Monday, November 12, 2012

Wildebeest Drownings

Part of what has kept us so busy over the last few weeks is that we've had two large wildebeest drowning events in the river. One of the major goals of our research is to document these events and determine how they affect the river. However, they're fairly uncommon and essentially impossible to predict, so when they happen, we drop whatever else we are doing and focus all our efforts on documenting them.

On Oct. 17, approximately 3,500 wildebeest drowned in a crossing at a very bad location in the river, just upstream of the Serena lunch spot. Although there is easy access into the river, there is almost no path out on the other side. There are a few narrow trails up a rocky bank, but these get slippery and inaccessible quickly, and with the high water levels we've been having, many animals wash downstream and miss the exit.

On Nov. 5, another drowning occurred at the same location, and approximately 3,000 animals drowned. We received a phone call in the morning and were able to make it to Purungat Bridge just in time to count the carcasses as they washed downstream under the bridge.

The rangers are actively trying to prevent the wildebeest from crossing at this location, but it's very difficult. The wildebeest have an incredible herd instinct, and once they have set their minds on crossing at a certain place, it's very difficult to dissuade them. However, the migration is mostly over now, so hopefully we won't experience any more major crossings at this particular site.

To help us get an estimate of how quickly a carcass breaks down in the river, we set up one of our game cameras on a pileup of about 350 carcasses that were lodged in the river. It was amazing to watch the role of vultures and maribou storks in breaking down the carcasses, but even more fascinating was what happened when a large storm came through on Nov. 27. Check out this time lapse video to see 4 days unfold in just 28 seconds...

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