The World Working Group on Birds of Prey and Owls

The 5th World Conference on Birds of Prey and Owls

Bernd-U. Meyburg, Wolfgang Baumgart  & R. D. Chancellor


In conjunction with the Raptor Conservation Group (RCG) and Vulture Study Group of the South African Endangered Wildlife Trust, the World Working Group on Birds of Prey (WWGBP) held the V World Conference from 4-11 August 1998 in the splendid setting of the ESKOM Centre at Midrand, Johannesburg. Some 250 participants came from all continents to attend the conference, the emblem of which, lending prominence to South Africa, the host country, was a soaring Bateleur Eagle (Terathopius ecaudatus ). To commemorate the occasion, a special set of postage stamps was issued depicting different birds of prey and, during the opening ceremony, an official representative of the South African government solemnly presented framed sets of these to the chairmen of the WWGBP and the RCG.


In addition to the faultless organisation of the ESKOM Centre, other noteworthy contributions to the event were a piece of music specially composed for the occasion and a liberal supply of specially pressed “Lesser Kestrel” red wine, making the conference opening a conspicuous success. During the next few days the participants fused into a well-knit community, many new contacts were established, friendships sealed and ways of co-operation agreed on.


Following the formal opening on 4.8.98, the scientific programme consisted of 14 sessions held concurrently in two separate lecture halls, during which over 130 oral presentations and 35 posters were delivered. Parallel with the World Conference, the 3rd International Raptor Biomedicine Conference was also held at the ESKOM Centre from 9-11 August, 1998. Midway through the conference, so as to make a break and allow participants to relax, an excursion was organised to view a breeding colony of Cape Vultures at Magaliesberg and to visit the De Wildt Cheetah and Wildlife Centre nearby. On this trip it was possible to observe the numerous Cape Vultures and occasional White-backed Vultures (Gyps coprotheres and G. africanus), together with Black and Fish Eagles ( Aquila verreauxii and Haliaeetus vocifer), Milky Eagle Owl (Bubo lacteus) and Pearl-spotted Owlet (Glaudicium perlatum), not to mention other characteristic examples of the South African avifauna. That same evening the participants were invited as guests to a splendid banquet held to celebrate the Silver Jubilee of South Africa’s Endangered Wildlife Trust.


In the immediate vicinity of the ESKOM Centre, in the undulating grassland, there was a low-lying marsh to which one could pay useful visits in between sessions. Here, in addition to numerous passerines, plovers and water birds, one could see the occasional Lanner Falcon (Falco biarmicus), Black-shouldered Kites flying in every evening and, regularly at dusk, the Marsh Owl ( Asio capensis). Before and during the conference, which closed on 11 August with the adoption of 15 resolutions and a WWGBP members’ meeting, guided tours and individual excursions could be made to many parts of the Republic of South Africa. A number of participants also went on to attend the 22nd International Ornithological Conference, held at Durban from 18-22 August.


On these excursions it was depressingly evident to what a remnant status the formerly rich and abundant fauna of South Africa had been reduced. Those pristine eco-systems that survive are almost exclusively in national parks. Outside of these it is rare to encounter any wild animal larger than a small deer or fox, corresponding forcefully with other densely populated regions of the earth. True, in some localities there is still a wide variety of raptor species to be seen, but then only at a very low density of individuals, especially in the case of vultures. The Cape and Bearded Vulture (Gypaetus barbatus) populations in the Drakensberg mountains are at present still reasonably high in places, but are only maintained at this level by the establishment of artificial feeding places.


On arrival all participants received a booklet containing the abstracts of all oral and poster presentations. Since this has in the meantime gone out of print and experience has shown that only a certain proportion of presentations can be included in the published proceedings, we propose to include as a supplement to this and subsequent newsletters al selection of those abstracts which may be of interest to the many members who were unable to attend the conference.


The scientific programme and the papers, both oral and poster, in each session will be published in full in the forthcoming proceedings. In the following we give summaries of the most important issues covered, in the chronological order of the sessions.


Current Studies of African Raptors  (Conveners: A. Kemp & W. Tarboton)


A large number of the 22 presentations in this wide-ranging session were concerned with individual species (Cape Vulture, Madagascar Fish Eagle, Martial Eagle, Bat Hawk, Taita, Peregrine and Lanner Falcons, etc.), raptor communities in particular regions of the continent (Zimbabwe, West Africa, Kenya, etc.) and Madagascar, together with problems of their protection (measures to prevent birds of prey from drowning in cattle troughs and farm reservoirs). Fortunately attention was also paid to manmade and environmental influences on over-wintering species such as the Hobby (somewhat at risk during the spraying of crops) and Lesser Kestrel (very dependent on weather conditions). On the same lines as with closely-related specie in Europe and Asia, taxonomic problems and advances in solving the systematics of selected African raptors (Falco chiquera, Hieraeetus spilogaster, Circus ranivorus etc.) using conventional and moleculargenetic methods were outlined.


