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RESEARCH ARTICLE
Contents Vol 34(1)

A morphological model for sexing nestling peregrine falcons (Falco peregrinus macropus) verified through genetic analysis

Victor G. Hurley A , Fiona Hogan A B , John G. White A and Raylene Cooke A C
+ Author Affiliations
- Author Affiliations

A School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Vic. 3125, Australia.

B Population and Evolutionary Genetics Unit, Museum Victoria, GPO Box 666E, Melbourne, Vic. 3001, Australia.

C Corresponding author. Email: raylene.cooke@deakin.edu.au

Wildlife Research 34(1) 54-58 https://doi.org/10.1071/WR06059
Submitted: 29 May 2006  Accepted: 5 January 2007   Published: 27 February 2007

Abstract

Adult peregrine falcons (Falco peregrinus macropus) have monotypic plumage and display strong reversed sexual dimorphism, with females significantly larger than males. Reversed sexual dimorphism is measurable among nestlings in the latter stages of their development and can therefore be used to differentiate between sexes. In the early stages of development, however, nestlings cannot be sexed with any degree of certainty because morphological differentiation between the sexes is not well developed. During this study we developed a model for sexing younger nestlings based on genetic analysis and morphometric data collected as part of a long-term banding study of this species. A discriminant function model based on morphological characteristics was developed for determining the sex of nestlings (n = 150) in the field and was shown to be 96.0% accurate. This predictive model was further tested against an independent morphometric dataset taken from a second group of nestlings (n = 131). The model correctly allocated sex to 96.2% of this second group of nestlings. Sex can reliably be determined (98.6% accurate) for nestlings that have a wing length of at least 9 cm using this model. Application of this model, therefore, allows the banding of younger nestlings and, as such, significantly increases the period of time over which banding can occur. Another important implication of this model is that by banding nestlings earlier, they are less likely to jump from the nest, therefore reducing the risk of injury to both the brood and the bander.


Acknowledgements

Thanks must first and foremost go to the volunteers of the Victorian Peregrine Project, in particular those that assisted in collecting morphometric data, namely: M. Manhal, P. Wignell, D. McKinty, J. Cashin, D. Hay, F. Cross, S. Moore and the various students especially M. Boulet, M. Awasthy, N. Wagner, B. Denis and S. Gelinet. Our heartfelt thanks go to Jim and Sherry Watson. We thank the following sponsors whose generous support made this project possible: Ford Motor Co. Australia, Boral Resources, the R. E. Ross Trust, Joyce W. Vickery Trust, Australian Geographic, Optus Communications, Readymix, Parks Victoria and Southern Cement and CMIL (owners of 367 Collins Street) and the postgraduate support program of Deakin University and the Holsworth Wildlife Research Endowment. Museum Victoria is thanked for providing validation samples and three anonymous referees for their comments on the paper. Birds Australia, in particular Chris Tzaros and Mike Weston, are thanked for providing assistance. This research was conducted under research permit number 10003190 and ABBBS Banding Authority No. 1705.


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