Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys
In October 2019, an expedition to the subantarctic Bounty Islands provided the opportunity to conduct comprehensive ground counts of erect-crested penguins to assess population size and compare numbers to previous surveys. The entirety of Proclamation Island, an erect-crested penguins' strongho...
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Ornithological Society of New Zealand Inc.
2021
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ftunivtasmania:oai:eprints.utas.edu.au:46914 2023-05-15T15:45:54+02:00 Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys Mattern, T Rexer-Huber, K Parker, G Amey, J Green, CP Tennyson, AJD Sagar, PM Thompson, DR 2021 application/pdf https://eprints.utas.edu.au/46914/ https://eprints.utas.edu.au/46914/1/150550%20-%20Erect-crested%20penguins%20on%20the%20Bounty%20Islands.pdf en eng Ornithological Society of New Zealand Inc. https://eprints.utas.edu.au/46914/1/150550%20-%20Erect-crested%20penguins%20on%20the%20Bounty%20Islands.pdf Mattern, T, Rexer-Huber, K, Parker, G, Amey, J, Green, CP, Tennyson, AJD, Sagar, PM and Thompson, DR 2021 , 'Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys' , Notornis, vol. 68 , pp. 37-50 , doi:10.6084/m9.figshare.19709476 <http://dx.doi.org/10.6084/m9.figshare.19709476>. erect-crested penguin nest counts drone survey nest densities population trends New Zealand fur seal subantarctic islands Bounty Islands Article PeerReviewed 2021 ftunivtasmania https://doi.org/10.6084/m9.figshare.19709476 2022-08-22T22:16:41Z In October 2019, an expedition to the subantarctic Bounty Islands provided the opportunity to conduct comprehensive ground counts of erect-crested penguins to assess population size and compare numbers to previous surveys. The entirety of Proclamation Island, an erect-crested penguins' stronghold, was surveyed and number of active penguin nests was determined via ground counts. Drone surveys aiming at assessing seal numbers, provided high-resolution aerial photography allowing spatial analysis of penguin nest densities on four islands, i.e. Proclamation, Tunnel, Spider, and Ranfurly Islands. A total of 2,867 penguin nests were counted on Proclamation Island between 24 and 29 October. Adjusting for the earlier timing of the survey compared to counts conducted since 1997, nest numbers were only marginally lower (~2.4%) than in 1997 and 2004 suggesting that the penguin population has remained stable for the past 20 years; a ~10% reduction in penguin numbers in 2011 seems to be related to warmer than average ocean temperatures that year. Density analysis from drone imagery showed highly heterogenous distribution of penguin nests, with birds preferring areas sheltered from prevailing south-westerly winds. This also means that a previous estimate from 1978 which relied on uniform extrapolation of nest densities to what was assumed to suitable breeding areas substantially overestimated the true population size, thereby contributing to the species current 'endangered' threat ranking. Article in Journal/Newspaper Bounty Islands Proclamation Island University of Tasmania: UTas ePrints New Zealand Four Islands ENVELOPE(-108.218,-108.218,56.050,56.050) Proclamation Island ENVELOPE(53.683,53.683,-65.850,-65.850) |
institution |
Open Polar |
collection |
University of Tasmania: UTas ePrints |
op_collection_id |
ftunivtasmania |
language |
English |
topic |
erect-crested penguin nest counts drone survey nest densities population trends New Zealand fur seal subantarctic islands Bounty Islands |
spellingShingle |
erect-crested penguin nest counts drone survey nest densities population trends New Zealand fur seal subantarctic islands Bounty Islands Mattern, T Rexer-Huber, K Parker, G Amey, J Green, CP Tennyson, AJD Sagar, PM Thompson, DR Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys |
topic_facet |
erect-crested penguin nest counts drone survey nest densities population trends New Zealand fur seal subantarctic islands Bounty Islands |
description |
In October 2019, an expedition to the subantarctic Bounty Islands provided the opportunity to conduct comprehensive ground counts of erect-crested penguins to assess population size and compare numbers to previous surveys. The entirety of Proclamation Island, an erect-crested penguins' stronghold, was surveyed and number of active penguin nests was determined via ground counts. Drone surveys aiming at assessing seal numbers, provided high-resolution aerial photography allowing spatial analysis of penguin nest densities on four islands, i.e. Proclamation, Tunnel, Spider, and Ranfurly Islands. A total of 2,867 penguin nests were counted on Proclamation Island between 24 and 29 October. Adjusting for the earlier timing of the survey compared to counts conducted since 1997, nest numbers were only marginally lower (~2.4%) than in 1997 and 2004 suggesting that the penguin population has remained stable for the past 20 years; a ~10% reduction in penguin numbers in 2011 seems to be related to warmer than average ocean temperatures that year. Density analysis from drone imagery showed highly heterogenous distribution of penguin nests, with birds preferring areas sheltered from prevailing south-westerly winds. This also means that a previous estimate from 1978 which relied on uniform extrapolation of nest densities to what was assumed to suitable breeding areas substantially overestimated the true population size, thereby contributing to the species current 'endangered' threat ranking. |
format |
Article in Journal/Newspaper |
author |
Mattern, T Rexer-Huber, K Parker, G Amey, J Green, CP Tennyson, AJD Sagar, PM Thompson, DR |
author_facet |
Mattern, T Rexer-Huber, K Parker, G Amey, J Green, CP Tennyson, AJD Sagar, PM Thompson, DR |
author_sort |
Mattern, T |
title |
Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys |
title_short |
Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys |
title_full |
Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys |
title_fullStr |
Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys |
title_full_unstemmed |
Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys |
title_sort |
erect-crested penguins on the bounty islands: population size and trends determined from ground counts and drone surveys |
publisher |
Ornithological Society of New Zealand Inc. |
publishDate |
2021 |
url |
https://eprints.utas.edu.au/46914/ https://eprints.utas.edu.au/46914/1/150550%20-%20Erect-crested%20penguins%20on%20the%20Bounty%20Islands.pdf |
long_lat |
ENVELOPE(-108.218,-108.218,56.050,56.050) ENVELOPE(53.683,53.683,-65.850,-65.850) |
geographic |
New Zealand Four Islands Proclamation Island |
geographic_facet |
New Zealand Four Islands Proclamation Island |
genre |
Bounty Islands Proclamation Island |
genre_facet |
Bounty Islands Proclamation Island |
op_relation |
https://eprints.utas.edu.au/46914/1/150550%20-%20Erect-crested%20penguins%20on%20the%20Bounty%20Islands.pdf Mattern, T, Rexer-Huber, K, Parker, G, Amey, J, Green, CP, Tennyson, AJD, Sagar, PM and Thompson, DR 2021 , 'Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys' , Notornis, vol. 68 , pp. 37-50 , doi:10.6084/m9.figshare.19709476 <http://dx.doi.org/10.6084/m9.figshare.19709476>. |
op_doi |
https://doi.org/10.6084/m9.figshare.19709476 |
_version_ |
1766380546013790208 |