Biology and Conservation of the Vultures of the World  (Conveners: P. Mundy & G. Verdoorn)


One important element of this session was that it brought together working experts from many different parts of the world and so strengthened bonds and enhanced co-operation in vulture research in its many far-reaching aspects.

Valuable, too, was the debate provoked by the 14 oral and 6 poster presentations on both theorectical and current practical aspects of vulture conservation.

All Old and New World vultures were considered. In addition to individual species (particularly Cape, Egyptian and King Vultures), and the situation of regional vulture communities (South Africa and the African continent, Asia, Mongolia and North and Latin America), there was discussion in depth of the various threats these birds face, along with problems of their protection and management (the risk of poisoning, establishment of feeding places, re-introduction projects, etc.). Special attention was paid to new findings on the migratory behaviour of certain species (in particular the S.E. European Griffon).

Problems of vulture systematics were also addressed in depth in another session, to the solution of which the concept of a system of ecofunctional positioning was promoted. Based on this, functional equivalents between vulture communities in different regions could be objectively determined.


Falcons in Asia and the Middle East Falcon Research Group  (Conveners: N. Fox & V. Galushin)


This session, initiated by the Middle East Falcon Research Group, was above all concerned with the situation in recent years of the Saker Falcon in Asia (Kyrgyzstan, Kazakhstan, Mongolia) together with the data obtained from migration studies, presented in 9 oral and 2 poster papers. Beyond this were reports on the species’ status in European Russia and fresh developments in mid-central Europe. Other papers concerned particular species (Lugger and Peregrine Falcons), morphometric similarities (“Desert Falcons”) and problems of pesticide contamination.


Satellite Telemetry to study movements and habitat utilisation of raptors (Conveners: B.-U. Meyburg & M.R. Fuller)


In 5 papers, not only was the continually improving technique of satellite telemetry described, but also, outstandingly, the fresh insight it has provided into the migrations of Greater Spotted and Steppe Eagles and the Osprey. One Greater Spotted Eagle was tracked as far as Zambia, far south of its hitherto known wintering grounds. With Ospreys it could be confirmed that many of them fly over the Mediterranean at its widest point and then cross the Sahara not, as previously supposed, in a non-stop flight but in daily stages of similar length to those on the rest of their migration. Griffon Vultures from Israel roam not only to neighbouring countries (Jordan and Syria) but also as far as Turkey. For Peregrine Falcons from the Kola Peninsula in Russia, satellite tracking made it possible to locate the exact area in their European wintering ground where they acquired their pesticide residues.


Conservation Models for Raptors of the World  (Conveners: R. Watson & R. Hartley)


Oral papers were given by 13 authors, and a further two papers were presented as posters. Tom Cade presented a comprehensive review of progress in the translocation of raptors, providing the single most thorough source of knowledge to date on this raptor conservation tool. Lloyd Kiff presented a review of lessons learned from saving the Californian Condor, while others presented new ideas for raptor conservation, such as the community-based conservation of the Madagascar Fish Eagle and similar efforts for Black Eagles in the Matopos Hills of Zimbabwe. Public education was a recurring theme in many papers, including the use of falconry as a tool for conservation, particularly in Africa. Research and analytical tools for achieving conservation were presented by several authors, including a revealing analysis of management of the Wedge-tailed Eagle in forestry operations of Tasmania, and the demography of the Imperial Eagle in Kazakhstan. Together, these papers went far toward sharing the lessons learned from achieving conservation of birds of prey in a world where human demands for more fuel, food and other natural resources impact the survival of birds of prey in many complex ways.


Raptors in Urban Environment  (Conveners: D.M. Bird & G. Septon)


With the constant expansion of urban areas, so do an increasing number of birds of prey take advantage of it. Here they thrive, building their nests on tall buildings and masts and preying on synanthropic specie such as pigeons, starlings and sparrows. Since Peregrine Falcons are now breeding in over 60 cities in North America, to which 2 of the 7 oral presentations and 2 posters were devoted, this species is the most deeply studied of all city-dwelling raptors.


