After nine years of the world’s most ambitious species reintroduction program, once ‘Extinct in the Wild’ scimitar-horned oryx now roam freely in the wild in Chad.
Read here the fifth article of Sandscript 30th issue
The tele-anesthesia and chemical immobilization of wild antelopes that the Government of Chad, the Environment Agency – Abu Dhabi (EAD) and Sahara Conservation strive to conserve falls under the responsibility of EAD veterinarians. The ultimate goal is to safely anesthetize individual animals from a distance to allow veterinarians and researchers to undertake the required procedures. read more
On a routine monitoring patrol in late January 2021, SCF’s long term oryx monitoring team member Habib Ali, who has been with the project since the start, came across an untagged female oryx with a young calf at foot. Judging by the horn development, he estimated the new calf was around one month old and he suspected it has not been encountered before. After entering the observation into the oryx data base he took a good photo of the pair to complete the record. The lack of any tags on the female clearly showed she was herself one of the first generation of oryx born in the wild since the oryx re-introduction project has begun, and now she too had a calf of her own.
But there was more, because the photo clearly showed two distinctive white spots on the face mask of the female. A quick check through the project’s photo library of individual oryx confirmed that the spot pattern exactly matched an oryx we had seen before. It became clear that the new mother is the first of three calves born on Chad to a founder female from Abu Dhabi and released in January 2017. That female, wearing a satellite collar marked ‘36’ in red letters (giving her the rather dull identity code name ‘R36 F’) produced her first calf in March 2018. Logically, but equally dully, the calf became known as R36-01F. More interestingly, although nothing unusual was noticed about her colouring as a new-born, by 3 months of age and still accompanying her mother, two distinctive clean white spots appeared on the face mask of R36-01 as her adult coat colouring developed. Using these spot marks, the team were able to keep track of this wild born female on and off for the first 18 months of her life, but observations stopped in August 2019 – until Habib took his photo of R36-01 with her own first calf on 21 January 2021 – !!
Oryx R36-01F. Photos © Tim Wacher
Whilst gratifying in itself, this anecdote points the way to a number of very interesting questions about the oryx and their reintroduction that the project aims to answer.
March 2018, when our spotted female was born, was the middle of a very harsh and hot dry season. Around 30% of females giving birth in that season experienced calf mortalites. Not of itself unusual for wild ungulates in poor conditions. But evidently R36 F successfully raised her first calf through that period. We also know that through the four weeks after R36-01 was born, the new mother and calf were seen (12 times) always in a group of 3, accompanied only by the adult male R23M. Commonly a new conception occurs as a result of this ‘consortship’ behaviour. But the records show clearly that in this instance, either R36 F did not conceive at all despite the consistent presence and courtship of R23M, or she aborted any resulting pregnancy at an early stage. That is sure because she did not produce her second calf until 15 months later, when she formed a consortship with one of the biggest and oldest founder males, B40M. Based on knowledge of average gestation lengths derived from zoo records, that means the second calf was not conceived until c. September in the late 2018 wet season. But her third calf arrived promptly 8.5 months later, confirming no delay in conception after giving birth in June 2019.
Oryx R36-01 and calf R36-01-01. Photo © Habib Ali
Assessing calf productivity and survival are both key measures of project success. Thanks to EAD’s extensive collaring of founders, the project has good preliminary estimates of successful calf production. But the story of B36 F and her three calves to date illustrate how we are now getting into a position where a deeper understanding of the way season, and year to year variation in conditions may affect this, by analysing across the full set of known individuals over several years. The natural markings of our 2 spotted oryx have allowed the project to confirm one wild-born oryx has herself survived to breeding age. But only because she can be recognised. In order to obtain an estimate measure of the general rate of wild-born calf survival, the project introduced the wild calf ear tagging program in late 2019. Since then (and ongoing), the team have tagged 41 wild born oryx calves. And R36 F’s third calf, probably a half-brother to R36-01, is among them, now wearing the green ear tag G1355. Of course to assess the probabilities of survival to breeding age, we will have to keep looking for and recording all sightings of all these oryx for at least the next 2-3 years as they mature to breeding age. And there will be complications taking account of variation in ‘findability’ of individual oryx, as satellite collars drop and ear tags may fall out. But that is for the back room analysis! In the first instance we hope to record as many cases of known wild-born oryx themselves with calves at foot or forming consortships as possible.
By Tim Wacher, John Newby
The Scimitar-horned Oryx Reintroduction Programme in Chad is a joint initiative of the Government of Chad and the Environment Agency–Abu Dhabi. Under the overall leadership and management of the Environment Agency–Abu Dhabi, on-the-ground implementation of the project is carried out by the Sahara Conservation Fund. In 2019, following a highly successful first phase of activities, EAD generously agreed to develop and fund a second five-year phase of operations. Phase II of the project maintains focus on building the oryx population but also adds new Sahelo-Saharan species to the mix, including the Critically Endangered addax antelope (Addax nasomaculatus), dama gazelle (Nanger dama), and North African ostrich (Struthio camelus camelus).
June 28, 2019. The screening was held under the patronage of Dr Ali Obaid Al Dhaheri, Ambassador of the UAE to China and in partnership with the Environment Agency Abu Dhabi and the Beijing Foreign Studies University.
December 6, 2018. To date, more than 150 captive-bred scimitar-horned oryx have been returned to the wild in Chad’s Ouadi Rimé-Ouadi Achim Game Reserve. This vast protected area was set up in the 1960s specifically for the conservation of oryx and other desert species.
October 5, 2018. The Sahelian plains of Chad have welcomed 40 Scimitar-horned oryx calves in 2018, which were born as part of an Abu Dhabi-sponsored programme.
