Ecological Archives M084-012-A2
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 B. Methods regarding animal capture and handling, animal morphometrics, and details of GPS collars.
Female animals older than 2 and younger than 6 (based on tooth wear) were randomly selected from mixed herds dispersed over the plains of the Serengeti. Females face huge energetic demands during pregnancy and lactation (Hopcraft et al., in press) and are the most nutritionally constrained portion of the population. We selected females rather than males because males undergo less extreme annual energetic restrictions than females, and as a result the movement of males is less likely to be explainable by the variables we could measure such as food and predation.
All animals were immobilized by Tanzania National Parks or Tanzania Wildlife Research veterinarians using approximately 7 to 8 mg of Etorphine (M99) and reversed using Diprenorphine (M5050). The total time the animals were immobilized did not extend beyond 15 minutes, and all females were quickly re-united with the herds or harems. While immobilizing females with offspring, care was taken not to separate mothers for extended periods. Offspring would generally wait near by while their mothers were immobilized, and all females almost immediately found their calves (or foals) upon recovery. The average neck circumference for female wildebeest was 66 cm, and 68 cm for female zebra.
Lotek GPS1000 collars with VHF tracking and a UHF modem for remotely downloading data were used on wildebeest from 1999 to 2004. From 2005 to 2006 we deployed Televilt SatLink GPS collars with data transmission via satellite phone on both wildebeest and zebra. These collars were then replaced by Televilt Tellus Simplex GSM enabled GPS collars from 2006 to 2008, which proved to be the most reliable. GPS locations were collected at 00:00, 06:00, 12:00 and 18:00 daily from 1999 to 2004 and at 06:00 and 18:00 daily from 2005 onwards.
Hopcraft, J. G. C., R. M. Holdo, E. Mwangomo, S. A. R. Mduma, S. Thirgood, M. Borner, J. M. Fryxell, H. Olff, and A. R. E. Sinclair. In press. Why are wildebeest the most abundant herbivore in the Serengeti? In A. R. E. Sinclair, K. Metzger, S. A. R. Mduma, and J. M. Fryxell, editors. Serengeti IV. University of Chicago Press, Chicago, Illinois, USA.
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