Paarl Data - Two Antelope And A Bird

I've been fortunate to get a good number of camera trap observations for both Duiker and Grysbok at Paarl Mountain Nature Reserve. It provides a great opportunity to compare these two antelope species.

The Common Duiker (Duiker - Sylvicapra grimmia) at Paarl are eager to help

Lets start by comparing the occurrence pattern for both species on the reserve. It is much easier to compare Duiker and Grysbok than it is to compare something like Duiker and Small Gray Mongoose, because if the camera trap is setup to capture photos of a Duiker then it will also capture a Grysbok, but not necessarily a mongoose.

From the abundance maps it is clear that the two species overlap throughout most of the reserve. But there are some small differences: The Duiker is a bit more strongly associated with the fire breaks and the Grysbok seem to penetrate the think vegetation more easily. The big difference is the patch at the south-east of the reserve. This area burnt a few years ago and the vegetation in the area is still fairly short. I suspect that the Grysbok is quicker to recolonize such areas. It will be interesting to see whether the same area contain Duiker a few years from now when the vegetation is more dense and mature.

The problem with the using the occurrence map, above as a "distribution map" is that not all areas of the reserve was sampled to the same degree. For example the far south was not sampled at all. To confirm that there is a relationship between Duiker and Grysbok observations I decided to evaluate the data as well.

A Cape Francolin (Kaapse Fisant - Pternistis capensis) a bit unsure about this whole analysis business

I compared the number of times Duiker, Grysbok and Cape Francolin were observed within two days of each other and in the same general area. I included Cape Francolin because it is another very common species and will be captured by camera traps that are setup to targeting the antelope species.

As expected the Duiker and Grysbok show a strong relationship, but surprisingly there is a big difference between how the Cape Francolin relates to the two antelope species. I decided to pull up the abundance map for the Cape Francolin, suspecting that it might illuminate why there is such a discrepancy.

The map explains suggests that both the Grysbok and Cape Francolin are present in the recently burnt area where the Duiker is still absent. The Cape Francolin also shows the trend of being less strongly linked to the fire breaks and readily penetrating the thinly vegetated areas.

Cape Grysbok (Kaapse Grysbok - Raphicerus melanotis) helping capture data during the night shift

The males of both Duiker and Grysbok are the only ones to have horns, making it possible to determine the gender. Both species show the same common trend: The males are either more active or more common when compared to the females. My feeling is that they are more active and not necessarily more common.

I also like to compare the day-night activity patterns of the species. Again both species show more or less the same pattern.

I don't use the actual time, but instead like to use a time of day category. The reason for this is because the length of the day changes a lot between winter and summer. So I devised a way of splitting the day and night into categories based on the time when sunrise and sunset occurs. Doing so shows a subtle difference between these two species: Although the trend remains more or less the same, the Grysbok show an odd spike in activity during the late afternoon. It seems like they become active sooner before sunset and remain active longer after sunrise.

I also like to compare the possible influence the phase of the moon might have on the species. Both species show a very similar trend, but again there are minor differences: For some reason Duiker activity is surprisingly low on nights with a dark moon. The Grysbok pattern follows the expected baseline pattern very well with a slight increase towards the start of the full moon cycle.

The last comparison I want to make in this blog post is the chance of getting subsequent visits of the same species during one day-night cycle. Although the Grysbok is the more common species it is the Duiker that is more likely to have multiple observations in the same day-night cycle.

I really enjoy doing these analysis, and I hope to a couple more of these of the next month or two.

The Grey Buck Of Paarl

Dense vegetation is an important requirement for Cape Grysbok, and Paarl Mountain Nature Reserve overs plenty of very dense vegetation. It is no wonder that these secretive antelope like to call the reserve their home.

Cape Grysbok (Kaapse Grysbok - Raphicerus melanotis) at Paarl Mountain Nature Reserve

Cape Grysbok can be hard to see in person because of their secretive and nocturnal nature. They tend to hide in the dense vegetation and can go unnoticed, even when you get very close.

Luckily they are still fairly common around the greater Cape Town area and can even be found living close to human development. If you are lucky you can spot one crossing a road or darting for cover as you come around a bend.

Sneaking past the camera trap

Last year I was approached by a company that manufactures camera traps to test one of their new models. I received the camera trap late December and have been using it since then. The camera is the SecaCam HomeVista and the photograph below was take by it.

Young male Cape Grysbok with a very grey coat

I'm planning on doing a longer review of the camera trap at a later stage, but one of the things that stand out for me is the incredibly wide field of view. I'm sure it will be a blessing and a curse in the future.