Circumstances in North America (Red-tailed Hawk Buteo jamaicensis nesting on buildings, urban birds of prey and owls in Tucson, Arizona, etc.) not unnaturally received the main consideration. But Palaearctic (Lesser Kestrel, Sparrow-Hawk) and supraregional similarities (e.g. Hobbies moving into town in Europe, Aplomado Falcons Falco femoralis doing likewise in South America) were also given close attention.


Understanding Distribution - the Whys and Wherefores of Geographical Ranges of Raptors (Conveners: N. Mooney & D. Pepler)


The distribution of raptors are basic to our understanding of their ecological requirements. Changes in distribution are nearly always indices of ecological changes, in modern times often as a result of man-made influences. 6 oral and 4 poster presentations were devoted at differing levels of the Golden Eagle in the Caucasus, Montagu’s Harrier in Spain and France, the Goshawk in Central Europe, the Lesser Kestrel in the steppes south of the Urals, and the distribution patterns of Australian raptors. These opened up a wide diversity of approaches to the subject. As migratory and nomadic species, Ospreys wintering in Costa Rica and Sea Eagles in Norway received special attention.


Shifting and fluctuating distribution ranges linked to various life forms were illustrated by comparisons between Montagu’s and Pallid Harriers. The sudden and abrupt drop in the numbers of Lesser Spotted Eagle passing through Israel on migration remains unclear; before that date the average was 104,000 but since then it has been only 76,000.


Predation and Feeding Ecology  (Conveners: I. Newton & R.A.G. Davies)


This session was concerned with the effects of predation by raptors on prey populations and the dependence of the former on food availability. In 7 presentations, including 2 review papers and 3 posters the following subject, among others, were addressed: vultures in northern Spain, Black Eagles and Hyrax in South Africa, the interrelation of birds of prey with domestic pigeons and also rabbits (in Australia) together with the impact of rabbit calicivirus disease, and the situation of the Burrowing Owl (Speotyto cunicularia) due to a lack of small mammals in northern South America. Other topics discussed included the effects of predation by Peregrine and Hen Harrier on the Red Grouse in Scotland and the results of brood manipulation in the Kestrel, to test Lack’s hypothesis that birds lay a clutch size that optimises the number of offspring they fledge.


Global Perspectives on the Status and Conservation of Migratory Raptors (Conveners: K. Bildstein & R. Yosef)


At least 192 of the 294 raptor species currently known in the world are wide-ranging, 69 (23%) of these under varying degrees of threat, and 19 (6%) of them exclusively migratory. In 8 oral and 1 poster presentations programmes were put forward for the monitoring and protection of such species which, due to their international links involving substantial expense, appear at present to be realisable only in specific instances. To date the responsible international agencies have scarcely begun to tackle this problem.


A few ongoing long-term projects, greatly enhanced by the adoption of telemetry techniques, have produced not only remarkable results but have also shown clearly the growing need for action. In North America declines in captures have indicated a decrease in numbers of sharp-shinned Hawks (Accipiter striatus) and American Kestrel (Falco sparverius), whereas in contract Cooper’s Hawk (Accipiter cooperi) has increased. The number of raptors migrating from North to South America through Veracruz (Mexico) is reckoned in millions, making this the world’s largest known concentration point, with for the seasons 1992-1996 a mean total of 3,296,808 birds of 19 species including 1,453,568 Broad-winged Hawks (Buteo platypterus), 510,943 Swainson’s Hawks (B. swainsonii ) and 1,204,263 Turkey Vultures (Cathares aura).


Compared with this, the number of raptors of various species migrating annually along the Black Sea Coast in Southern Bulgaria between 10 August and 30 October, averaging 65,020 birds seems extremely modest. These are predominantly Buzzards and Lesser Spotted Eagles. The number of migrating Steppe Eagles passing through Eilat in Israel has been very variable since the end of the 1970s, with an annual average of 16,023 (between 11,629 and 24,243). Alarm is caused by the fact that in 1996, over a period of 42 days only 2,228 could be counted and in 1997 only 9,283.


General Paper Session  (Convener: R.D. Chancellor)


This session comprised 8 oral presentations and 1 poster covering subjects which lay outside the scope of any of the other sessions yet were of considerable interest within the framework of raptor research. One study was on the complexity of nest-defence in Montagu’s Harrier, depending on whether breeding in isolation or colonially. Further studies on this species, and also the likewise semi-colonial nesting of Red Kite and Osprey, concerned the effectiveness of the male’s guarding the female prior to egg-laying. In relation to this, breeding Kestrels showed other dependencies - on already established polygamous mate relationships, copulation frequency, distances between nests and food availability.


