{:af}Witrug-aasvoëls in gevaar van uitwissing{:}{:en}White-backed Vulture facing extinction{:}

{:af}Daar is tans slegs 3 000 witrug-aasvoël broeipare in Suider-Afrika oor. Verlede naweek het ’n span by Dronfield-natuurreservaat ingespring om 50 van die aasvoëls in die natuurreservaat vir wetenskaplike navorsing en bewaring te ring. Beryl Wilson, departementshoof van dierkunde by die McGregor-museum en haar span het verlede naweek altesame 50 van die witrug-aasvoëls op Dronfield-natuurreservaat gering vir ’n wetenskaplike projek wat navorsing doen met die doel om die asemrowende roofvoëlspesie van uitwissing te bewaar. Wilson sê: “Die witrug-aasvoël is ’n kritieke bedreigde spesie. Daar is net ongeveer 3 000 broeipare in Suider-Afrika oor. Die afname in die getalle van die voëls word toegeskryf aan indirekte vergiftiging deur renoster- en olifantstropers, van die voëls verdrink in plaasdamme, ander vlieg in kraglyne vas en selfs onveilige veeartsenykundige middels speel ’n rol in die uitwissing van dié voëlspesie.” Wetenskaplike navorsing bring hoop vir die spesie Wilson en haar span gebruik moderne tegnologie soos drones en lokval-kameras wat dit moontlik maak om die voëls en onder andere die impak van aanvullende voer te monitor. “Ons merk die kuikens met ’n sigbare merker, met helder kleure, sodat ons span die voëls kan monitor wanneer hulle begin vlieg en die nes verlaat. Die merker, ’n staalringetjie, wat ons in ons navorsing gebruik, is gedruk met ’n unieke identifikasienommer en is op ’n internasionale stelsel baseer. Die ring word nie weer afgehaal nie en sal gedurende die voël se lewe geheg bly. Die duursaamheid is krities omrede baie voëlspesies geweldige lang afstande vlieg wanneer hulle begin vlieg. Indien ’n voël elders in Suider-Afrika dood of beseer gevind word, word die unieke nommer aan The South African Ringing Scheme rapporteer. Hierdie inligting word dan herlei na die persoon wat die voëls gering het, wat dit dan moontlik maak om die beweging van die voëls te monitor. Ongelukkig is dit oor die algemeen eers wanneer die voel beseer of dood gevind word, wat die ring gelees word. Met die geweldige sterk son in Afrika is die lewensduur van die ring sowat agt jaar voor dit afbreek en verloor,” verduidelik Wilson. Oor die 100 neste lewer net 50 neste kuikens “Dit verg twee volgroeide ouers om die kuikens te versorg totdat hulle die nes verlaat. In 2018 was daar net oor die 100 neste met aktiewe broeipare in Dronfield-natuurreservaat. Slegs 50 van die neste het wel kuikens gelewer wat die nes verlaat het. Dit neem tussen vyf en agt jaar vir die witrug-aasvoëlkuiken om puberteit te bereik. Daarom is daar ook jonger voëls, wat nie broei nie, in die area te vind. Soms kry ons ook ander beskermde of bedreigde spesies roofvoëls wat in die ou neste van aasvoëls ingetrek het/ Ons gebruik altyd so ‘n geleentheid om hulle dan ook te ring vir navorsing,” sê Wilson. “Die span bestaan uit drie hoof afdelings, ‘n boomklimmer, twee leer-manne, die emmer-hanteerder en ’n opgeleide voëlringer.  Elke lid van die span het ’n spesifieke taak waarvoor hy verantwoordelik is. Die opgeleide hanteerder, met die nodige ervaring om met roofvoëls te werk, klim in ’n boom waar hy dan die kuiken in ’n emmer afhys tot op die grond. Een persoon hanteer die emmer terwyl die ringer die kuiken met ’n ring op die regter klou en ’n merker op die vlerk merk. Die kuiken word dadelik in die nes teruggeplaas. Die hele proses word gewoonlik binne 15 minute afgehandel. Daar is ook soms ’n veiligheidsspan wat verantwoordelik is vir ons veiligheid wanneer ons in areas werk met gevaarliker wilde diere soos renosters, buffels en slange. Ons poog altyd om elke kuiken te merk, maar soms is hulle nog te klein of reeds te oud,” verduidelik Wilson. Kanse sewe keer beter om ’n witrenoster te sien as ’n witrug-aasvoël Wilson sê: “Daar is vandag meer as 20 000 witrenosters in Suider-Afrika. Die bewaring van die meerderheid word goed bestuur. Terwyl die spesies die risiko dra om in die wild uit te sterf, is dit onwaarskynlik dat ‘n spesie heeltemal sal uitsterf. In die toekoms kan individuele renosters na reservate van veiligheid geneem word waar hulle weer in hulle natuurlike habitat gesien kan word. Maar volgens statistieke is jou kanse sewe keer beter om ’n witrenoster te sien as ’n witrug-aasvoël.” Te danke aan vrywilligers en ondersteuners “Ons wil die talle plaaslike vrywilligers bedank wat ons span jaarliks uithelp en ondersteun. Die jaarlikse byeenkoms, om die voëls te ring, sou ook nie sonder die hulp en ondersteuning vanaf die Hawk Conservancy Trust, UK, Gauntlet Trust, UK, Puy du Fou Bird Park, France, die McGregor-museum en De Beers moontlik gewees het nie,” bedank Wilson. {:}{:en}

Currently there are an estimate of only 3 000 White-backed Vulture breeding pairs left in southern-Africa.  In October 2018, a team spent the weekend ringing birds of prey on Dronfield nature reserve for scientific research.

