The implementation of the programme was preceded by an exhaustive assessment process during which the method was first tested on vultures in captivity to ensure that it is safe for the birds and does not cause any physical harm or impede their ability to fly and forage. After this was confirmed, we also fitted tags to a small sample of nestlings in the Kgalagadi and near Kimberley to see whether this process would cause abandonment of nests or rejection of chicks by their parents. To date, no such negative behaviour has been observed and the extensive number of re-sightings of tagged fledglings subsequently has also backed up our initial observations.
A great opportunity to also test the method on free-flying wild birds presented itself when 16 vultures were saved from a mass-poisoning event that occurred near Hoedspruit in the Lowveld in October 2005. After successful treatment at the Moholoholo Rehabilitation Centre for about two weeks, the 15 African White-backed Vultures and a single immature Hooded Vulture were tagged, ringed and released on the 5th of November 2005, all bearing tags with the alphabetical code A followed by three digits carrying a unique number for each bird. Some of these birds were re-sighted the very next day at the Moholoholo vulture restaurant and all of them were re-sighted somewhere in the Lowveld/Kruger National Park within the first 12 months after they were released. Some of these birds have been sighted more than 200 times over the last four years!
Based on our assessment and the recommendations from vulture researchers elsewhere in the world, the method was approved for general use in the colour-marking of vultures in southern Africa at our Annual Conference in 2006. This method has since been implemented at almost 20 sites across southern Africa, from the Etosha National Park in Namibia, to the Potberg Cape Vulture colony in the Western Cape and the Lowveld in the east. It also includes countries such as Swaziland and Botswana. Zambia is also currently considering the option to join the programme. Each site where tagging is done, has received its own alphabetical code, e.g. B = Magaliesberg-region, W = Kimberley and E = Etosha. It is thus fairly easy to find out where a bird was marked regardless of where it is seen subsequently.
To date, there are more than 1900 marked vultures on our database. Most of these birds were ringed and tagged in the nest at various sites. However, we have also been able to successfully capture and tag considerable numbers of free-flying vultures using a mass-capture technique that was first successfully introduced at the Rare and Endangered Species Trust in Namibia in 2004 and has subsequently been used to good effect at a number of sites in South Africa. At one such an event in February 2007, we were able to ring and tag almost 80 vultures in about 2.5 hours at Moholoholo! This method is however only used outside of the vultures' breeding season so as to minimize stress on breeding birds.
The implementation of this method was also accompanied by a concerted effort to promote the reporting of re-sighting of tagged birds by conservationists and the public over the last 4 years. This has worked extremely well and we currently have almost 7000 records on the re-sightings database with some exceptional information on vulture movements having been obtained. The map below (click on the image to enlarge) gives an idea of some of the records that have been obtained over the last 4 years and reflects the extensive areas that some of these birds cover and move in their search for food, especially in the first few years of their lives.
The longest distance moved by a single bird on record is that of a first-year African White-backed Vulture that was tagged in the nest by Abrie Maritz in the southern Kgalagadi and which was recorded in the South Luangwa National Park in eastern Zambia about 8 months after fledging. This represents a straight-line distance of almost 2000km! Several birds from the same area have also been seen in northern Botswana and the Caprivi in Namibia. On the recent International Vulture Awareness Day on the 5th of September 2009, another fledling from this region (K374) was recorded by a group of vulture enthusiasts at the Kempenfeldt Vulture restaurant near Dundee in KwaZulu-Natal, the first ever recorded movement of a vulture between these two areas!
What these recorded movements underline, is the incredible mobility of vultures and the extensive distances that they can cover in their search for food. This poses special challenges to conservationists who are working to protect these birds and has had a considerable impact on our approach in this regard. The only way to work effectively to conserve these birds in southern Africa and beyond, is to work cooperatively across provincial, national and even regional boundaries and to approach vulture conservation in Africa from a continental approach, involving as many partners and supporters from all the relevant range countries as possible to work towards a common goal: ensuring that vultures and other scavenging birds remain a regular feature of the African skies and landscapes for generations to come.
Other species have also subsequently been tagged, but on a far more limited basis related to specific studies in a particular area. Species that have been tagged in addition to vultures include: African Fish Eagles (Gariep and Breede River systems, N & WCape), Verraux's Eagles (WCape), Secretarybirds (Gauteng, NCape and Free State) and Marabou Storks (Swaziland and Lowveld).
I would like to wish all the fieldworkers well for this season and look forward to participating in some tagging in Zululand and elsewhere in the coming weeks.