Sexing Cape Vulture Gyps coprotheres based on head morphometrics |
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| Authors: | Margaret T Hirschauer Tapiwa Zimunya Ara Monadjem |
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| Institution: | 1. VulPro NPC, Skeerpoort, South Africa;2. DST/NRF Centre of Excellence at the FitzPatrick Institute of African Ornithology, Department of Biological Sciences, University of Cape Town, Cape Town, South Africa;3. All Out Africa Research Unit, Department of Biological Sciences, University of Swaziland, Kuwaluseni, Swaziland;4. Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa |
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| Abstract: | The Cape Vulture Gyps coprotheres is considered sexually monomorphic in the literature, but visual differences in head shape between the sexes have been observed. Furthermore, head morphometrics of other Gyps species show statistically significant variation between the sexes. We show that head morphometrics can be used to determine the sex of Cape Vultures. Males generally have wider and shorter heads, and larger bill depths than females. Discriminant function analysis with data from 63 individuals identified the three most predictive variables in sex determination to be head width, head length and bill depth. We also provide an equation that can be used in conjunction with head measurements as a method to determine the sex of Cape Vultures in the field with an overall accuracy of 84% (92% accuracy for females and 72% for males). |
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| Keywords: | Cape Vulture head morphometrics sexual dimorphism |
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