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Monday 21 January 2013

"U" is for Unknown





CCF has carried out a number of camera trapping surveys, and also maintains a network of cameras positioned for ongoing monitoring of the wildlife on our land.  While we are mainly focused on cheetahs, there are many other species out there, and the cameras will trigger no matter what passes them by.  In this series of weekly blog entries, I will use these pictures to illustrate some of the wealth of animal life in Namibia - one species per week.  I hope you will enjoy seeing a little more of our world here in the bush.

U is for… Unknown!

With every camera trap survey, there are always some pictures that we just cannot identify.  In some cases it is because the animal is too far away, especially at night.  In others, it is too close, so much so that we get an extreme (and unfocused) close-up of the hide.  In still more cases the animal is moving too fast, or just catches the edge of the frame and all we see is a tiny part of a leg or tip of a tail.

Different camera traps react in different ways, and have radical differences in performance.  Some have a very narrow field of view, others are very wide.  Some react slowly, the more expensive ones react faster.  A few see colour at night, while most use infra-red LEDs to illuminate the scene and therefore produce purely black and white images.

The basic theory however is simple.  The vast majority of camera traps work in the same way as motion sensors in many burglar alarm systems, by tracking a warm body moving against a colder background.  They are generally ineffective in the desert because the ambient temperature is often similar to body temperature, and also cannot detect reptiles such as crocodiles while in water. 

To avoid running through batteries at a fast rate, cameras generally wait in standby mode with just the motion detector active.  When that is triggered, the camera powers up and take a photo.  In some cameras it can mean a delay of several seconds during which time a fast moving animal may have exited the frame.  There is also a further delay while the first image is processed by the camera before it can take a second image.  This can be more than 15 seconds, which means that if there is a coalition walking past, you'll only get the lead animal.



As I mentioned above, night time images are generally illuminated using IR LEDs, thus avoiding animals being spooked by the bright glare of a regular flash.  LED flashes also recharge faster than conventional flashes, so multiple pictures can be taken as rapidly as the camera can process images.  The downside, however, is a reduced distance over which animals can be illuminated.  Many cameras can only light up an animal up to 10m (33 ft) away, with the best reaching out to double that. 

Our initial deployment of cameras used the Bushnell Trophy Cam which is a good middle-of-the-range camera trap, and probably the best you can buy for $200USD each.  Over time, however, we've seen quite a high failure rate of these cameras in the harsh conditions of the Namibian bush.  All of our cameras are deployed continually for years at a time in bright sunlight, torrential rain, and temperatures ranging from a few degrees below 0C (32F) up to 40+C (104+F).  Some are knocked by passing antelope, played with by tenacious baboons, chewed on by hyena, or infested by ant colonies.  Protective metal security boxes help extend their lives, but even with those they are far from invulnerable since the most delicate parts, the lens, sensor, etc, have to remain exposed.

Taking the lead from the Smithsonian Institute, and several other large research bodies, we have been slowly switching over to cameras manufactured by Reconyx.  They are built to much more exacting standards, and have proven much more reliable.  In addition, they are significantly higher performance cameras with lightening fast trigger speeds, and almost as rapid processing and recovery times.  In every performance category they outperform the competition. However, this comes at a price.  The basic model is $450USD, with others in the range costing up to $650USD. 

Far fewer unknown images are recorded by our small group of Reconyx cameras, and most of those occur at ranges where cheaper cameras would have picked up nothing at all.  Ideally we'd like to switch over entirely, especially as the older cameras die, but I suspect the cost will force a compromise.  Hopefully over time however we will slowly reap the rewards that faster, more reliable, and longer ranged cameras will bring.




Monday 14 January 2013

"T" is for Termite!




CCF has carried out a number of camera trapping surveys, and also maintains a network of cameras positioned for ongoing monitoring of the wildlife on our land.  While we are mainly focused on cheetahs, there are many other species out there, and the cameras will trigger no matter what passes them by.  In this series of blog entries, I will use these pictures to illustrate some of the wealth of animal life in Namibia – about one species per week.  I hope you will enjoy seeing a little more of our world here in the bush.

T is for… Termite.  Technically we only have photos of termite mounds, but I hope you'll like the entry all the same.

There are several hundred termite species in the area, none of which are listed on the IUCN redlist.  At CCF we are lucky enough to have fungus-growing termites, from which we harvest a small number of the large mushrooms produced (typically 30cm diameter) to supplement our own table at mealtime. 

These termites feed predominantly on vegetable matter, and can be highly damaging in areas where crops are grown.  Here, however, they have ample food sources amongst natural vegetation, although they do sometimes consume wooden fence posts.  Elsewhere in the world, termites have been known to burrow through all sorts of building materials including concrete, and annually cause billions of US dollars of damage.

The mounds created by termite colonies hereabouts generally range in size from 1-2m, although I know of one that is around 4m.  What is seen on the surface is only about 25-30% of the total mound size, with the rest buried beneath the surface.  Air temperature within and without is about the same as the surrounding temperature, although it is believed that the maze of tunnels may help with air purity within the colony.  The queens can be found in large chambers underground, and many species mate for life, each with a single breeding male.

Most other insects are repelled either by soldier termites, or via a system of 'chemical' warfare with some species able to produce powerful insect repellants that are dispersed through the nest.

Termites are high in protein, even more so than beef, and are considered a delicacy in many countries, including Namibia.  Fried termites taste rather like roasted peanuts.  In other parts of Africa, termite flour is made, and even termite stock cubes. 

Although much research is still needed, termites do not appear to be in any way endangered, with numbers estimated to be either stable or in some cases increasing.

A cheetah standing on a termite mound