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Population growth rates in northern Cape Vulture Gyps coprotheres colonies between 2010 and 2019

Published online by Cambridge University Press:  25 September 2020

MARGARET T. HIRSCHAUER*
Affiliation:
VulPro NPO, P.O. Box 285 Skeerpoort, South Africa0232.
KERRI WOLTER
Affiliation:
VulPro NPO, P.O. Box 285 Skeerpoort, South Africa0232.
ALEXANDRA HOWARD
Affiliation:
VulPro NPO, P.O. Box 285 Skeerpoort, South Africa0232.
BRIAN W. ROLEK
Affiliation:
The Peregrine Fund, 5668 W. Flying Hawk Lane, Boise, IDUSA83709.
CHRISTOPHER J. W. MCCLURE
Affiliation:
The Peregrine Fund, 5668 W. Flying Hawk Lane, Boise, IDUSA83709. School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, 2001, South Africa.
*
*Author for correspondence; email: mhirscha@gmail.com

Summary

The ‘Endangered’ Cape Vulture Gyps coprotheres has been monitored across its range for decades through disparate studies varying in geographical scope and length. Yet, no long-term, range-wide survey exists for the species. Coordinated monitoring across the range of the Cape Vulture would be logistically challenging but provide a holistic view of population dynamics in this long-lived species that forages across much of southern Africa. Here, we report breeding pair counts from seven colonies in the Cape Vulture’s north-eastern breeding region from 2010 to 2019. We used state-space models to assess population growth across time. Manutsa, Soutpansberg, and Nooitgedacht colonies increased significantly over the study period, with three other colonies having positive estimates of population growth, but 95% credible intervals overlapped zero. The smallest colony at Moletjie is declining toward extirpation; only one breeding pair remained in 2019. Our results suggest the north-eastern population has been stable or increasing since 2010 with our 2019 surveys counting 2,241 breeding pairs across all sites. Indeed, there is an 89% chance that the population across the colonies we monitored increased from 2010 to 2019. Coordinated, range-wide, full-cycle monitoring is needed to thoroughly assess conservation status and efficacy of conservation actions taken for this endangered species.

Type
Research Article
Copyright
© The Author(s) and VulPro, 2020. Published by Cambridge University Press on behalf of BirdLife International

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