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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ftunivtasecite:oai:ecite.utas.edu.au:150550 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://doi.org/10.6084/m9.figshare.19709476 http://ecite.utas.edu.au/150550 en eng Ornithological Society of New Zealand Inc. http://ecite.utas.edu.au/150550/1/150550 - Erect-crested penguins on the Bounty Islands.pdf http://dx.doi.org/10.6084/m9.figshare.19709476 Mattern, T and Rexer-Huber, K and Parker, G and Amey, J and Green, CP and Tennyson, AJD and Sagar, PM and Thompson, DR, Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys, Notornis, 68 pp. 37-50. ISSN 0029-4470 (2021) [Refereed Article] http://ecite.utas.edu.au/150550 Biological Sciences Ecology Population ecology Refereed Article PeerReviewed 2021 ftunivtasecite https://doi.org/10.6084/m9.figshare.19709476 2022-08-22T22:17:06Z 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 eCite UTAS (University of Tasmania) 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 |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Biological Sciences Ecology Population ecology |
spellingShingle |
Biological Sciences Ecology Population ecology 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 |
Biological Sciences Ecology Population ecology |
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://doi.org/10.6084/m9.figshare.19709476 http://ecite.utas.edu.au/150550 |
long_lat |
ENVELOPE(-108.218,-108.218,56.050,56.050) ENVELOPE(53.683,53.683,-65.850,-65.850) |
geographic |
Four Islands Proclamation Island |
geographic_facet |
Four Islands Proclamation Island |
genre |
Bounty Islands Proclamation Island |
genre_facet |
Bounty Islands Proclamation Island |
op_relation |
http://ecite.utas.edu.au/150550/1/150550 - Erect-crested penguins on the Bounty Islands.pdf http://dx.doi.org/10.6084/m9.figshare.19709476 Mattern, T and Rexer-Huber, K and Parker, G and Amey, J and Green, CP and Tennyson, AJD and Sagar, PM and Thompson, DR, Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys, Notornis, 68 pp. 37-50. ISSN 0029-4470 (2021) [Refereed Article] http://ecite.utas.edu.au/150550 |
op_doi |
https://doi.org/10.6084/m9.figshare.19709476 |
_version_ |
1766380546721579008 |