I had the camera set to take a combination of photos and videos. The video clip below shows the restless youngster on a very windy summers day.

Video: Cape Grysbok walking through the boulders on a windy day

Only the rams have horns and this individual above seems to be still a fairly young male.

The Cape Grysbok is mostly active at night and about 65% of my camera trap observations have thus far been at night.

The white hair is much less visible in this wet female

They are solitary animals and scent mark their territory using the pre-orbital gland (in front of the eye). One of the cameras was lucky enough to catch a Cape Grysbok in the act of scent marking.

Cape Grysbok scent marking on the slopes at Paarl Mountain

The Cape Grysbok is endemic to South Africa and an iconic species of the dense vegetation along the coast and mountain ranges of the south and south-east.

Spotted On Paarl Mountain

It is the middle of summer at Paarl Mountain Nature Reserve and the world is hot and dry.

Paarl Mountain Nature Reserve in January

I've been camera trapping here since August last year and the species list is still fairly small, only about 15 mammal species thus far...

The strangest part for me is that I've yet to photograph a single Caracal (Rooikat). At both Tygerberg and Koeberg the Caracal was one of the first species to get photographed.

To make things even stranger one of my camera traps recently photographed a Leopard, and still not a single Caracal!

The photograph was taken at 6:21 AM in the morning. The sun was already up, but there was still some early morning mist hanging around.

Leopard (Luiperd - Panthera pardus) photographed by a camera trap on Paarl Mountain

I've been seeing possible Leopard tracks and scat on the reserve since I started camera trapping and knew it would be only a matter of time before one was captured by a trail camera.

Even though the odds of encountering such an elusive animal in person is very small, it is great to know they are still around. I love how camera traps enable you to "see" things you would otherwise never be able to see in person.

The camera trap also captured a lot of Grysbok and Duiker at this location. I'm sure these small antelope also caught the attention of the Leopard.

A female Cape Grysbok (Kaapse Grysbok - Raphicerus melanotis) aka Leopard-Food

I didn't find many Grysbok at Tygerberg and Koeberg, but here at Paarl Mountain they seem to be quite common. I'm looking forward to see the total number of sightings increase over time. It will be interesting to compare the data of all the small antelope I've camera trapped in the greater Cape Town area (Duiker, Grysbok and Steenbok).

There are lots of interesting landscapes at Paarl Mountain Nature Reserve

PS.
Paarl Mountain is a popular reserve and is visited by many people on a regular bases. Now, before the masses go crazy about the Leopard, please remember the usual storie of "your life is not in danger, we don't have to kill the Leopard, your kids will survive, etc." apply. If anybody has any concerns then please contact the reserve manager. Remember how fortunate we are to have a member of the "big five" still roaming wild on our doorstep.

The Data Pond

I've been camera trapping on a small farm just outside the town of Paarl (which is situated very close to Cape Town) from January to April this year.

Bushnell camera trap at the farm's pond

The camera trap at the small farm pond in the photograph above got some interesting results. The initial camera trap positioning was fairly good and I got a Cape Grysbok and Water Mongoose early on.

Cape Grysbok (Kaapse Grysbok - Raphicerus melanotis) getting a drink

However the mongoose decided that my camera placement could do with some adjustment.

Marsh Mongoose (Kommetjiegatmuishond - Atilax paludinosus) freelance camera trap adjuster

After the adjustment I didn't get a decent photograph of any more mammals, but the camera did focus on a small part of the bank and as a result captured many photographs of the resident water birds.

Black-Crowned Night Heron (Gewone Nagreier - Nycticorax nycticorax) sneaking past the camera

Many of the photographs had multiple species visible at once and as a result it took a while to capture the data. In the end I recorded 325 observations over the 3 week period. This is a sizable amount, and I was curious whether the reporting feature I recently added to WildLog might show some interesting trends.

First up is a chart showing the number of observations recorded compared to the duration of the observation (using 30 second intervals). The shape of the curve is fairly standard, with a very large amount of very short observations followed by a sharp drop. What I find interesting is that there is a high number of observations extending past 30 seconds and into the 3-4 minute mark. Clearly these water birds at the pond spend more time feeding in a small area, before moving on, compared to more conventional camera trap subjects and locations.

 
Another benefit of getting such a high number of observations over suck a short period of time is that you can compare the exact time the observations were made too each other, without having to worry too much about the change in season, sunrise, etc. In this case the data shows a huge spike in activity between 5:30am and 8:30am.

