Age and sex ratios of wintering Long-tailed Ducks Clangula hyemalis can be determined by analysis of photos of flying flocks at sea: A method description
The West Siberian/North European population of Long-tailed Duck Clangula hyemalis that breeds in Fennoscandia and Northwestern Russia, and winters in the Baltic Sea, has declined by at least 65% since the 1990s and is classified as globally vulnerable. To propose effective management actions to stop...
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BirdLife Sweden
2023
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Online Access: | https://journals.lub.lu.se/os/article/view/23757 https://doi.org/10.34080/os.v33.23757 |
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ftunivlundojs:oai:journals.lub.lu.se:article/23757 2023-05-15T16:11:53+02:00 Age and sex ratios of wintering Long-tailed Ducks Clangula hyemalis can be determined by analysis of photos of flying flocks at sea: A method description Ålders- och könskvoter hos övervintrande alfåglar Clangula hyemalis kan bestämmas genom analys av foton av flygande flockar till havs: en metodbeskrivning Larsson, Kjell 2023-03-06 application/pdf https://journals.lub.lu.se/os/article/view/23757 https://doi.org/10.34080/os.v33.23757 eng eng BirdLife Sweden https://journals.lub.lu.se/os/article/view/23757/22131 https://journals.lub.lu.se/os/article/view/23757 doi:10.34080/os.v33.23757 Copyright (c) 2023 Kjell Larsson http://creativecommons.org/licenses/by/4.0 CC-BY Ornis Svecica; Vol. 33 (2023); 1–20 Ornis Svecica; Vol 33 (2023); 1–20 2003-2633 1102-6812 Baltic Sea population dynamics reproductive success flock structure plumage Östersjön populationsdynamik häckningsframgång flockstruktur fjäderdräkt info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Peer-reviewed Research Paper Fackgranskad uppsats 2023 ftunivlundojs https://doi.org/10.34080/os.v33.23757 2023-03-08T23:27:59Z The West Siberian/North European population of Long-tailed Duck Clangula hyemalis that breeds in Fennoscandia and Northwestern Russia, and winters in the Baltic Sea, has declined by at least 65% since the 1990s and is classified as globally vulnerable. To propose effective management actions to stop the decline, knowledge about demographic parameters is required. A photo survey method by which it is possible, in winter, to collect data on sex ratios and production of first-winter birds is presented here. The plumage traits and bill patterns, which are detectable in photos taken at a distance, are described. The traits can be used to discriminate between three categories of birds: adult males, first-winter males, and females. To extrapolate results from several photo surveys and obtain population-wide estimates of demographic parameters, knowledge about non-random distributions of different bird categories is needed. It was found that different age and sex categories were distributed differently across flocks of different sizes. The required sample sizes and the possible constraints and biases related to the photo survey method are discussed. The West Siberian/North European population of Long-tailed Duck Clangula hyemalis that breeds in Fennoscandia and Northwestern Russia, and winters in the Baltic Sea, has declined by at least 65% since the 1990s and is classified as globally vulnerable. To propose effective management actions to stop the decline, knowledge about demographic parameters is required. A photo survey method by which it is possible, in winter, to collect data on sex ratios and production of first-winter birds is presented here. The plumage traits and bill patterns, which are detectable in photos taken at a distance, are described. The traits can be used to discriminate between three categories of birds: adult males, first-winter males, and females. To extrapolate results from several photo surveys and obtain population-wide estimates of demographic parameters, knowledge about non-random ... Article in Journal/Newspaper Fennoscandia Open Journals at Lund University (OJLU) Ornis Svecica 33 1 20 |
institution |
Open Polar |
collection |
Open Journals at Lund University (OJLU) |
op_collection_id |
ftunivlundojs |
language |
English |
topic |
Baltic Sea population dynamics reproductive success flock structure plumage Östersjön populationsdynamik häckningsframgång flockstruktur fjäderdräkt |
spellingShingle |
