wing bling Keeping track of raptors

Text by Andrew Jenkins

cross much of southern Africa, the large savanna raptors such as Tawny and Martial eagles, Bateleurs, and a slew of vulture species, have been Asteadily disappearing from private farmland for the past 150 years. Con- ventional wisdom maintains that this is either because these birds are branded as predators of young sheep and goats and are consequently shot or trapped as vermin, or because they are accidentally poisoned in the vicious toxic war being waged by small-stock farmers on their arch-enemies, the jackal and cara- cal. Either way, the resulting unnaturally high rates of mortality are supposedly to blame for the receding distributions of our eagles and vultures. But what hard evidence has ever been put forward to confirm this relationship, and what quantitative support do we have to show for the decades of concerted effort to save these embattled raptor populations, mainly by cultivating empathy for them in rural communities and discouraging the indiscriminate use of poisons by over-zealous farmers? 

markoctober/november anderson 2007 tracking raptors 45 The problem numerical ‘model’ for the remaining kind of work. Less encouraging is that The primary obstacle is ignorance: we southern African population, in a bid to marking studies require from research- How can you contribute? suffer from a lack of reliable, compa- forecast the future for this species in our ers tenacity, continuity, wide coverage lways keep a look out for marked rap- rable and relevant information with region. Obviously, if we could have pro- and follow-up, and plenty of time in Ators. Should you see one, even if you which to practise effective raptor con- duced a reliable model, this would have order to yield meaningful dividends. can’t identify it, take the time to accurately servation, and are woefully ignorant of been a huge step forward. But these sta- These constraints probably explain why record as much as you can about the bird, even the most basic workings of our rap- tistical tools are only as good as the raw so little of this work has been done, and its colour markings and where you saw it. tor populations. Not surprisingly, there- data they are fed, and we ended up hav- why past efforts have failed to persist If possible, use your binoculars (or, ideally, a fore, we are in the dark when it comes ing to use data essential for our model into the present. spotting scope) to check the details of the to understanding how key factors, such from published studies of captive-bred, The practical problems associated marking, even if the bird is perched close by. as survival, mortality and fecundity, are reintroduced Bearded Vulture popu- with maintaining long-term studies With colour-ringed birds, remember to look influenced by potentially controlling lations in Europe, simply because we are probably even more relevant now at both legs, and to accurately record the aspects, such as poisoning and persecu- do not have the baseline information than in the past. The long delay in leg (left or right) and the order of the rings tion, as well as issues like habitat loss, required for our own birds. Hardly an returns on the investment of funding (preferably read top to bottom), remembering food limitation and climate change. ideal way to make critical conservation and effort required to set up a marking that there should always be a metal SAFRING In 2006, I attended conservation decisions! study is an increasingly unattractive ring included in the total combination. With patagial (wing-tagged) birds, remember to sonja krueger workshops on the Bearded and Cape prospect for scientists operating in a vultures, which highlighted for me the The solution system which requires almost instant, ascertain the colour of the tag/s; if there is he answer to both these ques- nature and severity of this problem. If we concede that a lack of good demo- published results. But if we fail to start only one tag, be sure to record on which tions is ‘very little’. We have Both workshops were convened be- graphic data is one of our more sig- up and maintain these studies now, it wing it is and carefully note the four-character no better understanding now cause numbers of the two species are nificant failings, then surely we need is likely that in another 10 years we alpha-numeric code. of the ecology of natural ver- thought to be dropping precipitously, to take the necessary steps to remedy will find ourselves facing even more If possible, photograph the bird and take a sus inflated death rates in big and both were attended by many of the this? For starters, we need to adopt a critical conservation thresholds, and GPS reading of your location and report your Teagles or the demographic effects of doyens of African vulture biology, each more structured, quantitative approach again bemoaning the