Current address: Centre for Tropical Biodiversity & Climate Change, School of Marine and Tropical Biology, James Cook University, Townsville, Qld 4811, Australia.
Rainfall-related population growth and adult sex ratio change in the Critically Endangered Raso lark (Alauda razae)
Article first published online: 10 APR 2012
© 2012 The Authors. Animal Conservation © 2012 The Zoological Society of London
Volume 15, Issue 5, pages 466–471, October 2012
How to Cite
Brooke, M. d. L., Flower, T. P., Campbell, E. M., Mainwaring, M. C., Davies, S., Welbergen, J. A. (2012), Rainfall-related population growth and adult sex ratio change in the Critically Endangered Raso lark (Alauda razae). Animal Conservation, 15: 466–471. doi: 10.1111/j.1469-1795.2012.00535.x
- Issue published online: 2 OCT 2012
- Article first published online: 10 APR 2012
- Manuscript Accepted: 28 FEB 2012
- Manuscript Received: 27 SEP 2011
- Threatened bird;
- adult sex ratio;
- Cape Verdes;
- annual survival
Active conservation has often been successful in reversing or arresting population declines of endangered species. However, examples of Critically Endangered species recovering in the absence of human intervention are extremely rare. We censused the Raso lark, a single-island endemic of the Cape Verdes archipelago, annually from 2001 to 2010. Between 2004 and 2010, the world population grew from 65 to 470 individuals. This remarkable increase occurred without conservation intervention, but correlated strongly and positively with rainfall. Because of this population increase, the mean age of birds reduced and the population shifted from male skew, a consequence of higher male survival, towards one where the sexes were more equally represented. This study illustrates the dramatic effect that natural changes in climatic conditions may have on the recovery of endangered species. However, the current favourable situation may not persist, and we suggest a translocation to another Cape Verdean island be urgently considered. We conclude that temporal trends in the population dynamics of endangered populations need to be considered when planning and implementing species recovery plans.