drought

Rain!

There is a great song by Lady Blacksmith Mambazo called Rain, rain, beautiful rain[1] that, as many of their songs, I strongly recommend! But it is only when you have two successive extreme dry seasons such as the ones we have gone through in Zimbabwe that you really understand the song!

I already described the seriousness of the drought at the Kruger National Park[2] and things are equally bad further north, in Zimbabwe and Harare where we are.

When we bought our house in the 90’s, we had a good borehole as well as water from the Harare Municipality. Today, the latter is erratic and, as a consequence, over the years many people have sunk boreholes and now there are thousands. As a result, the underground water table is no longer where it was and, probably the deepest end of our own old borehole is 30 meters above the water level! We have dug for water four more times since the original hole dried early in the XXI Century but we have only managed to extract grey stone dust!

Following our failures with various reputed rhabdomantists, in 2013 we decided to change our water management strategy. We gradually moved from water-thirsty plants to succulents and cacti and we buy water from the many suppliers that bring it to your house. Our swimming pool is now a water reservoir -and toad breeding ground- that we fill with the rainfall from the roof of the house (when it rains!) and take showers standing on a basin to collect and use the grey water for watering a few selected plants!

The availability of water is gradually decreasing and many of our plants and trees are no more and others are just surviving from year to year. We have lost pecans, almonds, mulberries and avocados to mention a few. Luckily, we still have a few fruit trees left although their production is near zero. The indigenous trees are still doing well, despite the clear impact of global warming.

But enough of bad news as the rains have just arrived a few days ago, precisely on 10 November. You remember the date now as rain is becoming really critical!

As usual, just before the rains our children’s leopard tortoise “George” (or Georgina?) made an appearance only to disappear again soon afterwards, as usual. In addition, the chameleons materialized out of nowhere, following their own clock, just before the rains. At this time the number of birds increased dramatically as drinking water was really scarce. Miraculously, as soon as the rains came, many species disappeared and we remained with the resident ones that are here the year round.

Another amazing phenomenon is the “greening” speed of the brown grass in our “lawn”! I can assure you that it becomes green in a few hours after the first rain drops. I often think that it is like watching lyophilized grass being reconstituted in front of one’s eyes!

Together with the greenery some interesting insects appear. Among others, the termites immediately start preparing their chimneys and, although they wait before “exploding”, they do so after a couple of days with when they detect that the ground has reached the adequate humidity for them to dig themselves.

The millipedes[3], known locally as tshongololos[4], are the next to make an appearance after spending the dry spell in chambers dug underground. They appear in all sizes, from 2-3 cm to 10-12 cm and are very fond on fruits and cucumber. They live up to seven years in the wild and they need to moult frequently as their calcified exoskeleton does not expand. They have about 270 legs and they carry some specialized mites[5] that clean their bodies.[6]

Apart from the animal life, the rains also create an explosion of colour as the plants and trees suddenly revive. The show starts with the flowering of the exotic jacarandas that turns Harare purple just before the rains. Soon the time of the flamboyant trees come and, the moment the rains start, the frangipanis become really outrageous not only in terms of colour but also by adding their wonderful scent to the garden.

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If the rains are good, our garden will become so green that it will make you forget the drought until next year when we hope that we will have a “normal” one although these are nowadays the exception!

 

[1] If you wish to hear it, it is at this link: https://www.youtube.com/watch?v=iUH7PM0-cpI

[2] https://bushsnobinafrica.wordpress.com/2016/10/03/hippo-drama/

[3] Subphylum: Myriapoda; Class: Diplopoda.

[4] It means “steam train” in the local language.

[5] Neomegistus julidicola Trägärdh 1906 (Acari, Mesostigmata)

[6] They are extremely interesting creatures and, if interested, you could read more about them here: http://www.earthlife.net/insects/diplopoda.html

Cool birds

October is usually Harare’s hottest month with a maximum and minimum temperature averages of 29oC and 15oC respectively[1]. Surface water is very scarce so the garden birdbaths surprise you with their visitors.

Among the guests there are a few small birds of prey that are not “regulars” but that come sometimes: the Lizard Buzzard (Kaupifalco monogrammicus) and the Gabar goshawk (Miconisus gabar).

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The Lizard Buzzard standing in the water.