Baltic Sea population dynamics reproductive success flock structure plumage Östersjön populationsdynamik häckningsframgång flockstruktur fjäderdräkt Larsson, Kjell Age and sex ratios of wintering Long-tailed Ducks Clangula hyemalis can be determined by analysis of photos of flying flocks at sea: A method description |
topic_facet |
Baltic Sea population dynamics reproductive success flock structure plumage Östersjön populationsdynamik häckningsframgång flockstruktur fjäderdräkt |
description |
The West Siberian/North European population of Long-tailed Duck Clangula hyemalis that breeds in Fennoscandia and Northwestern Russia, and winters in the Baltic Sea, has declined by at least 65% since the 1990s and is classified as globally vulnerable. To propose effective management actions to stop the decline, knowledge about demographic parameters is required. A photo survey method by which it is possible, in winter, to collect data on sex ratios and production of first-winter birds is presented here. The plumage traits and bill patterns, which are detectable in photos taken at a distance, are described. The traits can be used to discriminate between three categories of birds: adult males, first-winter males, and females. To extrapolate results from several photo surveys and obtain population-wide estimates of demographic parameters, knowledge about non-random distributions of different bird categories is needed. It was found that different age and sex categories were distributed differently across flocks of different sizes. The required sample sizes and the possible constraints and biases related to the photo survey method are discussed. The West Siberian/North European population of Long-tailed Duck Clangula hyemalis that breeds in Fennoscandia and Northwestern Russia, and winters in the Baltic Sea, has declined by at least 65% since the 1990s and is classified as globally vulnerable. To propose effective management actions to stop the decline, knowledge about demographic parameters is required. A photo survey method by which it is possible, in winter, to collect data on sex ratios and production of first-winter birds is presented here. The plumage traits and bill patterns, which are detectable in photos taken at a distance, are described. The traits can be used to discriminate between three categories of birds: adult males, first-winter males, and females. To extrapolate results from several photo surveys and obtain population-wide estimates of demographic parameters, knowledge about non-random ... |
format |
Article in Journal/Newspaper |
author |
Larsson, Kjell |
author_facet |
Larsson, Kjell |
author_sort |
Larsson, Kjell |
title |
Age and sex ratios of wintering Long-tailed Ducks Clangula hyemalis can be determined by analysis of photos of flying flocks at sea: A method description |
title_short |
Age and sex ratios of wintering Long-tailed Ducks Clangula hyemalis can be determined by analysis of photos of flying flocks at sea: A method description |
title_full |
Age and sex ratios of wintering Long-tailed Ducks Clangula hyemalis can be determined by analysis of photos of flying flocks at sea: A method description |
title_fullStr |
Age and sex ratios of wintering Long-tailed Ducks Clangula hyemalis can be determined by analysis of photos of flying flocks at sea: A method description |
title_full_unstemmed |
Age and sex ratios of wintering Long-tailed Ducks Clangula hyemalis can be determined by analysis of photos of flying flocks at sea: A method description |
title_sort |
age and sex ratios of wintering long-tailed ducks clangula hyemalis can be determined by analysis of photos of flying flocks at sea: a method description |
publisher |
BirdLife Sweden |
publishDate |
2023 |
url |
https://journals.lub.lu.se/os/article/view/23757 https://doi.org/10.34080/os.v33.23757 |
genre |
Fennoscandia |
genre_facet |
Fennoscandia |
op_source |
Ornis Svecica; Vol. 33 (2023); 1–20 Ornis Svecica; Vol 33 (2023); 1–20 2003-2633 1102-6812 |
op_relation |
https://journals.lub.lu.se/os/article/view/23757/22131 https://journals.lub.lu.se/os/article/view/23757 doi:10.34080/os.v33.23757 |
op_rights |
Copyright (c) 2023 Kjell Larsson http://creativecommons.org/licenses/by/4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.34080/os.v33.23757 |
container_title |
Ornis Svecica |
container_volume |
33 |
container_start_page |
1 |
op_container_end_page |
20 |
_version_ |
1765997081004081152 |