absence of the sighting either to the relevant biologist work- poisoning incidents on vulture colo- of whom brought a wealth of experi- to raptor research in general. Happily, vital data required to take effective re- ing on the species in question (see page 48), nies than we did in the 1960s and ’70s. ence and wisdom. Yet what struck me the newly formed Birds of Prey Work- medial action. André Botha of BoPWG ([email protected] or This is not to say that the raptor gurus most forcibly about these gatherings ing Group (BoPWG) of the Endangered 082 962 5725) or the SAFRING offices at the of the past were necessarily wrong or was that even when dealing with two Wildlife Trust, born from a merger of Different marking methods University of Cape Town, tel. (021) 650 2422. that the conservation path they forged of our best-known large raptor species, the former Raptor Conservation and Try to report your sighting as soon as possible was a pointless dead-end. But the real- both of which have been the subject of Vulture study groups, has gone a long Cheap and cheerful – there may be an opportunity or a need to ity of our present situation is that many many dedicated scientific studies, we way towards achieving this change in There are two basic approaches to mark- relocate the bird. of our raptor populations are continu- don’t yet have the demographic facts attitude, and has already established ing raptors, with very different practical ing to decrease, and we are seemingly needed to plan an effective conserva- a much better organised and more fo- and cost implications. Both require that no closer to knowing why this is hap- tion strategy for either. cused core of raptor enthusiasts, spread free-flying or nestling birds be secured pening, let alone devising a solution to In the Bearded Vulture meeting, we across the region. This includes an ac- and handled, and this should always turn the tide. tried to develop a computer-generated tive band of ringers, whose work helps be done with the utmost care. Thereaf- to provide answers to population-level ter, the simplest and cheapest method questions. is to use conspicuous, unique markers But the use of numbered, SAFRING which are attached to as many birds in Above Sonja Krueger and her research rings is really about recovering infor- the study population as possible. team at Ezemvelo KZN Wildlife have mation from dead birds. We need to go These markers may be combinations recently made exciting progress in their further than this if we want to turn the of brightly coloured plastic or metal leg efforts to shed light on movements and corner fully: we need to derive informa- rings or, less commonly, plastic patagial survival in young Bearded Vultures. Here, tion from living raptors, to learn about (wing) tags, attached by a pin punched a juvenile sets off on the next chapter of the trials and tribulations of individual through the patagium (an inert flap of its life, all of which will be carefully moni- birds, and to piece the data together to skin which runs along the leading edge tored by Sonja as the satellite transmitter build reliable models of functioning of the wing). In both instances, colour andrew jenkins on the bird’s back relays critical informa- populations. In essence, we need to in- coding may be supplemented by boldly The impressive talons of a female tion back to her. stitute a programme of well-conceived engraved alpha-numeric codes. Raptors Peregrine Falcon, complete with an in- and well-managed marked-bird studies are good options for this sort of work dividually unique colour-ring combina- Right Vaal-Gariep African Fish-Eagle which will enable us to follow individu- because, in general, they are quite large, tion. This bird – red/gold right, SAFRING number 12 (VG12) is measured and has als throughout their lives, discover how conspicuous, relatively easy to locate and metal left – was ringed as an adult on samples taken, just after being fitted with they disperse, when, where and how they can comfortably carry fairly large a territory just north of Cape Town and wing tags and before being replaced in successfully they breed, how they are rings or tags which are clearly legible. was killed in a collision with a car just its nest. affected by environmental variation, Once a reasonable number of birds over three years later. During that time, and how, where and when they die. have been marked, the emphasis shifts she remained on the same territory, Previous page A patagial (wing- The good news is that there are a to searching for and recording them. paired with the same, marked male, and tagged) African White-backed Vulture number of practical, efficient and often There is a premium on getting regular successfully raised seven young. warms up in the Northern Cape sun. relatively cheap ways to carry out this and accurate re-sightings of as many  mark anderson

