Preventing Birds of Prey Problems at Transmission Lines in Western Europe
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j RaptorRes. 33 (1) :43-48 ¸ 1999 The Raptor ResearchFoundation, Inc. PREVENTING BIRDS OF PREY PROBLEMS AT TRANSMISSION LINES IN WESTERN EUROPE PATRICK BAYLE 15 rue Bravet, 13005 Marseille, France Among the 37 speciesof birds of prey (28 fal- (Real et al. 1996) and Spanish Imperial Eagles coniforms and 9 strigiforms) that breed or winter (Ferrer and Hiraldo 1990). regularlyin westernEurope, at least30 (24 falcon- Investigations in Germany, France and Spain iforms and 6 strigiforms) have been killed on pow- show that, among the 37 speciesof raptors that erlines,either through electrocutionsor, to a lesser breed or winter regularly in western Europe, at extent, through collisionswith electric wires. Mor- least 30 specieshave been victims of powerlines tality on medium voltagedistribution lines plays an (Table 1). Raptors most often found dead under important role in the global mortality of certain powerlines are common speciessuch as Common eagles, especiallyamong juveniles (e.g., Spanish Buzzards( Buteobuteo), Black Kites ( Milvus migrans) Imperial Eagle [Aquila (heliaca)adalbertz] in Spain and Eurasian Kestrels. and Bonelli's Eagle [Hieraaetusfasciatus] in Spain Medium voltage powerlines (1-60 kV) are re- and southern France) and is responsiblefor the sponsible for most of the raptor mortalities on general decline of these species.Powerlines also electriclines. In France,96.5% of 649 birdsof prey have an important impact on some common birds found dead under transmission lines were under of prey, both regionally (e.g., EurasianEagle Owl medium voltage powerlines (Striot and Rocamora [Bubobubo in the southern French Alps) and lo- 1992). The low impact of high or very high voltage cally (e.g., Eurasian Kestrel [Falcotinnunculus] in powerlines (60->150 kV) on raptors is illustrated different areas in France). Different devices have by studies of the avian mortality on portions of been developed to assure a better isolation be- such lines in the Netherlands (Heijnis 1980), Ger- tween electric wires and pylons and to prevent many (Hoerschelmann et al. 1988), France (Bayle birdsfrom perching on electricpoles, but the most and Iborra unpubl. data) and Italy which showthat efficient protectionis to bury the lines. Countries birds of prey representbetween only 0.1-0.4% of such the Netherlands (which have already all birds killed on theselines. In the French study achieved this aim), Belgium, Germany and the (Striot and Rocamora 1992), all birds of prey U.K. now intend to bury all their medium voltage found under high or very high voltagepowerlines lines. were killed by collision with transmissionlines. Since then an immature Bonelli's Eagle is known BIRDS OF PREY VS. POWERLINES IN WESTERN EUROPE to have died from electrocutionon a 63-kV power One of the major factorscausing declines in rap- structure near Marseillesin August 1992 (Cheylan tor populations is pollution, but forms of distur- and Bayle unpubl. data). Of the raptors killed on bance such as habitat loss and persecution have medium voltage powerlines,93.5% were electro- adverseeffects on raptors(Newton 1979, Gensboel cuted and 6.5% collided againstelectric wires. 1984). Accidental deaths that come to notice usu- In France and Spain, the role of powerlines in ally involve collisions of raptors with vehicles, the general mortality of raptors has been studied buildings and other structures (Newton 1979). recently in specieswith small populationssuch as One of the human causesof mortality,which has the Spanish Imperial Eagle (Ferrer and Hiraldo been overlooked in Europe, is the powerline web 1990), Golden Eagle (Aquila chrysaetos,Couloumy with which raptors collide or electrocute them- 1993), Bonelli's Eagle (Real et al. 1996) and Grif- selves.For certain species,collisions and electro- fon Vulture (Gypsfulvus, Terrasse et al. 1994). cutionson overheadwires form a major part of the Since this form of mortality affectsmainly juvenile total mortality and in extreme casesthey may have birds, it can have an important impact on the pop- contributed to raptor declines.This type of mor- ulation dynamicsof these speciesand be critical tality is a major threat for speciessuch as Bonelli's for their survival. Between 1974-88, 51.5% of 68 43 44 EXPANDEDABSTRACTS VOL. 33, NO. 1 Table 1. Raptor speciesaffected by mortality on electricpowerlines in three European countries(Germany, France and Spain). SPECIES D a F E Osprey ( Pandionhaliaetus) ..