Looking at the bar chart that maps each time to a relative time of day category (based on season and sunrise) the same trend is visible. Sunrise and early morning is clearly the peek of activity at the pond.

 
The last chart I want to put in this blog post is one showing the number of observations recorded during each 24 hour period. Looking at the chart it seems like there might be a possible pattern: days with high activity are usually followed by days of low activity. I'm assuming this can be attributed to the birds' feeding behaviour. These species will be mostly feeding on plants, small animals, insect, invertebrates, etc. and it makes sense to allow the prey species some time to recover before feeding again in the same area.

Another interesting observation is that the birds would often feed together. There are many benefits to doing so, ranging from better protection from predators, to the fact that the disturbance caused by one bird feeding might make things easier for the other bird to catch its prey. The different species usually don't compete directly with each other for the same food.

The animated GIF below is somewhat on the large size (about 8 MB), but I'm going to try and include it in this blog post because I think it helps to illustrate life at the pond very well. The following species can be seen in the clip:

• Yellow-Billed Duck (Geelbekeend - Anas undulata)
• Common Moorhen (Grootwaterhoender - Gallinula chloropus)
• Cape Wagtail (Gewone Kwikkie - Motacilla capensis)
• Cape Weaver (Kaapse Wewer - Ploceus capensis)
• Black Crake (Swartriethaan - Amaurornis flavirostra)
• Little Grebe (Kleindobbertjie - Tachybaptus ruficollis)

About 20 minutes of bird activity at the pond condensed into a few seconds

For those wondering, in total this set recorded 19 species. The 6 species mentioned above was by far the most numerous visitors.

During my camera trapping excursions I came across a dead Yellow-Billed Duck and was able to get some close-up photos.

Close-up of the wings of a dead Yellow-Billed Duck

The Yellow-Billed Duck is a type of Dabbling Duck and has the grooves along the edge of the bill to help with feeding.

The duck's bill

I'm really enjoying the new reporting tools in WildLog. Even though these findings are nothing strange or ground-breaking I still learn a lot (first hand) from them. It is fun to see the data take shape after going through the hard work of capturing it.

Dozens Of Duiker

I seem to do a lot of camera trapping at places with berg (Afrikaans for mountain) in the name... Maybe it is because most natural areas that remain are situated around areas where human development has been reduced, such as "mountainous terrain".

Earlier this year I hooked up with fellow camera trapper and blogger Jeremy Bolton to place some cameras in his "back yard", the mountains around the Berg River Dam. You can find Jeremy's blog over here. He also offers unique camera trap safaris, of which you can find out more over here.

Berg River Dam near Franschhoek in the Western Cape province of South Africa

In recent history the area has been disturbed by pine plantations and the development of the dam. I always find camera trapping in such areas interesting, to see what species are still around, or have moved back into the area as the natural vegetation returns.

Berg River Dam near Franschhoek

I was pleased to get some photographs of Common Duiker. Common Duiker are widely distributed throughout South Africa, and they differ somewhat in appearance throughout their range. So I always enjoy getting a good photograph of one in a new location.

(1) Common/Grey Duiker (Gewone Duiker - Sylvicapra grimmia) at Berg River Dam in the greater Cape Town area

Nearby (about 80 km away) on the West Coast, just outside Cape Town I photographed a male looking very much the same at the Koeberg Nature Reserve. (Where? Oops, spoiler alert!)

(2) At Koeberg, also in the greater Cape Town area, this male looks very similar to his friend above

About 800 km along the coast in the Eastern Cape province this individual might have a slightly richer colour with darker legs. This photo is from the same camera as the first animal, so that helps the comparison somewhat.

(3) Common Duiker at the Woody Cape near the coast in the Eastern Cape

You can really see the difference when comparing the three coastal specimens in the South to the this daytime photograph taken about 850-1200 km further North and inland from the three previous animals. In the Gauteng province their other common name Grey Duiker now starts to make more sense.

(4) Far away at Suikerbosrand near Johannesburg this individual looks very different

The Duiker in Kruger National Park looks much more like their Gauteng counterparts which are only about 400km way. These Duiker are now over 1 600 km away as the crow flies (in a straight line) from the initial animal near Cape Town. It might be that the Kruger Duikers sport, on average, a longer hairdo but since the length is know to differ I'll need to get my hands on more photographs from both locations to compare.




(5) This dashing lady looks much more similar to the previous animal than the first one

Below is a map of the approximate locations where the above animals were photographed. The numbers correspond with the number given in each photo's caption.

