 Reference Base  Reintroduction of a captive born white rhinoceros (Cerato... |
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Boeer, M.; Brain, C.; Cantzler. T.; Hamza, H.; Venzke, K., 1999. Reintroduction of a captive born white rhinoceros (Ceratotherium simum simum) to the Etosha National Park Part II: Behaviour in the boma, procedures before and locomotion during the first ten weeks after release and observations from June until November. Zoologische Garten 69: 73-81, figs. 1-6
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| Location: |
Africa - Southern Africa - Namibia |
| Subject: |
Translocation - Methods |
| Species: |
Black Rhino |
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Release of zooborn animal in Namibia - Diceros bicornis. Monitoring of the rhino's locomotion after release
?Kai's' wanderings and his localizations were checked daily during the first two weeks after release either from the ground by car and by hiking through the terrain or from the air by plane. After that time he was localized only by plane regularly twice or three times per week.
Release phase
T'he rhino was released during the morning hours of March 9, 1997. The unusual large amount of people round the boma and the new situation with a few meters of open fence obviously made the rhino nervous. When alfalfa was spread across the fence opening into the outside area as a trail the rhino slowly left the boma after about one hour (Fig. 4).
Obviously a short period of time of finding his bearing followed when he finally headed straight toward the open plains of the grasland west of the boma. Rangers tried to follow the rhino on terrain and by plane. The GPS system proved to be suitable for localizing the animal in a few minutes. After a few hours ?Kai's' speed of locomotion became too fast to be persuited by hiking through the rugged and thorny terrain. For the next three days he was followed by car but thereafter he moved into the flooded south of the National Park area where he only could be localized by plane then.
Movements in Etosha National Park from March 9 to March 25, 1997
During the first week the rhino moved southwards into the wet part of Etosha covering distances of 3-12 km per day. T'hen the rhino changed its main direction and moved northwards. On March 19, it was located near Twee Palms, about 12 km west of Fort Namutoni, after having travelled over a distance of 100 km (Fig. 5).
The second week after release ?Kai' headed towards the northeastern part of the fenced reserve and was seen there several times. In the southern part of Etosha vegetation consists mainly of Mopane (Colospermum mopane) and Competrum forest (Competrum spec.) in addition with a mixed ?bushveld' (Acacia spec., Croton spec., Dichpostachys cinerea) and is a prefered habitat for Diceros bicornis, whereas the northern part consists of wide open grasland plains and ?sandvelds' with wide and flat dune formations and lots of different grass species. This area was presumed to be the favourable location for the white rhinos already translocated, adapted and released one year before this project started.
Movements in Etosha National Park from March 30 to May 25, 1997
A trend for territorial settlement in the northeastern part of Etosha is shown in Fig. 6. The rhino's movements were confirmed to this region. Many tracks were found there and the amount of dung left by him in this area suggests that he has already been staying there for quite a longer period of time. Given enough waterholes and gras in an optimum height for white rhinos, ?Kai' roamed in this part of the park throughout the entire period. Furthermore his movements indicated his ability to find and remember localizations of permanent waterholes.
On April 17, 1997 the rhino was spotted, his condition was excellent. He had lost the collar, which was found two days later at the edge of the Etosha pan. The GPS 1000 implant broke at the end of May. Afterwards data collection of the rhino's movements could only roughly be accomplished by ground patrol and the APU (anti poaching unit).
Behaviour towards humans
Approach by humans up till the end of the dry season was only possible for the rangers during feeding the rhino. Approaching attempts failed completely in the rainy season when ?Kai's' increasing aggression led to attacks. The food then was thrown over the fence.
Until the end of March 1997 calling the rhino by its name provoke its standing motionless and turning ears and head towards the voice, sometimes the rhino approached the caller and sniffed intensively. By the end of May, more than two months after release, calling the rhino did not lead to reaction and approaching had become impossible now. The rhino's flight distance had become noticeably greater.
Sporadic observations of the rhino between June and November 1997
Although regular monitoring had become impossible due to loss of both telemetric transmitters, ?Kai ? was seen once or twice a month by the Namutoni rangers or the APU during the next half year. He was always localized in the area between the three waterholes Mushara, Kameldooring and Aroe, which he used for drinking according to his tracks found regularly at these places. He was always in optimal condition. The tracks investigated gave no hints on critical meetings with elephants or large predators. His tracks were also found on the ?spoors' of an adult female and a 2-3 years old juvenile, which had settled in this area earlier after their transfer from Kruger National Park to Etosha.
Discussion
Behavioural changes as well as other physiological processes during the adaption period in the boma can be a result of a species' specific ability to react in a broad positive way toward climatic change shortly before the onset of the rainy season in northern Namibia. The sudden decrease of activity in the fourth week of stay in the boma may have been caused by suffering from deep skin scratches due to acacia thorns. Either inborn or acquired, the broad trend to increased locomotive activity in the boma and in the beginning of release may have enabled the rhino to find an area most suitable for a grazing megaherbivore in the northeastern part of Etosha within 12 days after travelling over more than 100 km. This area was predicted to be the preferred area for released white rhino. Olfactoric orientation for a potential breeding partner may also have attracked ,Kai' to this area. The region between the three waterholes mentioned above covers an area of about 40 square kilometers and since the rhino's wanderings focus on this area during the last six months, ,Kai' may have adopted these grounds as territory, which provides permanent water supply and large diversity of gras species during the rainy season, biomass sufficient for a grazing hind gut fermenter all year round and the vicinity of potential breeding partner conspecifics. Changes in behaviour toward humans indicated a trend toward increasing feralization after release. The data collected from this case study so far are promising with regard to future reintroduction of ex situ captive bred white rhinos as well as other rhino species to communal or private in situ nature reserves.
Summary
After an intercontinental long distance transfer and an adaption period of about six months, an ex situ captive born white rhino which had been grown up in middle European climate for five years, was released into an area of the natural former range of this species abundaned a century ago in tropical northern Namibia. The rhino was able to find optimal habitat with regard to digestable biomass, water resources, landscape and further reproduction within 12 days after travelling over a distance of more than 100 km. All rhino settled down in the northeastern part of Etosha National Park. The results describe one possible way of performing such transactions and enhance future chances of successful reintroduction of ex situ born rhinos.
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