Population fluctuations of gyrfalcon and rock ptarmigan: analysis of export figures from Iceland
We analysed harvest data for gyrfalcon Falco rusticolus and rock ptarmigan Lagopus mutus from Iceland with respect to regularity in fluctuations of numbers. The gyrfalcon data concerned live trapped birds exported to Denmark between 1731 and 1793, and totalled 4,848 falcons, including 4,318 grey, 15...
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crwiley:10.2981/wlb.1995.0011 2023-12-03T10:22:25+01:00 Population fluctuations of gyrfalcon and rock ptarmigan: analysis of export figures from Iceland Nielsen, Ólafur K. Pétursson, Gunnlaugur 1995 http://dx.doi.org/10.2981/wlb.1995.0011 https://onlinelibrary.wiley.com/doi/full-xml/10.2981/wlb.1995.0011 https://onlinelibrary.wiley.com/doi/pdf/10.2981/wlb.1995.0011 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Wildlife Biology volume 1, issue 2, page 65-71 ISSN 1903-220X 1903-220X Management, Monitoring, Policy and Law Nature and Landscape Conservation Ecology, Evolution, Behavior and Systematics journal-article 1995 crwiley https://doi.org/10.2981/wlb.1995.0011 2023-11-09T13:26:04Z We analysed harvest data for gyrfalcon Falco rusticolus and rock ptarmigan Lagopus mutus from Iceland with respect to regularity in fluctuations of numbers. The gyrfalcon data concerned live trapped birds exported to Denmark between 1731 and 1793, and totalled 4,848 falcons, including 4,318 grey, 156 half‐white and 374 white colour morphs. According to contemporary sources grey birds were part of the local breeding population ( islandus‐ type birds) but the other morphs represented mainly visitors from Greenland. This is also the current situation but some of the lightest Icelandic breeders could be classified as half‐white. The rock ptarmigan harvest data concerned birds exported to Europe in the period 1864–1919, in total ca 3.3 million birds. The data series for white and half‐white gyrfalcons were significantly correlated (r = 0.501, p < 0.001). The data series for grey and white morphs (r = ‐0.099, P = 0.445) and grey and the half‐white morphs (r = ‐0.1183, P = 0.360), showed no correlation. Time series analysis showed that the white ( candicans‐ type) morph fluctuated irregularly. The half‐white morph behaved similarly but also showed some affinity with the grey morph, and could have represented a mixture of local breeders and Greenlandic winter visitors. Grey morph gyrfalcons and rock ptarmigan showed regular fluctuations in numbers with a 10‐year periodicity. The reliance of Icelandic gyrfalcons on rock ptarmigan during the early part of the breeding season and in all phases of the ptarmigan cycle is well established and may offer a case for causal connections between the two cyclic populations. Article in Journal/Newspaper Falco rusticolus Greenland greenlandic gyrfalcon Iceland Lagopus mutus rock ptarmigan Wiley Online Library (via Crossref) Greenland Wildlife Biology 1 2 65 71 |
institution |
Open Polar |
collection |
Wiley Online Library (via Crossref) |
op_collection_id |
crwiley |
language |
English |
topic |
Management, Monitoring, Policy and Law Nature and Landscape Conservation Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Management, Monitoring, Policy and Law Nature and Landscape Conservation Ecology, Evolution, Behavior and Systematics Nielsen, Ólafur K. Pétursson, Gunnlaugur Population fluctuations of gyrfalcon and rock ptarmigan: analysis of export figures from Iceland |
topic_facet |
Management, Monitoring, Policy and Law Nature and Landscape Conservation Ecology, Evolution, Behavior and Systematics |
description |
We analysed harvest data for gyrfalcon Falco rusticolus and rock ptarmigan Lagopus mutus from Iceland with respect to regularity in fluctuations of numbers. The gyrfalcon data concerned live trapped birds exported to Denmark between 1731 and 1793, and totalled 4,848 falcons, including 4,318 grey, 156 half‐white and 374 white colour morphs. According to contemporary sources grey birds were part of the local breeding population ( islandus‐ type birds) but the other morphs represented mainly visitors from Greenland. This is also the current situation but some of the lightest Icelandic breeders could be classified as half‐white. The rock ptarmigan harvest data concerned birds exported to Europe in the period 1864–1919, in total ca 3.3 million birds. The data series for white and half‐white gyrfalcons were significantly correlated (r = 0.501, p < 0.001). The data series for grey and white morphs (r = ‐0.099, P = 0.445) and grey and the half‐white morphs (r = ‐0.1183, P = 0.360), showed no correlation. Time series analysis showed that the white ( candicans‐ type) morph fluctuated irregularly. The half‐white morph behaved similarly but also showed some affinity with the grey morph, and could have represented a mixture of local breeders and Greenlandic winter visitors. Grey morph gyrfalcons and rock ptarmigan showed regular fluctuations in numbers with a 10‐year periodicity. The reliance of Icelandic gyrfalcons on rock ptarmigan during the early part of the breeding season and in all phases of the ptarmigan cycle is well established and may offer a case for causal connections between the two cyclic populations. |
format |
Article in Journal/Newspaper |
author |
Nielsen, Ólafur K. Pétursson, Gunnlaugur |
author_facet |
Nielsen, Ólafur K. Pétursson, Gunnlaugur |
author_sort |
Nielsen, Ólafur K. |
title |
Population fluctuations of gyrfalcon and rock ptarmigan: analysis of export figures from Iceland |
title_short |
Population fluctuations of gyrfalcon and rock ptarmigan: analysis of export figures from Iceland |
title_full |
Population fluctuations of gyrfalcon and rock ptarmigan: analysis of export figures from Iceland |
title_fullStr |
Population fluctuations of gyrfalcon and rock ptarmigan: analysis of export figures from Iceland |
title_full_unstemmed |
Population fluctuations of gyrfalcon and rock ptarmigan: analysis of export figures from Iceland |
title_sort |
population fluctuations of gyrfalcon and rock ptarmigan: analysis of export figures from iceland |
publisher |
Wiley |
publishDate |
1995 |
url |
http://dx.doi.org/10.2981/wlb.1995.0011 https://onlinelibrary.wiley.com/doi/full-xml/10.2981/wlb.1995.0011 https://onlinelibrary.wiley.com/doi/pdf/10.2981/wlb.1995.0011 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Falco rusticolus Greenland greenlandic gyrfalcon Iceland Lagopus mutus rock ptarmigan |
genre_facet |
Falco rusticolus Greenland greenlandic gyrfalcon Iceland Lagopus mutus rock ptarmigan |
op_source |
Wildlife Biology volume 1, issue 2, page 65-71 ISSN 1903-220X 1903-220X |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.2981/wlb.1995.0011 |
container_title |
Wildlife Biology |
container_volume |
1 |
container_issue |
2 |
container_start_page |
65 |
op_container_end_page |
71 |
_version_ |
1784270352666329088 |