- Title
- Stable detection frequency of the threatened Christmas Island Boobook Ninox natalis, 2012–2022
- Creator
- Tiernan, Brendan; Woinarski, John C. Z.; Legge, Sarah M.; Southwell, Darren; Barry Baker, G.; Hill, F.; James, David J.; Macgregor, Nicholas A.; Flakus, Samantha; Garnett, Stephen T.
- Relation
- Emu - Austral Ornithology Vol. 125, Issue 1, p. 24-34
- Publisher Link
- http://dx.doi.org/10.1080/01584197.2024.2408541
- Publisher
- Taylor & Francis
- Resource Type
- journal article
- Date
- 2025
- Description
- Both island species and raptors are at particularly high risk of extinction but few island raptor populations have been the subject of long-term monitoring. To determine trends in abundance in the Christmas Island Boobook, surveys were conducted annually from 2012–2017, in 2019 and in 2022. Across the survey period the population appears to have been either stable or to have increased slightly. Almost no part of the island lacked owls during the most recent survey. The detection rate averaged 1.56 (out of four surveys at a site); it was lowest in 2013 (1.22) and highest in 2022 (2.38). Detection was more likely on nights with low wind, at wetter sites and in closed vegetation, rather than in open or very low vegetation. In a separate analysis on the same data, the top-ranked dynamic occupancy-detection model found that occupancy increased with increasing elevation and vegetation height. No effect of a suspected threat, the presence of invasive yellow crazy ants Anoplolepis gracilipes at a site, could be detected. We recommend ongoing monitoring and research, potentially using automated recording devices and the tracking of individual owls to understand and refine the assumptions underpinning the interpretation of survey results.
- Subject
- forest owl; island population; stability; habitat suitability modelling; monitoring; SDG 15; Sustainable Development Goal
- Identifier
- http://hdl.handle.net/1959.13/1518161
- Identifier
- uon:57242
- Identifier
- ISSN:0158-4197
- Rights
- © 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.
- Language
- eng
- Full Text
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