common Cranes, three times during the breeding season. Recordings were analysed by manual spectrogram scanning. The probability of detection was calculated for four survey durations: 10 and 30 min, one and two hours. Environmental characteristics were measured from satellite images. Results Common Crane vocal activity during a single survey significantly varied during the day, decreased with the progress of the breeding season, negatively correlated with the area of nesting habitat, and positively correlated with the number of neighbouring pairs within 2 km. 24-hour surveys recorded at least one vocalization in 96% of occupied territories in March, 67% in April, and 46% in May. The highest probability of detection during a single, one-hour survey ranged from 0.46 in March, 0.25 in April to 0.17 in May. Reducing survey duration from 1 h to 10 min caused a decrease of detection to 0.29 in March and 0.13 in April and May. Conclusions We recommend surveying Common Cranes at the beginning of the breeding season, from one hour before sunrise to four hours after sunrise and from sunset to one hour after sunset, to ensure the highest (0.33–0.46) probability of detection during a single, one-hour survey. Alternatively, autonomous sound recorders may ensure detection of almost 100% of breeding pairs during a single, 24-hour survey at the beginning of the breeding season.
{"title":"Daily and seasonal changes of vocal activity of the Common Crane Grus grus: implications for conservation and monitoring efforts","authors":"Michał Budka, Patryk Kokociński","doi":"10.1080/00063657.2022.2032590","DOIUrl":"https://doi.org/10.1080/00063657.2022.2032590","url":null,"abstract":"ABSTRACT Capsule The vocal activity of Common Cranes Grus grus varies with time of day, season, population abundance, and nesting habitat area, and consequently affects the accuracy and precision of single survey estimates of breeding population size. Aims To examine (1) how the vocal activity of Common Cranes varies during the day and seasonally, (2) how these changes affect the probability of observer detection of a pair during a single survey, and (3) which environmental variables influence vocal activity. Methods Autonomous sound recorders recorded soundscapes (24 hours per day) in 24 occupied territories of Common Cranes, three times during the breeding season. Recordings were analysed by manual spectrogram scanning. The probability of detection was calculated for four survey durations: 10 and 30 min, one and two hours. Environmental characteristics were measured from satellite images. Results Common Crane vocal activity during a single survey significantly varied during the day, decreased with the progress of the breeding season, negatively correlated with the area of nesting habitat, and positively correlated with the number of neighbouring pairs within 2 km. 24-hour surveys recorded at least one vocalization in 96% of occupied territories in March, 67% in April, and 46% in May. The highest probability of detection during a single, one-hour survey ranged from 0.46 in March, 0.25 in April to 0.17 in May. Reducing survey duration from 1 h to 10 min caused a decrease of detection to 0.29 in March and 0.13 in April and May. Conclusions We recommend surveying Common Cranes at the beginning of the breeding season, from one hour before sunrise to four hours after sunrise and from sunset to one hour after sunset, to ensure the highest (0.33–0.46) probability of detection during a single, one-hour survey. Alternatively, autonomous sound recorders may ensure detection of almost 100% of breeding pairs during a single, 24-hour survey at the beginning of the breeding season.","PeriodicalId":55353,"journal":{"name":"Bird Study","volume":"68 1","pages":"311 - 318"},"PeriodicalIF":0.7,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48133043","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}
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