Ecological Archives M084-012-A5

J. Grant C. Hopcraft, J. M. Morales, H. L. Beyer, Markus Borner, Ephraim Mwangomo, A. R. E. Sinclair, Han Olff, Daniel T. Haydon. 2014. Competition, predation, and migration: individual choice patterns of Serengeti migrants captured by hierarchical models. Ecological Monographs 84:355–372. http://dx.doi.org/10.1890/13-1446.1

Appendix E. Frequency histogram of the average wildebeest herd size estimated from systematic ground transects.

Ground transects are repeatedly driven in Serengeti and the number of wildebeest are counted at points located every kilometer (n = 1065). Only the wildebeest within a semi-circle of 100-m radius in front of the vehicle are counted. Results from the transects show that wildebeest have never been recorded alone, and that they are most likely to be found in groups of 10 to 50 animals (about 40% of the time). Approximately 74% of the observations had between 50 and 200 animals, while less than 10% of the observations had 5 animals or fewer. Because wildebeest generally occur in large groups, they gain the advantage of group vigilance and the chances of an individual being killed by a predator are diluted.

FigE1

Fig. E1. Frequency histogram of the number of wildebeest counted per point along 1065 kilometers of transect. Data excludes all points in which no wildebeest were counted (i.e., only non-zero values).


[Back to M084-012]