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Ground-based survey methods both overestimate and underestimate the abundance of suitable tree-cavities for the endangered Swift Parrot

Citation

Stojanociv, D and Webb, M and Roshier, D and Saunders, D and Heinsohn, R, Ground-based survey methods both overestimate and underestimate the abundance of suitable tree-cavities for the endangered Swift Parrot, Emu: Austral Ornithology, 112, (4) pp. 350-356. ISSN 0158-4197 (2012) [Refereed Article]

Copyright Statement

Copyright 2012 BirdLife Australia

DOI: doi:10.1071/MU11076

Abstract

Most cavity-dependent species select tree-cavities with a narrow range of characteristics so that only a small subset of available cavities may be suitable for any species. Most surveys for tree-cavities are done from the ground using binoculars to reduce effort, but this technique is prone to error. These errors are likely to contribute to the loss of the cavity resource when used to inform conservation efforts for cavity-dependent species. The Swift Parrot (Lathamus discolor) is an endangered migratory bird threatened by ongoing removal of cavity-bearing trees by production forestry. We climbed trees with cavities used for nesting by Swift Parrots and determined that they prefer cavities with small entrances, deep chambers and wide floors. Such cavities are rare and occur in large trees that support higher than average numbers of tree-cavities. Importantly, cavities used by Swift Parrots were also likely to be both overestimated and underestimated using ground-based surveys, and without calibration by climbing, the size and direction of survey error could not be determined. We conclude that the most effective way to gain detailed information about the characteristics and abundance of tree-cavities is to climb a representative sample of trees to calibrate ground-based methods for a specific ecosystem.

Item Details

Item Type:Refereed Article
Keywords:cavity availability, forestry, nest selection, survey error, tree hollow
Research Division:Environmental Sciences
Research Group:Environmental Science and Management
Research Field:Environmental Impact Assessment
Objective Division:Environment
Objective Group:Flora, Fauna and Biodiversity
Objective Field:Forest and Woodlands Flora, Fauna and Biodiversity
Author:Webb, M (Mr Matthew Webb)
ID Code:116394
Year Published:2012
Web of Science® Times Cited:17
Deposited By:Zoology
Deposited On:2017-05-09
Last Modified:2017-10-16
Downloads:0

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