On June 30, the Smithsonian Conservation Biology Institute (SCBI) welcomed a new scimitar-horned oryx, born to mother Rizzo after she was impregnated by an assisted reproduction procedure in October of 2017. The calf’s arrival marks the first birth of an oryx to be conceived through artificial insemination without the need for risky anesthesia.
April 23, 2018. A timely intervention made by the late Shaikh Zayed Bin Sultan Al Nahyan, the UAE’s founding father, helped reintroduce a wild animal back to the wild, according to a documentary screened in the capital on Sunday evening about an ambitious international conservation project.
Many thanks to Marie Petretto, Tania Gilbert, and Philip Riordan for this article giving a useful overview on the experience of Marwell Wildlife, SCF long-time partner, with antelope conservation in Tunisia and in the Sahara.
Once abundant and widespread Saharan antelopes, such as scimitar-horned oryx (Oryx dammah) and addax (Addax nasomaculatus) have dwindled towards extinction during the twentieth century. Tunisia recognised the dramatic loss of its natural heritage early, and was amongst the first range countries to implement a national strategy to return these emblematic ungulates to their natural habitats.
More recently, a joint project between the Environment Agency-Abu Dhabi (EAD) and the Chad government, with the Sahara Conservation Fund as the implementing agency, led to the release of captive-bred scimitar-horned oryx (SH oryx) from Abu-Dhabi, into the extensive unfenced Ouadi Rimé-Ouadi Achim (OROA) Reserve in Chad, several decades after they were extirpated by over-hunting and habitat degradation.
Since the first release of SH oryx in Tunisia’s Bou Hedma National Park in 1985, and the subsequent Djerba Declaration in 1998, Marwell Wildlife has collaborated in a long-term partnership with the Tunisian Direction Générale des Forêts (DGF) to restore antelopes and their arid ecosystems in Tunisia. Our work has focused on monitoring these animals and their role in the aridland ecosystems. Our surveys address key questions on population viability, habitat use and animal health using a range of techniques including population genetics, biodiversity assessments, and population modelling.
Photos © Chawki Najjar / Marwell Wildlife
In 2012, the EAD convened a team including the IUCN SSC Conservation Planning Specialist Group, the Smithsonian Conservation Biology Institute, RZSS and Marwell, to model scenarios of reintroduction success. The baseline model was adapted from one that Marwell developed for the reintroduction of SH oryx to Tunisia’s Dghoumes National Park in 2007.
Genetic evaluation by EAD and RZSS of the captive population for reintroduction to Chad indicated they would benefit from additional lineages, and in 2015 Marwell transferred 14 SH oryx donated by several European zoos (EAZA) to Abu-Dhabi. Together with SH oryx transferred from North America, they increased the population’s genetic diversity at the EAD. A similar approach to creating genetically diverse founders for reintroduction was employed in Tunisia in 2007, when animals from EAZA and North American zoos (AZA) were released into Dghoumes National Park.
Photos © Marie Petretto / Marwell Wildlife
There are substantial differences between the reintroduction of SH oryx to the large unfenced OROA Reserve in Chad and the smaller fenced protected areas in Tunisia. Unlike the OROA population, those in Tunisia require ongoing management to ensure long-term sustainability. Marwell works closely with the DGF and reserve managers to implement strategies that address issues of limited carrying capacity and small population size. These management strategies are informed by modelling, logistics, and genetics, thanks to generous support from SCF, RZSS, Le Cornelle (Italy), Monde Sauvage (Belgium), and Dublin Zoo (Ireland).
Our team’s success with SH oryx has stimulated similar Marwell & DGF projects for reintroduced addax (in partnership with RZSS, Al Ain Zoo-UAE and San Diego Zoo Global-USA), and the North African ostrich in Tunisia (for more details visit www.marwell.org.uk/conservation ).
Photos © Chawki Najjar © Marie Petretto / Marwell Wildlife
Sadly, many countries do not have protected areas of sufficient size and with enough suitable habitat to support self-sustainable populations of large-bodied animals. Our fragmented population model may be the only pragmatic option that many countries can adopt if they want to see the return of these species. Marwell and the DGF are working to recreate natural species assemblages through management interventions across the network of protected areas in Tunisia, and the results will inform similar projects in other areas. An already tangible output is the Tunisian strategy for “re-wilding” areas that have been intensively overgrazed by domestic livestock.
Tunisia has demonstrated a strong commitment to the conservation and restoration of Sahelo-Saharan wildlife, and Marwell is honoured to partner with the DGF and will continue to collaborate on Tunisian conservation initiatives for the foreseeable future.
M. Petretto, T. Gilbert, P. Riordan – Marwell Wildlife
February 2018: New Oryx Release
75 new scimitar-horned oryx have been flown from Abu Dhabi to Chad on Mid-February, as part of the Chad oryx reintroduction project.
As with each release, the animals are given some time to get used to their new environment ; they will remain in the pre-release pen for a few months. On the wet season, they should be released into the wild to join the oryx already out there.
Again, the team working with the Sahara Conservation Fund was incredible : Environment Agency-Abu Dhabi, Wildlife Service of Chad, staff of the Ouadi Rimé-Ouadi Achim Game Reserve, the Chadian army, the French army in Abéché, the Geyser company for logistics.
The February-March period has then been dominated by a series of new births among the released oryx at the beginning of the hot dry season. Tim Wacher, our expert on the ground, (Zoological Society of London, member of the Science and Conservation Committee) is paying close attention to these births. Assessment of calf production and survival will be key information.
Photos © Tim Wacher / Zoological Society of London
To date 27 wild births have been detected, with more expected. At the end of March 2018, the wild population is at or very close to 105. There are 76 oryx in the pre-release pens comprising 74 delivered from EAD in February 2018.
With new births expected in the days to come, there is great hope to soon have over 200 oryx in country!