bats

Safari to Zambia

Sometime ago our friends Lola and Frank, yes, the same friends we shared our safari to the Mabuasehube area of the Kgalagadi last year [1], invited us to join them for a safari in Zambia. Among the items in the agenda were visits to Kasanka National Park and the Bangweulu wetlands. The latter has been in my wife’s bucket list for 30 years, since our time in Zambia. I have somehow resisted this idea but I was now cornered and agreed, although rather reluctantly. I argued against it on the following grounds:

(i) We had visited Kasanka in the 90’s and it failed to impress at the time;

(ii) It was too early for the fruit bat migration (although I accepted that the rare Sitatunga) and,

(iii) It was too late for the Shoebill stork sightings in the somehow dreaded Bangweulu swamps.

My objections quickly dismissed, we were on and I joined in with the needed arrangements and we departed in early October, as planned.

As the experience we underwent was rich and varied, I will present it in three main sections covering Kasanka National Park and our return after the Bangweulu wetlands, the search for the Shoebill stork in Bangweulu and, finally, our findings at Bangweulu. I will also post smaller observations, including the already posted “Ticks from Trees”.

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Map of Zambia showing lake Kariba and Siavonga in the South and Lusaka (large pebble).   The kidney shaped seed indicates the Congo Pedicle that divides Zambia into two lobes. The tipof the porcupine quill shows the area where we drove next to the DR Congo. The pear-shaped and red seeds indicate Kasanka NP and the southern part of the Bangweulu swamps, where we were.

[1] See: https://bushsnobinafrica.wordpress.com/2018/01/09/camping-dangerously/

Homely bats

In my earlier post I mentioned that we built some bat houses. The idea started with my daughter that somehow is very partial to bats. Together we had observed these unique mammals flying around in the farm at dusk and we thought we could attract them into small houses to avoid them getting in our roof.

We Googled for bat houses or bat boxes and found a large number of ideas. Finally we settled for a simple design taken from a page such as http://picphotos.net/plans-for-building-a-bat-house-to-control-bugs/ and built one as a test case adding our own modifications such as the addition of an inner layer of cork for insulation against the cold and a piece of cloth at the bottom as a landing pad.

A few months later when we returned to Salta, we were delighted to note that about half a dozen bats had moved in! Being ambitious I built a second house following the same concept and the well-known premise “if it works, do not mend it or improve it”! Again, it got inhabited fairly soon after opening its doors to the bat community.

After a couple of years I noted that the first box only had one bat left in residence and I thought “they are clever and moved to the newer house and probably a grumpy old bat was left behind!”

Then a few days ago I noted that the last resident bat of the old box had gone. Its inner cork lining had detached from the sides and it was probably interfering with the bat movement so I decided to remove it to have a look and re-position the box at a better place in relation to the house and the prevailing winds. While unhooking it I noted that the bat was still there but hanging on outside the box and that for this reason I had missed it.

After opening the box, when I pulled the cork lining I disturbed a number of bugs that, when I exposed them to the light, rapidly withdrew to the darker recesses of the box. “Hmm, I thought, negative phototropism”, remembering my high school days!

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The old box opened for servicing. One of the walls have been removed to show the cork lining. The bugs were underneath.

Thinking that the situation was worth further investigation I prepared to catch some of them to identify them at a later stage, if possible. While rummaging around the house finding some alcohol, a catching jar, forceps and a brush I was thinking that I had found a colony of pseudoscorpions, really interesting arachnids that I have found earlier living in the bat guano at the Suswa caves in Kenya. I still have the memory of entering the cave with my wife and Paul and finding thousands of bats inside while we walked on their soft guano that was truly hutching with pseudoscorpions!

In the opened bat box there were many bugs but without pincers! I could see clearly different instars, from reddish brown adults to yellowish showing a darker gut content that reminded me of old blood. After a while I could count their legs and decided that I was watching insects and then I realized that they were bugs of some sort! I confirmed my suspicion when I took pictures of them and even saw the eggshells like those of animal or human lice.

I was lucky that my children had given me a set of VicTsing Clip 12 X Macro+ 24 X Super Macro lenses that enabled me to take the 12X to 36X magnification pictures of the bugs with my cell phone.

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I then realized that the bug infestation in the box had reached such an intensity that the bats must had felt very uncomfortable and decided to move out, away from their tormentors!

All this is still hypothetical, as I have not yet identified neither bats nor bugs with any degree of scientific rigour! However, my educated guess is that the bats are Big brown bats (Eptesicus furinalis), based on work done in the area[1].

The identification of the bugs was more difficult as not much is known (and available to me) on bats’ ectoparasites in Argentina! Again Google’s existence proved very valuable. Bat bugs do exist and one species that has been described for the Americas is very similar to the ones I observed. These are the Eastern bat bugs (Cimex adjunctus).

They are closely related to the infamous Bed bugs (Cimex lectularius). So what? you would ask. Well, I made the mistake of informing my wife about this close bat bug -bed bug relationship and she was not amused that I had been “playing” with them. As a consequence I had to shower carefully before I was allowed in bed!

 

[1] Moschione, F.N. (2014). Relevamiento de Fauna. Finca El Gallinato, La Caldera, Provincia de Salta. Informe Relevamiento 2013-2014. 55pp.

The Eagle and the Baobab

Keep reading, this is not a children’s story, despite the title!

I knew this project would be difficult from the beginning as war movies dealing with eagles show a lot of hard work and heavy casualties!