46 tracking raptors africa – birds & birding december 2007/january 2008 tracking raptors 47 ...we need to derive birds as possible, for as long as possible. models can remain functional for up to Other species which are already the This is where the birding public comes five years), this technique can be used subjects of long-term colour-marking information from living in. Marked-bird studies often stumble at to quickly generate amazingly detailed studies are the Southern Pale Chanting this point because of a lack of assistance information on lifespan, breeding suc- Goshawk, Black Harrier, Black Sparrow- raptors, to learn about and input from a broader audience. Ob- cess and where and how birds die, sim- hawk and Rock Kestrel. viously, more eyes out there looking ply because each tracked individual is The newer, marked-raptor projects the trials and tribula- and reporting translates into more ac- under constant surveillance. are all associated with a BoPWG ini- cumulated information and, ultimately, The big limitation here is cost. Radio tiative to start wing-tagging vultures, tions of individual birds, a more accurate demographic profile. telemetry is labour intensive, and sat- largely driven by the group’s manager, Therefore, it is essential to publicise ellite trackers and the tracking process André Botha. After careful preliminary and piece the data marking studies as widely as possible, are very expensive, so even the best- research on the practicalities of tag ap- and to encourage the birding commu- funded projects can usually only af- plication, product durability, visibility together to build reliable nity and the public to look for marked ford to track tens of individuals at best. and risk to the tagged birds, a number birds and report sightings. Therefore, while this approach may pro- of rehabilitated White-backed Vultures models of functioning vide rapid and in-depth demographic and one Hooded Vulture were tagged High tech, high price data, these may be unreliable because and released in the Lowveld towards populations The other possible option for getting they are sourced from only a small sam- the end of 2005. Since then, custom- accurate information on how popula- ple of the population being studied. ised variants of these tags have been tions work is to use some form of track- Satellite tracking is also constrained used on a wide variety of vultures by ing device. In the past, this would have by the size of the devices currently a number of research teams through- involved the use of radio transmitters available, which are mostly too big and out the region. Although the number but, increasingly, modern biologists heavy for use on any but the larger, of tagged vultures in the environment are opting for the greater ease and ac- wider-ranging birds. However, given the is still relatively low (about 700), there curacy offered by high-end, GPS-linked rate at which this technology is devel- have already been well over 1 400 re- andrew jenkins (2) satellite trackers, and even instruments oping, it seems likely that small, cheap, sightings, many by members of the pub- logical adjunct to our respective pesti- which are linked to the domestic cell- long-lasting satellite trackers will soon lic, which have added significantly to cide studies but, as the two projects phone network. be available, completely revolutionising our understanding of the regularity and progress, we will be building a unique Tracking studies usually focus on the the way we study animal populations. extent of movements by these birds. understanding of the complexities of spatial and habitat requirements of the Meanwhile, the use of state-of-the-art fish-eagle populations. particular animal, but if enough birds satellite- and cellphone-tracking devices These are just some of the research are fitted with tracking devices that are Where are we now, and on small numbers of Cape Vultures in avenues currently being explored in sufficiently long-lasting (some of today’s where are we going? Namibia and in the Magaliesberg, and our efforts to get to grips with raptor Only a handful of the existing marked- on Bearded Vultures in KwaZulu-Natal, populations. While we don’t necessar- raptor studies in southern Africa have is adding marvellous real-time detail to ily want every other vulture or eagle been operational for any length of time these spatial pictures and, in time, cru- you see to be carrying a big, ugly pata- Report your sightings but, encouragingly, with the resurgence cial demographic data will accumulate. gial tag, or every falcon or hawk to be In all instances, sightings of colour-ringed or engraved with alpha-numeric codes to Gerard of the BoPWG and a more quantitative In practical terms, the information po- wearing a ‘bangle’ of colour-rings, we wing-tagged birds can be reported to the Malan ([email protected] or 083 332 1589). approach to raptor work in the region, tential of these techniques for vultures do need to selectively increase the num- SAFRING offices at the University of Cape Town a number of new projects are getting would seem to be both limitless and bers of marked raptors, and we actively on tel. (021) 650 2422, or to the researchers Colour-ringed or wing-tagged Black under way. vitally important for the birds’ future encourage you – the eco-conscious, bird- involved in individual projects. Harriers Some of the older, established projects conservation. friendly public – to look for them and Rob Simmons ([email protected] or 082 include my own work on the ecology of Almost as a by-product of all the ac- report your sightings. These include: 780 0133). Peregrine Falcons on the Cape Peninsu- tivity around wing-tagging of vultures, Perhaps soon we will have colour- Colour-ringed Peregrine Falcons la, which has involved colour-ringing a couple of large eagle projects have marked or even satellite-tracked popu- Please report any sightings of birds to me Wing-tagged Verreaux’s Eagles of both adult and nestling falcons in also included tagging as part of their lations of Bateleurs and Tawnies and ([email protected] or 082 959 9238). In Lucia Rodrigues (signet@mweb.co.za or this population since 1997. In that standard field protocols. For example, Martials, and we will be working to- Top Three newly colour-ringed Peregrine addition, I would welcome any information you 083 325 8881), or André Botha of BoPWG time, I’ve marked more than 350 birds, next time you are fishing on the banks wards conclusive explanations for their nestlings in a pensive mood on their nest can provide on the sex of the bird – females are ([email protected] or 082 962 5725). some of which have been seen as far as of the Vaal River or paddling the rap- range contractions and dwindling num- ledge in the Cape Peninsula. bigger and bulkier and, as a rule, adult females 800 kilometres away, although the ma- ids of the Breede River in the Western bers on private land. With the recent have coarser barring and browner-grey backs Wing-tagged African Fish-Eagles jority of re-sightings have been from Cape, keep a lookout for wing-tagged big push to tag vultures, it’s possible Above A pair of colour-ringed Peregrines than adult males. Mark Anderson ([email protected]. within a 20- to 30-kilometre radius of African Fish-Eagles. Any you see have that we have already taken the first vi- ‘discuss’ the pros and cons of breeding in a gov.za or 082 788 0961), Adam Welz the Peninsula. contributed blood and feather sam- tal steps towards ending what could be Pied Crow nest on a building in suburban Colour-ringed Black Sparrowhawks ([email protected] or 073 162 3887) I’m particularly interested in con- ples to studies of chemical pollution termed ‘The African Vulture Crisis’, a Cape Town. Both birds were less than two Ann Koeslag ([email protected] or André Botha of BoPWG (see above). trasting the fates of urban-living falcons in these two catchments. These are more gradual and discrete process of de- years old when this photograph was taken, or 072 357 0909). with those that spend most of their time being run by Mark Anderson and the mise than its Asian equivalent, but pos- and their rather premature relationship Wing-tagged Cape, White-backed and in the mountains, and in measuring the Northern Cape conservation authori- sibly no less calamitous if we continue was not to last. The female left soon after Southern Pale Chanting Goshawks other vultures effects of climate and habitat change on ties on the Vaal, and by Adam Welz trying to prevent it without hard demo- and took up with a different male, at a Report sightings of birds with coloured rings André Botha of BoPWG (see above). the dynamics of this rapidly expanding and me along the Breede. At present, graphic data at our disposal, and a real more ‘upmarket’ location on the Peninsula population. the wing-tagging is simply a useful and understanding of its root causes.  mountain chain.

48 tracking raptors africa – birds & birding december 2007/january 2008 tracking raptors 49