Bird Conservation International

Articles

The African wintering distribution and ecology of the Corncrake Crex crex

BRUNO A. WALTHERa1 c1, P. BARRY TAYLORa2, NORBERT SCHÄFFERa3, SUE ROBINSONa3 and FREDERIC JIGUETa4

a1 College of International Studies, National Pingtung University of Science and Technology (NPUST), Neipu, Taiwan, Republic of China; College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan, Republic of China.

a2 School of Biological & Conservation Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, Pietermaritzburg, South Africa.

a3 The Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire SG19 2DL, UK.

a4 Muséum National d’Histoire Naturelle, UMR 7204 MNHN-CNRS-UPMC, Centre de Recherches sur la Biologie sur des Populations d’Oiseaux (CRBPO), CP 51, 55 rue Buffon, 75005 Paris, France.

Summary

The Corncrake Crex crex breeds in the Palearctic but overwinters in central and southern Africa. While some information had previously been gathered about the Corncrake’s African wintering distribution, we here analyse a much more comprehensive database of 1,284 records based on a five-year desk study completed in January 2011 and use those records selected for spatio-temporal accuracy to build a continental distribution model. Our model was based mostly on climatic variables and predicts a high suitability for most eastern Africa countries south of the equator, but none of the western African countries with the exception of Angola and Namibia. Both the actual number of records as well as the distribution model thus indicates that the vast majority of Corncrakes migrate through and overwinter in the eastern parts of Africa. Because large parts of Angola, Mozambique, north-eastern Namibia, and Tanzania are predicted as suitable but have yielded very few actual records so far, they should be targeted for future field work. A very small number of Corncrakes may oversummer in Africa but such individuals are possibly unable to migrate due to sickness or injury, or may be first-year birds that are not ready to breed. An analysis of habitat and population density data indicates that, within the continental distribution, Corncrakes are mostly concentrated within grass-dominated habitats, mirroring their habitat preferences in the breeding areas. Corncrakes reach their wintering distribution mostly through an eastern migration route, but some individuals or subpopulations from the Western breeding population also use a western migration route. We also document the food choices, weights, and causes of injury and death within Africa. Because habitat conversion is accelerating all across Africa, we recommend constant monitoring of habitat availability and population densities within the Corncrake’s wintering distribution.

(Received June 23 2011)

(Accepted November 18 2011)

(Online publication July 06 2012)

Correspondence

c1 Author for correspondence; e-mail: bawalther2009@gmail.com