In earlier visits to Hippo Pools Wilderness camp[1] ( and even earlier ones) I learnt that the camp offers a number of attractions for those feeling like trekking. Among these are old ruins, San paintings, several viewpoints a large baobab and various eagle nests. I was aware that both Verreaux’s and Crowned eagles had nested nearby for many years but I had not seen them before.

Aware of this possibility on arrival I enquired about the eagles’ and I was informed that there was also one of an African Hawk Eagle that had a fledgling. I expressed my interest on a walk to the site but later on I was informed -to my regret- that the bird was no longer where it had been seen before. However, before I could feel too bad, I was told that an egg had been spotted at the Crown’s eagle nest and that we could go there instead! I immediately booked a walk for the following morning.

The walking party.

The walking party.

We left about 07:00 hours and walked for about one and one half hours over rather broken terrain and mainly uphill. After going for about an hour we spotted one of the eagles perched a long way away. However, we were advised that the nest was not in that direction but up the hill! It was clearly one of the pair, probably the male eagle scouting for food as these eagles are special in that the male often feeds the female while she incubates.

The first eagle.

The first eagle.

Close-up of the first eagle.

Close-up of the first eagle.

It should be noted that these eagles are not common and rather secretive and as Roberts VII Multimedia Birds of Southern Africa puts it, “Normally chooses the tallest canopy tree in which to build its large stick platform nest”. Luckily I did not know this while our trek was in progress as I was having additional difficulties with my recently acquired hiking shoes that were destroying my toes!

Examining an interesting cave en route to the nest.

Examining an interesting cave en route to the nest.

After another thirty minutes of steep uphill walk, we got to the general area where the nest was. Although I could not yet see it, my companions did and they got excited about what they saw. Eventually I spotted the nest as well as the second eagle perched about one metre above it.

Getting close to the nest meant that our up hill walk changed into a steep climb until we managed to get to a large rock above the nest. From this really great vantage point we could appreciate the situation and observe. We sat down and remained quiet while my toes throbbed, also quietly…

The return of the eagle to the nest and egg moving.

The return of the eagle to the nest and egg moving.

The nest was large, much larger than I had anticipated! Clearly it had been there for a number of years and its occupants had made a good job at building it. It must have been about two metres across and at least one and one half metres deep! This was a large nest for the species as Roberts VII Multimedia mentions an average diametre of 1.5-1.8 m with a height of up to 70 cm but old nests -such as this one- can reach up to two to three metres in diametre and three metres in height as the eagles add new material every year.

By the time we reached the “watching rock” the eagle was no longer there and we (or rather my companions) could see the egg that, on further observation, turned out to be two! While watching the nest the eagle came back and, after turning the eggs with its beak, literally “sunk” over them and stayed there unmoved by our presence for the rest of the time. Crown eagles are large birds reaching a height of up to 99 cm (tail included) being the fifth longest eagle that exists weighing about 4 kg with a wingspan of 1.50 to 1.80 m, comparatively short for the bird’s bulk. Mainly the female incubates for about 50 days and two eggs laid but normally only one chick goes through as siblicide is the norm. Only after 9-11 weeks the new bird is fully feathered and able to leave nest for nearby branches at 110-115 days. Despite its large size, the bird was truly dwarfed by its nest!

The eagle "sunk" in the nest.

The eagle “sunk” in the nest.

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Over 95 per cent of this eagle’s prey are mammals and they have a reputation for being great fliers and being able to take off vertically inside the forest. I was wrong in thinking that they fed mainly on monkeys, as these mammals are only 7 per cent of its diet. Their usual prey are hyraxes and small/young antelope (65 per cent).

We returned to camp from the eagle’s nest via the baobab tree. I have already spent time on these fantastic trees in a recent post on Chitake so I will not waste too many words. This particular baobab has two main visible features: spikes driven up its trunk and a hole that allows you to see the inside and even enter the tree if you are interested and adventurous. Probably the spikes are there to enable people to collect either tree produce or honey but we could not tell.

The baobab.

The baobab.

The large hole.

The large hole.

The spikes.

The spikes.

As we did not carry torches while looking for eagle nests during the day, there was not enough light to undertake a proper examination of the tree’s interior. We saw that there were some sun rays that filtered through small gaps on the roof, where the branches had sprouted, indicating that the top of the tree is not sealed tightly (as I thought) but there are gaps in its cortex. The holes were small and the light was not enough for us to see inside so we appealed to the trick of using the camera flash to look inside.

The inside of the tree. The spikes are seen on the right upper corner. The flying bat (centre bottom) and stationary bats (centre top), The small light spots are gaps on the top of the tree.

The inside of the tree. The spikes are seen on the right upper corner. The flying bat (centre bottom) and stationary bats (centre top), The small light spots are gaps on the top of the tree.

We saw that there were also spikes inside the tree! Although we did not detect any animal presence or smell (particularly the pungent bat smell!) inside the trunk, we took some pictures and, later examination of these, we noticed a small dark spot on its pale brown interior. It was a bat caught in flight! Further observation and enlargement of the pictures revealed other bats hanging from the roof, not in bunches but keeping distance from one another.

Close-up of the bats.

Close-up of the bats.

By the time we finished our observations of the baobab it was lunchtime and hot so we took walked back to camp, my toes still complaining in silence!

Hippo Pools Camp, Zimbabwe, 8 October 2015.

 

[1] https://bushsnobinafrica.wordpress.com/2014/08/29/hippo-pools-revisited-2/