{-b Common Buzzard ( Buteo buteo) +++ Rough-leggedBuzzard ( Buteolagopus) + Honey Buzzard (Pernisapivorus) + + Black Kite ( Milvus migrans) + + Red Kite ( Milvus milvus) ++ + Short-toedEagle (Circaetusgallicus) + Bonelli's Eagle (Hieraaetusfasdatus) + Booted Eagle ( Hieraaetuspennatus) + Golden Eagle (Aquila chrysaetos) + SpanishImperial Eagle (Aquila ( heliaca)adalberti) + Bearded Vulture (Gypaetusbarbatus) European Black Vulture (Aegypiusmonachus) Griffon Vulture ( Gypsfulvus) Egyptian Vulture ( Neophronpercnopterus) European Sparrowhawk( Acdpiter nisus) Northern Goshawk( Acdpiter gentilis) +-4- Marsh Harrier (Circusaeruginosus) Hen Harrier (Circuscyaneus) Montagu's Harrier (Circuspygargus) + Peregrine Falcon (Fatcoperegrinus) + European Hobby (Fatcosubbuteo) + Merlin (Falco columbarius) + Eurasian Kestrel (Falco tinnunculus) +++ +++ Barn Owl ( Tytoalba) + ++ Eurasian Eagle Owl (Bubobubo) + ++ Long-earedOwl (Asiootus) + Short-eared Owl (Asioflammeus) + Little Owl (Athene noctua) + Tawny Owl (St*ix aluco) + + Total number dead under powerlines 567 686 1282 • D--Germany (Haas 1980), F--France (Striot and Rocamora 1992, Niebuhr pers. comm.), E--Spain (Haas 1980, Castanoand Guzman 1989, Mugica 1989, Negro and Manez 1989, Ferrer et al. 1991,Agrupacion Naturalista Esparvel 1993 and Segaraand Martos 1993). •' q- <5%, q-q- 5-10% and q-q- q- >10% of the total number of raptorsfound dead under powerlines. Spanish Imperial Eagles found dead in Dofiana alonia and 82.6% in southern France (Real et al. National Park (Spain) were electrocuted.After iso- 1996). In the latter area where the total breeding lation or burial of powerlinesin 1987,juvenile sur- population is estimatedto consistof only 28 pairs, vival increased from 17.6% in 1986-87 to 80.0% in among 20 ringed juveniles found dead between 1988-89 (Ferrer and Hiraldo 1990). In northeast- 1990-95, 17 were killed on powerlines(Cheylan et ern Spain (Alicant, Murcia and Catalonia) and al. 1996). All Bonelli's Eagle populationsin north- southern France (Languedoc-Roussillonand Prov- eastern Spain and southern France are declining ence) powerlineswere responsiblefor 44.8% of the and, in some areas (Alicant and Murcia), the known mortalities of Bonelli's Eagles between abrupt decrease in population size seemsto be a 1980-93 (N = 58). The situation varied greatly consequence of high adult mortality through di- from one region to anotherwith only 5.2% of the rect persecution. In other areas (Catalonia and birds found dead in Murcia dying on powerlines southern France) where adult mortality is lower, as opposedto 38.0% dying on powerlinesin Cat- the decline has been more moderate and has been MA•CH 1999 EXPANDED ABSTRACTS 45 Table 2. Percent of general avian mortality on electric powerlinesin "Important Bird Areas" (1BAs)in the Plain of Crau and its vicinity (Bouches-du-Rh6ne,southeastern France), 1988-93. TYPE OF BIRD A a B C raptors (Falconiformes/Strigiformes) 40.0 14.0 0.2 corvids (Corvidae) 45.0 10.3 0.5 gulls and terns (Laridae) 3.0 15.9 61.6 herons (Ardeidae) 0.0 43.0 0.6 White Stork (Ciconia ciconia) 6.0 0.0 0.0 Greater Flamingo (Phoenicopterus ruber) 0.0 3.7 14.1 other birds 6.0 13.1 23.0 Total (N) 100 107 865 aA--electrocutions on medium voltage(<60 kV) distributionlines in the Plain ofCrau (IBA PAC 03) (Kabouche1991, Bayleunpubl data). B--electrocutions and collisionson medium voltage distribution lines in the Vigueirat marshes (IBA PAC 08) (Hecker et al 1992, Lucchesi unpubl. data). C--collisions on very high voltage (>150 kV) distribution lines in the saltworksof Fos-sur-Mer(IBA PAC 15) (Bayleunpubl. data). mainly a consequenceof habitat destruction and tors vulnerable (Deschamps 1980, Haas 1980, Sfir- high preadult mortality due to electrocution(Real iot and Rocamora 1992, Ferrer et al. 1993). The et al. 1996). problem is magnified when these powerlines tra- Raptors other than eaglesand vultures are also verse important raptor areas such as territories affected by powerlinesbut it is difficult to assess with important raptor breeding populations (e.g., the severityof the mortality since it varies greatly near vulture colonies) or terrains which attract from one population and geographicalarea to an- large numbers of birds of prey (e.g., hunting other. For example, powerlineswere responsible grounds such as marshlandsor steppes). For ex- for 22.6% of identified casesof mortality of Eur- ample, significantraptor mortality on medium volt- asianEagle Owls in Sweden(Olsson 1979) and Fin- age lines has been recorded at Dofiana National land (Saurola 1979 in Mikkola 1983), 32.5% in Park in Spain (Haas 1980, Ferrer et al. 1991) and Germany (Wickl 1979), 54.7% in France (Bayle in southeasternFrance near the plain of Crau and 1992 and unpubl. data) and 16.3% in Spain (Her- its surroundings(marshes to the westand saltworks nandez 1989). In the southern Alps and Mediter- to the south). This area in France is a hunting ter- ranean area, the proportion of Eurasian Eagle ritory for Short-toed Eagles (Circaetusgallicus) in Owlskilled by powerlinesvaried from 45.5% in the the postnuptial period, a wintering area