The innocuous Barred Honey Buzzard (Pernis celebensis) benefits through “active mimicry” from its similarity to the militantly aggressive Spizaetus Hawk-eagle. In another study the suggestion was tested, with American Kestrels, that aversion conditioning to prey treated with a distasteful compound may have a practical application in reducing unwanted predation on some particular species. Another speaker had studied the manner in which different species used their feet when striking small mammal prey; this was variable (Kestrel and Buzzard used either foot indiscriminately), owls use both feet except for the Little Owl, which clearly prefers the right foot only.


The status of the still very little known Gurney’s Eagle (Aquila gurneyi) of the north Moluccan archipelago seems at present to be secure with 800-900 breeding pairs, but this could soon change with further widespread exploitation of the forest. In this connection there was a most interesting study on the effect of ever-extending afforestation with exotic trees on raptors, leading to recommendations to the South African timber industry on various aspects of raptor management.


Islands and Raptors    (Conveners: C. White & L.F. Oliveira)


This session was aimed at reviewing the diversity of raptors on islands and specific studies on given single taxa. One paper was general in nature, looking at the distribution and species numbers on islands using the Biological Species Concept, Phylogenetic Species Concept and Evolutionary Significant Units. At each level the number of “species” increases (nearly doubles) and islands become increasingly important at each level by containing proportionally more “species”. Islands therefore become increasingly important in the conservation of “species”.


The remaining papers dealt with single species and reviewed mainly status. A series of 3 papers dealt with the Cape Verde Islands but while the authors dealt with morphology and sexual dimorphism in Cape Verde kestrels, their status was not mentioned. The other 2 species, Osprey and Peregrine Falcon were deemed rare or decreasing in numbers, the former perhaps mainly because of human depredation. Decreases in numbers of Tasmanian Gray Goshawks and Christmas Island Hawk-owls were also reported and seemed to be related to habitat loss. These papers elicited some discussion on the conservation issue.


Then 2 papers dealt with dispersal and population movements, one on the Lanyu Scops Owl and one on the Seychelles Kestrel. The session was rounded out by data on the taxonomy and systematics of both the Reunion Marsh-Harrier and Eleonora’s Falcon, using both molecular DNA fingerprinting and extensive morphometric data. The question of species level was raised for the harrier. An added attraction was the final discussion on the use of molecular information in the enforcement of laws with raptors and while not specifically on islands it had generated discussion about its uses and abuses.


Impacts of electricity utility structures on raptors  (Conveners: C. van Rooyen & P. Nelson)


Contrary to what was expected, given the relative late scheduling in the programme, the paper session on raptor electrocutions was well attended and featured contributions from South Africa, the United States and Israel.  Richard Harness from Electrical Systems Consultants in Colorado gave two presentations. The first gave a review of raptor electrocutions and outages in the western United States over a period spanning 10 years, 1986 to 1996. Electrocutions are still a major cause of mortality in the USA, despite a widely held belief that the problem was largely solved a decade ago, with pole mounted transformers as probably the most lethal structure. His second paper focused on an emerging trend in the USA to use steel poles for electricity distribution purposes, and pointed out the increased risk of raptor electrocution associated with steel distribution structures generally. He also discussed alternative methods of construction aimed at moving away from steel constructions. Anne-Marie Sanches, representing APPLIC (the Avian Power Line Interaction Committee), gave a compelling overview of most important milestones achieved during thirty years of research and conservation action on the topic of raptor electrocutions in the United States, with particular emphasis on the work that APPLIC had been involved in since its formation.


Chris van Rooyen presented an overview of raptor electrocutions in South Africa, with particular focus on the activities of the Eskom-Endangered Wildlife Trust Strategic Partnership. He gave statistics that revealed that vultures, particularly the vulnerable Cape Griffon, are still the most often recorded electrocution victims. He also identified the most structures, and the infamous steel Kite-structure and pole mounted transformers came out top. Rudi Kruger from Eskom presented a paper co-authored with Chris van Rooyen on the methodology applied to assess the risk, that powerlines posed to raptors, systematically outlining the different factors taken into account in assessing the risks, and how the authors arrived at their conclusion. This paper is of particular value to electrical engineers designing and planning new lines.


Ofer Bahat described in his paper the measures that have been taken by the Israeli Electric Corporation, together with the Society for the Protection of Nature in Israel and the Israeli Nature Reserves and Parks Authority, to reduce the impacts of powerlines in Israel, particularly on the critically endangered Eurasian Griffon.