Beryl Wilson, head of the zoology department at McGreggor museum along with her team managed to ring a total of 50 vultures during their weekend long operation.

Modern technology and scientific research brings hope for the specie

“The White-backed Vulture is a Critically Endangered species with an estimated 3 000 breeding pairs remaining in the southern African population. The decline in numbers is being attributed to accidental poisonings or drowning in farm dams, unsafe veterinary drugs, electrocutions and collisions with power line structures, and mass poisonings by rhino and elephant poachers. Our research is addressing this, as well as many other factors such as juvenile mortalities, the use of modern technology (like camera traps and drones) in monitoring, the impact of supplementary food, etc. By visibly marking the chicks before they leave the nest, our teams hope to be able to monitor these birds once they fly,” explains Wilson.

“The steel rings are uniquely numbered and are an internationally-based recognised marking system and stays on the bird for its entire life.  This is important because many species cover significant distances once they fledge. Any bird that is found dead or injured in the southern African region will be identified by this number and reported to SAFRING.  This information will then be relayed to the person who ringed the bird. This allows us to track movements of birds. Unfortunately, the opportunity to read the number on the ring only happens once the bird is dead or injured. This is the reason why we use brightly coloured wing markers too.  These numbers are highly visible and allow us to monitor bird movements whilst the animal is still alive and well and travelling about. However, the African sun is very harsh and the markers will eventually break and fall off, usually after about 8 years,”

100 nests only deliver 50 chicks

“It takes two mature birds to raise the chick. In 2018 there were just over 100 active nesting attempts. Of this number around 50 nests will produce chicks that fledge. However, most birds only reach sexual maturity between 5-8 years so there are also a few younger, non-breeding birds in the vicinity too, as well as visitors to the Dronfield Monitoring Site where the birds are given fresh carcasses as a supplementary food resource,”

“The aim of this specific project is to ring vulture chicks, but often we see other raptor (birds of prey) species that utilise old vulture nests or are simply chanced upon whilst we are in the field. Since raptors are all protected or threatened species, we will always take the opportunity to ring these birds too if possible,”

“Each tree containing a nest is quickly climbed by professional raptor handlers with good climbing skills. Most trees are climbed in a few minutes.  The chick is retrieved from the nest by placing it in a bucket and lowered to the ground crew. Each person in the crew has a specific job to streamline the process. The chick is then weighed and measured. A ring is placed on the right leg and if the chick is old enough, fitted with wing tags. The bird is then quickly returned to the nest. The whole process takes less than 10-15 minutes usually,”

“The ringing team usually consists of a tree climber, 1-2 ladder men, a bucket handler and a qualified ringer / researcher. Sometimes there are additional members who are apprenticing or simply observing,”

“The most important priorities in the team are keeping everyone safe. Some areas we work in have dangerous wildlife (rhino, buffalo, snakes etc) around us.  Thereafter, the most important thing is to work quickly and efficiently so as not to unduly stress the chick or its parents,”

“We always try to ring every chick, but some are too small (or still an egg!) or already too big.  We can return to ring smaller birds a few weeks later, but with larger birds we often leave them alone or risk them jumping off the nest before they can fly properly,”

Chances of seeing white rhino 7 times better than seeing a White-backed vulture

“Currently there are well over 20 000 white rhino left in southern Africa.  The majority of them are well-managed. Whilst the species are at risk of going extinct in the wild in the short term, this species is very unlikely to become fully extinct. In the future, individual rhinos will be returned to safe sanctuaries where we will be able to view them in their natural environment again.  However, statistically-speaking, it is now 7 times easier to see a rhino in the wild than it is to see a White-backed Vulture (except of course if you are lucky enough to live in the Kimberley area!!). It is not possible to manage vultures like we have been able to with rhinos, and yet they are critical ecosystem protectors. Without their clean-up skills, the breakout of diseases like rabies, botulism and anthrax has the potential to cripple our ecotourism, farming, game farm and conservation industries. More people need to be aware of the threats facing this extraordinary species,”

Project not possible without volunteers and supporters

“Every year, are teams are supported by locals helpers, too many to individually name. However, the annual ringing event would not be possible with the teams and support from Hawk Conservancy Trust, UK; Gauntlet Trust, UK; Puy du Fou Bird Park, France; the McGregor Museum and De Beers.”

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