Desert Forensics

A couple of days ago we found saw a number of Lappet Faced Vultures sitting about 1km from Sossusvlei Desert Lodge.  I didn't have time that day to go and have a look.  The next morning I went out early to have a look at what had been dead there.  It didn't take long to find the carcas...a dead adult male ostrich.

Trying to work out what happened was much harder.  Due to the great rain that the central Namib has had in recent years (2006, 2008 and 2009 especially) the grass is exceptionally thick.  At times these sandy planes have no grass at all.

Looking around a bit I could see that the bones had been dragged from where the bird had died.  On that spot there were numerous ostrich feathers.  In several of the barren fairy circles [see note] there were tracks where an ostrich had been sitting.  It was clear that it had not been running as it had sat several places near where it was killed and had never really run.  Clearly it hadn't been well before it's death.

I thought then that perhaps a small predator had killed it.  I couldn't find any clear predator tracks, but found a few that I thought could be.  I didn't find any tracks much larger than Jackals though, and thought that maybe it had been a very young cheetah.  I had thought that it had to be a predator because the whole thing was eaten so fast (within the day it had died it appeared.)  I could see it hadn't really run, but thought it was probably already very sick and had been virtually stalked right up to where it had been sitting.  Also there had been no thrashing around before it died, which with something like an Oryx often creates a hole in the ground around it's legs when it dies like that.

Later I was talking to Jeff, one of the other rangers working at Sossusvlei Desert Lodge.  He knows much more about pradators and their kills than I do.  So we went out together to have a look.  It didn't take long for him to exclude any large predator from making the kill.  There would have been many more good tracks of the predator.  At the place the bird had died there was no blood lying around.  Had it been killed, the blood on the ground would have been obvious.

So in the end we figured that it probably died from it's weakened condition.  It may be possible the Jackals may have made the final kill when the Ostrich had been dying anyway, but there was not involvement from  a large predator.  Basically this Ostrich was polished off by Jackals, Crows, Vultures and in the end, beetles, basically all within a day!

The greatest thing about the whole thing was to see all the Vultures.  The Lappet Faced Vultures are a threatened species with conservation issues throughout it's range.  The fringe of the Namib Desert is one of the areas where these huge, ugly but amazing birds have a chance at a stronghold.  The Vultures should be starting to breed now, and a number of dedicated people are working hard to monitor and protect these birds.

[Special Note]  Fairy Circles - a phenomenon on the eastern fringe of the Namib Desert where areas with Stipagrostis grasses have barren patches a couple meters across, that often form very neat circles in the grass.  As yet the cause is unknown.  Several prominent scientists working on solving the problem consider termites to be the likely cause.
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1 comments:

Pablo (yo) said...

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Thanks,
Pablo from Argentina