While at the water I noted that they both behaved in a similar fashion. Apart from drinking (the Gabar Goshawk also bathed), both species spent a long time (over thirty minutes two or three times a day on the days observed) standing on the water baths during the hot hours of the day, around midday.

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The Gabar Goshawk standing in the bird bath, having had a bath.

Was it a coincidence or did they find relief by the freshness of the water in their legs?

I subsequently learnt that birds lower their temperatures through a variety of different mechanisms[2]. The bare skin on their legs and feet helps them to dissipate heat. Water birds stand in the water, presumably to enhance the cooling[3]. Some birds such as vultures and storks also use urohidrosis, the habit of urinating/defecating on their bare legs to cool down by evaporative cooling.

It seems likely that both birds were using the water of the bird baths to cool down their legs and feet and in this way, as the water birds, increasing the cooling effect of their bare skin.

Interestingly, since I wrote these observations[4], two more birds of prey had come and both species had stood with their feet in the water: an African cuckoo hawk, (Aviceda cuculoides) and what I believe to be an African Marsh Owl (Asio capensis)[5].

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The more recent observation of the African Cuckoo Hawk (landing on the water) and the African March Owl below. These  4 pictures were taken with a Camera trap.

[1] World Weather Online 2016. Harare Monthly Climate Average, Zimbabwe. Accessed on 10/10/2016. http://www.worldweatheronline.com/harare-weatheraverages/mashonaland-east/zw.aspx

[2] Mayntz, M 2016. How Do Wild Birds Keep Cool in Summer? Accessed on 10/10/2016. http://birding.about.com/od/birdingbasics/a/howbirdskeepcool.htm

[3] Shriner, J 2012. 15 Unusual Ways Some Birds Beat the Heat. Accessed on 10/10/2016. http://www.birdinginformation.com/15-unusualways-some-birds-beat-the-heat/

[4] de Castro J. (2016). Feet bathing as a cooling down mechanism in two species of birds of prey. Biodiversity Observations 7.77: 1–2. URL: http://bo.adu.org.za/content.php?id=270. Published online: 22 October 2016

[5] Identification to be confirmed as the pictures of the owl have been taken with a camera trap late at night.

Hippo drama

The drought that Southern Africa is experiencing this year was evident already during our visit to Mana Pools in September. Despite the Zambezi River providing sufficient water, grazing was the main issue as the riverine pastures were very low and the patches of green left were those that are inedible.

Browsers and grazer/browsers were still in good shape but large grazers such as hippos and buffalos were already walking longer distances to get to areas that still had grass cover and these were dwindling fast. The hippos’ normal timetable was visibly altered as we “bumped” on several walking far from the water during the mornings and afternoons when, during normal years, they are in the water or sunning themselves by it.

Despite the Mana Pools “warning” the situation we found in the Kruger National Park (KNP) -Lower Sabie and Satara areas- was worse than expected. According to Swemmer (2016)[1] rainfall at Phalaborwa, one of the KNP’s camps, during 2014-15 was 255mm (the long-term average being 533mm) and the 2015-16 figures are extremely low. Two consecutive years of very low rain, combined with very high temperatures is regarded as rare and extreme. It is even likely that this drought will be the most severe since records started to be collected in 1954!

Different views of a very dry KNP (pictures by Mabel de Castro).

The consequences are there for all to see!

In the dry season the park usually has reasonable grass cover. This year there was almost no grass to be seen! The consequences of this could be immediately seen as few live hippos remained in the Lower Sabie River and the nearby Sunset dam. The ones we found looked rather strange and rather long-legged as their normally bulging bellies had shrunk enhancing their legs’ length! In addition, their skin hanged in folds, a consequence of their loss in body condition.

I regret that some of the pictures are disturbing but I need to show what was taking place.

We also noticed that the hippos did not move much and grazed on whatever they would find near the water bodies. As grass was scanty, they would just gradually weaken and die. Buffalo were also having a rough time and we only saw small groups looking thin. Interestingly, in some areas, both hippos and buffalo were doing better.

It is clear that the drought will have a severe impact on the animal population of the park but also on the vegetation cover as we also saw dry or drying trees that were also damaged by elephants searching for their own food. The re-establishment of grass, shrubs and trees will probably take years. The same applies to the animal populations that may not reach previous levels if the observed drier conditions become the norm in the future. In addition the drought will also accelerate soil erosion and modify the watercourses and other water bodies. Interestingly and somehow alarmingly, this is the first time that no Mopane worms have been recorded since surveys began in 2009 (Swemmer, 2016).