The numbers on the map corresponds to the number given in each of the previous photographs

And now to throw a spanner in the works, I'll wrap up with a photograph of a Cape Grysbok from Berg River Dam. The Cape Grysbok was also a common visitor to the camera traps. They are mostly active at night, but now and again one goes for a stroll during the day.



Cape Grysbok (Kaapse Grysbok - Raphicerus melanotis) looking somewhat sleepy during the day

Balls And Bucks

One of the strangest things I've encountered at Tygerberg must be the golf balls...

A clutch of 15 golf balls I picked up at Tygerberg Nature Reserve

This weekend I picked up 7 balls while doing my camera trapping rounds! I'm starting to think that maybe they are some sort of disguised tortoise eggs? Maybe the tortoises have started to naturalize to the urban environment and found that mimicking golf balls some how increased the survival rate of their eggs... Now, at first that might sound ridiculous, but if you think about it... Golfers often carry many excess balls in their bag. The bag makes an excellent incubator. A golfer will usually select the best ball in the bag when they need one. Now say the egg looks enough like a ball to fool the golfer, but does not look appealing enough to justify actually using the ball? Mmmm... Maybe I should try incubating one of them and see what hatches...

I have a few slightly more extravagant theories, but maybe I should take a sharp U-turn and bring the discussion back to reality: And what better way than talking about Death.

A little snake that didn't survive the fire

I stumbled upon this casualty of the veld fire while looking for camera trap locations about a month ago. It is a little snake that could not escape because it was stuck under the stone. This is the only fire casualty I could find, except for a couple of fried eggs.

OK... before I cock to many eyebrows... The reason for this post: a Cape Grysbok.

A male Cape Grysbok (Kaapse Grysbok - Raphicerus melanotis) sneaking along

This is a pretty nice photograph I got from the Cuddeback. The first week the camera only got Bontebok and Porcupine pictures, but I decided to leave it out a little longer in the hopes of getting the resident Grysbok. I've photographed Grysbok in the same area before, but a large section of this part of the reserve was burnt.It is good to know that it is still around after the burn.

You can clearly see the white/grey speckles that gives the animal it's name, I guess it is because it looks like it is turning grey. Grysbok translates to Grey Buck. Only the males carry horns.

The Cape Grysbok is more or less endemic to the Fynbos region. There aren't really any other medium-large mammal species that are endemic to this region, making the Cape Grysbok somewhat special.

A Grysbok During The Day

One of the antelope species seen less frequently at Tygerberg is the Cape Grysbok. These dainty little antelope are mostly nocturnal, but are sometimes also active during the day (dawn/dusk/cold weather).

The Cape Grysbok (Kaapse Grysbok - Raphicerus melanotis) gets its name from the grey ("grys" in Afrikaans) speckles on its body

I've only manage to photograph them in one section of the nature reserve (near the pond). I'm sure there must be more of them and I'm hoping to find them when I start focusing a bit more on other areas in the reserve.

A regular at most of the cameras sets is the Cape Francolin (Kaapse Fisant - Pternistes capensis)

The Cape Francolin and Helmeted Guineafowl try their best to keep my camera trapping in check and make sure that everything is "legal". They make their presence felt by trying to be on as many photos as possible at as many different locations as they can manage in as little time as possible each day while spending as much time as possible at each camera.

I try to think of them as my most loyal subjects :)

Finaly My First Grysbok

When I started camera trapping here in the Western Cape a was hoping to find many Grysbok. During a year of camera trapping at Kirstenbosch I didn't manage to photograph even one Grysbok. It is true I didn't spend the entire time just looking for a Grysbok, but I did spend some effort in trying to locate one, but with no luck.

But my luck has turned here at Tygerberg. A Grysbok walked past the camera one evening (near the pond). I have been pleasantly surprised with the number and variety of animals at Tygerberg. I really hope they manage to obtain some new land in the near future, because that will provide a lot of breathing space for the animals.

Grysbok (Grysbok) passing by the camera near the pond one evening with the lights from the houses in the background

A few days after this picture was taken I moved the Bushnell camera into the same spot. The Bushnell managed to get more pictures of the Grysbok (thanks to the faster trigger speed). The infrared flash from the Bushnell does not look as good as the natural flash from the Moultrie, but the Bushnell does have a much better trigger speed and is capable of night time videos. The IR flash is also "invisible" and can be useful for certain situations. Unfortunately the Bushnell's lens speed is a bit slow during night photos and the pictures tend to blur more easily.

The Grysbok's eyes are glowing brightly from the flash

One of my main interests are to identify different species occurring in the "study" area, and for that the Bushnell is great.