Thursday, November 5, 2015

"634 wildebeest.... and 1 zebra."

Part of our job as researchers is to paint a complete picture of the world our hyenas live in. Understanding how their environment affects their day-to-day lives is a huge part of this project, so we strive to give our usual behavioral and physiological data collection a little context. To this end we record daily temperatures and rainfall as well as every RA’s favorite biweekly chore: prey censuses!  
It's very kind of these topi to walk in a nice slow line for us. 
Twice a month between the hours of 7:00am and 9:00am, we put our counting hats on and drive a series of pre-set tracks (known as “transects” in researcher lingo) to record the number of prey animals along these tracks. Using a laser rangefinder, we count every large mammal (with ostriches as an added bonus) within 100m of the road.

Baby zebras: notorious for hiding under Mom. Darn all those stripes!
Some days, this is as easy as counting a grand total of one warthog trotting along in the tall grass. Other days, such as when the great wildebeest migration rolls into town, counting every animal gets a whole lot harder. During a recent census, we counted 2,273 wildebeest along one brief stretch of road.
A sight that's sure to make any RA go "uh-oh." You know, wildebeest, this makes the whole "driver counts the right side of the road, passenger counts the left side" system a lot harder. 
As frustrating as it can be to count 80 zebra in one spot who all refuse to stand still, these data can be used to shed a little light on the world of the hyena. For example, a past paper used prey censuses to understand how hyenas change their preferred hunting targets based on relative abundance (Holekamp 1997). So as long as our data collection is useful to the project, we’re happy to count as many antelope as are thrown at us! (But please don’t throw antelopes at us.)

Work Cited:

Holekamp, K. E., Smale, L., Berg, R. and Cooper, S. M. (1997), Hunting rates and hunting success in the spotted hyena (Crocuta crocuta). Journal of Zoology, 242: 1–15. doi: 10.1111/j.1469-7998.1997.tb02925.x

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