Using measurements to predict laying order in harvested Northern Rockhopper Penguin (Eudyptes moseleyi) eggs
Alexander L. Bond A D , Gregory T. W. McClelland A B , Peter G. Ryan C and Trevor Glass B
+ Author Affiliations
- Author Affiliations
A RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire SG19 2DL, United Kingdom.
B Conservation Department, Government of Tristan da Cunha, Edinburgh of the Seven Seas, Tristan da Cunha TDCU 1ZZ, South Atlantic Ocean.
C Percy FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch 7001, South Africa.
D Corresponding author. Email: alex.bond@rspb.org.uk
Emu 116(4) 467-471 https://doi.org/10.1071/MU16027
Submitted: 23 March 2016 Accepted: 14 July 2016 Published: 15 August 2016
Abstract
The sustainable and responsible exploitation of natural populations for subsistence requires a scientific basis for management. Eggs of the Endangered Northern Rockhopper Penguin (Eudyptes moseleyi) in the Tristan da Cunha archipelago have been harvested since the 19th century with no restrictions on which (A- or B-eggs) can be harvested, despite the larger B-egg being much more likely to produce fledged offspring. Our objective was to create a discriminant function to predict the laying order of harvested eggs. We found that the discriminant function of D = 0.58 × Length + 0.39 × Breadth –57.48 successfully classified 91% of eggs as A- or B-eggs. When applied to previously collected harvest data, the discriminant function identified at least 36% of eggs as B-eggs. The method we describe here provides a mechanism around which one aspect of a management framework for the sustainable harvest of Northern Rockhopper Penguin eggs can be built.
Additional keywords: discriminant function, Spheniscidae, subsistence harvest, Tristan da Cunha, wildlife management.
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