Tag Archive | zebras

Detecting the right number of animals

This past spring, four seniors in the University of Minnesota’s Department of Fisheries, Wildlife, and Conservation Biology took a class called “Analysis of Populations,” taught by Professor Todd Arnold. Layne Warner, Samantha Helle, Rachel Leuthard, and Jessica Bass decided to use Snapshot Serengeti data for their major project in the course.

Their main question was to ask whether the Snapshot Serengeti images are giving us good information about the number of animals in each picture. If you’ve been reading the blog for a while, you know that I’ve been exploring whether it’s possible to correctly identify the species in each picture, but I haven’t yet looked at how well we do with the actual number of animals. So I’m really excited about their project and their results.

Since the semester is winding up, I thought we’d try something that some other Zooniverse projects have done: a video chat*. So here I am talking with Layne, Samantha, and Rachel (Jessica couldn’t make it) about their project. And Ali just got back to Minnesota from Serengeti, so she joined in, too.

Here are examples of the four types of covariates (i.e. potential problems) that the team looked at: Herd, Distance, Period, Vegetation

Herd: animals are hard to count because they are in groups

Herd

Distance: animals are hard to count because they are very close to or very far from the camera

Distance

Period: animals are hard to count because of the time of day

Period

Vegetation: animals are hard to count because of surrounding vegetation

Vegetation

 

* This was our first foray into video, so please excuse the wobbly camera and audio problems. We’ll try to do better next time…

This is the wet season

### Craig, his wife Susan, and lion researcher Daniel and I went camping at Barafu the other night. These are Craig’s thoughts as we all sat on top of Barafu kopjes, watching the wildebeest out on the plains. ###

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Daniel and Susan sitting on Barafu

The rains have been especially good this year. We are camping at Barafu Kopjes, at the eastern edge of the lion study area. The wildebeest have moved very far east, as I type this, I can hear them grunting loudly. The noise will only reach greater volume in the coming weeks as the rut approaches. The grass is green, the sky is full of rain clouds, and this is really the most glorious time to be in the Serengeti.

Back within the camera trap grid, the grass is getting tall, and Ali has to mow it every time she checks the cameras. There is almost nothing for the lions to eat inside the grid; most of the lions have moved very far to the south and east. This is the happiest time of year for the wildebeest, zebra, and gazelle – they are out on the open plains where they can see any danger approaching. They can easily move off away from a hyena, a lion, and still be in the lush green grass –so short it’s like the fairway of a golf course. For the lions, though, having to shift so far outside of their usual territories, this is a time of uncertainty. They may encounter rivals, unwelcoming territory holders, and so they move quietly across the land, always on edge. Further to the east, across the park boundary, into the Ngorongoro Conservation Area, there is also the danger that our study lions may encounter the Masaai warriors. Several years ago we lost three of our study lions in a wet April like this one.

All the grazers are drawn eastwards by the extraordinary richness of the volcanic soils immediately downwind from the Ngorongoro highlands. Without the wildebeest, the grass would be nearly as tall here as anywhere else, but it is so sweet, that it is mowed right down to the ground. The vistas here are breathtaking; every animal looks as though it’s floating in green space. It’s almost like snorkeling – the bright orange of the gazelle from head to toe, the vivid black and white stripes of the zebra, the dull brown of the wildebeest but in such mass it’s like a living train as the herd flows across the landscape. And lions, when we see them, stand out a mile. Usually they look like the bulls-eye – a large green target with a concentric circle of brown wildebeest around them.

This is the wet season.

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Ali with sausages. Lots of sausages.

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Susan, Daniel, and Ali, preparing a feast.

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Wouldn’t be camping without a campfire.

Have you spotted a zebra today?

This video is from my first research trip to Serengeti in 2009. I bet you’ve already found some photos of zebras at Snapshot Serengeti. Here’s what they look like moving. (And yes, it was quite windy; sorry for the noise.)

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