Trying to be optimistic about the future, it is possible that the current dry spell will have some beneficial impact by fine-tunning the situation to a future drier climate by reducing the herbivore populations while allowing vegetation to recover and, in a longer term, prevent overgrazing and environmental degradation.

Independently of the various possible interpretations of the impact of the drought on the environment, it is clear that even if the rains would come now, more animals will surely die before food becomes available. These are the ways of Nature, again.

 

[1] Swemmer, T. (2016). The Lowveld’s worst drought in 33 years? Understanding the long-term impacts. Consulted on 2/10/16. http://www.saeon.ac.za/enewsletter/archives/2016/february2016/doc02

 

Big V

Boswell and Big V[1]  are the best-known elephant bulls in Mana Pools National Park. I recently reported about Boswell’s skills to feed on his hind legs[2], a rather unique trick. When we witnessed an elephant feeding on Acacia pods overhead and I reported in an earlier post[3] was Big V so I have already introduced both to you.

Mana Pools this August was extremely dry, as last year the rains were not good. For this reason the area looks more as it does towards the end of the dry season in November than it should be in August: a dust bowl! I believe that the animals are in for a tough two to three months until new rains arrive, if they do as these days weather patterns have changed.

Luckily for most of the animals in Mana the Zambezi River is there and, together with the pools that lend the name to the park, they provide water and fodder to keep the grazers going while the trees such as the apple-ring acacia (Faidherbia albida) will supply elephants with browsing. The animals that seemed hardest hit at the moment were the hippos that need to consume large amounts of grass so it was common to see them walking about during late afternoon already far from the water.

While checking in we learnt that lions had been spotted around an area known as Mana mouth. After recovering from the six-hour journey from Harare and, after unpacking and organizing our lodge, we decided to go there as it is close and the sunsets there are usually beautiful, even without lions! We never reach our destination as on our way we found Big V!

With him were, in addition to his usual young male retinue, a young female and its small calf, something unusual as large bulls tend to hang out on their own or with a few askaris[4]. He towered over the lot and he was clearly the undisputed leader of the group.

In an interesting contrast to his dominance over other elephants, Big V is an extremely relaxed elephant that allows the human observer to approach him either in the car or on foot. In contrast, the younger males can be more boisterous and occasionally perform threatening displays and mock charges that remind us that we are dealing with wild animals!

On this occasion it appeared that Big V was doing some “community” work by pulling down branches from an apple-ring acacia. Clearly, for the elephants this was the equivalent of eating at a Michelin-starred restaurant!

Although Big V was not standing on its hind legs “Boswell style” it stretched and reached high up the tree, to a height the others could not. As a result of its efforts large branches were brought down showing a great dexterity with his nose (it is easy to forget that he was breathing while doing this!) as well as the damage elephants can do to trees!

He will then fed on them, including the main branches, some of which were really thick! While Big V was eating, the other elephants were eager to collect any fallen pods or small branches but from a distance as Big V’s belly rumblings were sufficient to keep them all at bay! Well, not all…

The small female and her calf approached the feeding giant ignoring his rumblings. Expecting some rebuke we were surprised to see that they slowly got closer and closer  she started to steal bits of the branch to feed. The calf was also allowed into Big V’s inner circle and managed to pick some scraps. The large bull completely ignored them!

 

DSCN0022 8.49.54 PM copyAt one stage, the female even took bits of the branch from Big V’s mouth!

The reasons for this closeness I ignore but it was unexpected and we spent a few minutes watching how it developed. Spellbound with these interactions, we forgot about the lions and when the light was fading we returned to our lodge still talking about what amazing creatures elephants are!

 

[1] This elephant has a large v-shaped notch on its left ear.

[2] https://bushsnobinafrica.wordpress.com/2016/08/17/boswell/

[3] https://bushsnobinafrica.wordpress.com/2015/10/14/elephant-overhead-and-it-was-not-dumbo/

[4] From Arabic, an askari was a local soldier serving in the armies of the European colonial powers in Africa. It is also used for security guards and the young bulls that accompany large bull elephants.