Biology of Owls with Emphasis on Vocalisation and Conservation  (Convener: Claus König)


For identification and intraspecific communication, owls, being nocturnal, rely more on vocalisations than on plumage patterns and colouration. Corresponding research has revealed the existence of over 200 species - many more than were formerly identified merely on the basis of plumage patterns. This in turn leads to new premises regarding plans and methods for their protection.


This approach was amplified in 5 oral and 4 poster presentations, and also one video film. Along with more faunistic concerns (owls of China, Eagle Owl in Portugal) and studies on individual species such as Tawny, Little and Pygmy Owls, rarities such as Otus irenae and O. insulares were also discussed in the light of the remarkable advances made of late in acoustic and molecular systematic differentiation. Geographical variations in calls within a species are in general not larger than individual.


According to the criteria of molecular systematics the Tytonidae and Strigidae are separate families. The genus Bubo should also embrace the at present separate genera Nyctea and Ketupa, whilst Surnia, Aegolius, Athene and Glaucidium from a monophyletic group.


Taxonomy, phylogeny, development in raptor DNA-studies and other theoretical aspects (Conveners: M. Wink & A. van Zyl)


The session consisted of 5 oral and 4 poster presentations directed towards DNA studies and taxonomic aspects of diurnal raptors. New methods of molecular biology have influenced nearly all fields in biology and opened a window to the evolutionary past of raptors, their phylogeography, population or pedigree structure. The amplification of marker genes, such as cytochrome b, by polymerase chain reaction (PCR) and the analysis of the aligned sequences by powerful tree building programmes has provided insight into the phylogenetic structure of the Falconiformes indicating that Falconidae, Cathartidae and Sagitaridae are distinct evolutionary units which are clearly separated from the “true” Accipitridae. Similarity in lifestyle and morphology in these groups are apparently derived characters which evolved convergently. Results were presented on the phylogeny of booted and sea eagles, vultures, Bateleur, buzzards and falcons.


Microsatellite PCR and DNA fingerprinting have become indispensable tools to elucidate the pairing systems of birds, potential hybridisations, population structure, heterozygosity or gene flow. One paper addressed forensic and conservation issues using DNA methods. A new approach used DNA fingerprinting to determine turnover and adult mortality of raptors by analysing the DNA profiles of the young birds in consecutive years.


PCR methods have recently been established to determine the gender of individual birds. This approach is especially helpful to study potential sex bias in populations or for the selection of birds which cannot be sexed by morphology alone in captive breeding programmes: results wee given for vultures and eagles.


Workshops and Round Table Discussions were held on 9.8.1998 on the following subjects: Co-operative Management of Raptor Electrocutions, convened by C. van Rooyen & P. Nelson; The Role of Satellite Telemetry and Internet in Education towards the 3rd Millennium, convened by Y. Leshem & M. Martell; and Legislation and Trade, convened by J. Parry-Jones & D. Newton. These three group discussions opened up possibilities for international co-operation, exchange of experience and co-ordination in the field of raptor research.


The closing session on 11.8.1998 began, by way of introduction, with an assessment of the results achieved by Resolution 15 of the IV World Conference in 1992, concerned with the protection of migrating birds of prey passing through Syria. This had led to a legal ban on hunting which, however, had induced a wider use of poison in the fight against predatory wild animals and thereby remained a continuing threat to large carrion-eating raptors (vultures, Steppe and Imperial Eagles).


Following on this report came the debate on and formulation of Resolutions from the present World Conference, the final versions of which are published below. On behalf of the WWGBP Council Robin Chancellor, Hon. Secretary and Treasurer, then reported on the Group’s activities, during which, at the request of the Chairman, he explained that, for the future operation of the WWGBP it was becoming necessary to find younger members prepared to take over the work and join the Newsletter editorial board and executive committee. In this connection several members (Gero Speer, Dr. Wolfgang Baumgart, Prof. Dr. Kai Graszynski) had given the Chairman active support in preparing the German language version of the Newsletter, but the English language version still remained predominantly the responsibility of Robin Chancellor and Bernd-U. Meyburg. Since that time Nick Mooney from Australia has generously offered to play a major part in preparing and editing the Newsletters.


To end the meeting the officers were re-elected for a further term nem. con. and Nick Mooney proposed Australia as the venue for the VI World Conference. There was also an invitation from Hungary for an international and, if the occasion arose, World Conference.




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