Changes in the Status of Birds of Prey in Europe by I
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Changes in the status of birds of prey in Europe By I. J. Ferguson-Lees (Plates 21-26) INTRODUCTION THIS PAPER SETS OUT to review, in the broadest terms, the present breeding status of diurnal birds of prey in Europe and the factors which have brought about increases or decreases during the last century; it •excludes the owls because too little is known about many of them. It is based on an extensive survey of the literature and forms part of a wider study concerned with status changes in all groups of European birds. Many generalisations can be made only after consulting a •considerable number of references and to cite the relevant ones in support of each point would make the whole unnecessarily tedious. For this reason, and because it is hoped eventually to publish the wider survey elsewhere with full references, sources of information have been omitted. They can, however, be supplied to those interes ted in particular aspects. The paper also includes information based on first-hand experience in Spain, France, Fenno-Scandia, Bulgaria and Rumania in recent years, as well as data gathered from correspondents in many parts of Europe. This material is being published now as a background against which the effect of toxic chemicals on birds of prey may be assessed. The plates have been selected to bring out some of the points made in the discussion. The species illustrated are chiefly ones which have not been published in British Birds during the last ten years and the reader is reminded that a considerable number of photographs of other birds of prey have appeared in that time—including Lammergeier, Bonelli's Eagle, Goshawk, Kite, Black Kite, Honey Buzzard, Osprey, Eleonora's Falcon and Lesser Kestrel.* In addition, photographs of Buzzard and Hen Harrier are being reproduced in our next issue. SUMMARY OF THE PRESENT SITUATION Excluding owls, thirteen (or just possibly fourteen) species of birds of prey breed in the British Isles, five or six of them being extremely rare and confined to one or two localities; another ten species have occurred as vagrants. In Europe as a whole, 39 species of diurnal birds of *The scientific names of the birds of prey can be found in the appendix on page 148; those of other species are given in the text. 140 STATUS OF BIRDS OF PREY IN EUROPE prey breed, or 37 if one excludes Pallas's Sea Eagle and the Tawny Eagle whose ranges only just touch the extreme south-east corner of European Russia and about whose status there is, in any case, con siderable doubt. Of these 37, two-thirds are resident and the remain der move south for the winter, chiefly to Africa. This total is made up of four vultures (Neophron, Gyps, Aegypius, Gypaetus), six eagles (Aquila, Hieraetus), three buzzards (Buteo), three round-winged hawks (Accipiter), three kites (Milvus, Ulanus), one sea-eagle (Haliaetus), one honey buzzard (Pernis), four harriers (Circus), one harrier-eagle (Circaetus), one osprey (Pandion) and ten falcons (Falco). Of the 37, 20 have decreased markedly this century, five more probably have, nine are just holding their own (or have offset decreases by increases elsewhere) and only three have really increased. The decreases include all the vultures, all the eagles except Booted, two of the kites, Marsh and Montagu's Harriers (except in the Baltic area and central Europe), the round-winged hawks and most of the large falcons. Holding their own are the buzzards, the Hen Harrier and the small falcons. Spreading are the Black Kite, the Pallid Harrier and the Red-footed Falcon. Only the Buzzard, Sparrowhawk, Goshawk, Peregrine and Kestrel are really widespread in almost all parts of Europe where the habitat is suitable, though the Golden Eagle is generally distributed, often in very small numbers, in mountainous regions. Seven other species have a fairly wide distribution on the Continent, however, without extending into the more northern parts and in some cases being scarce or absent in the extreme south or south-east. These are the Kite (common also in the south but absent from the extreme east), Black Kite, Honey Buzzard (fairly widespread also in Fenno-Scandia), Marsh Harrier (common also in the south), Montagu's Harrier, Short-toed Eagle and Hobby (everywhere except much of Britain and Scandinavia and the Mediterranean islands). The Rough-legged Buzzard, Gyr Falcon, Merlin and Hen Harrier are primarily birds of the extreme north, though the last extends to many areas in the northern half of the main mass of the Continent, from northern Spain and northern France eastwards. The Egyptian and Griffon Vultures and the Lesser Kestrel are essentially southern species, while the Black Vulture, Lammergeier and Imperial, Bonelli's and Booted Eagles are confined to the south-west and south-east. In the south-east alone are the Levant Sparrowhawk, Long-legged Buzzard, Lanner and Saker, while the Spotted and Lesser Spotted Eagles, Pallid Harrier and Red-footed Falcon are primarily found in the eastern third of the Continent. The White-tailed Eagle is now missing from the western third, while the Osprey is confined to the north and east and the extreme south (with a great gap in between). The Black-winged Kite is found only in 141 BRITISH BIRDS western Iberia and Eleonora's Falcon only in the Mediterranean islands. In general, birds of prey are more numerous in the south of Europe than in the north. Iberia and the Balkans have the greatest number of species and only in these areas, except at times of passage, are they still really numerous. This particularly applies to the comparatively undeveloped regions of southern Spain and Greece. INCREASES AND DECREASES The causes of the increases and decreases are very varied, but, with a few minor exceptions, are all brought about by man. Broadly speak ing, they may be divided under shooting and trapping, poisoning, modern hygiene, habitat destruction, adaptability, climate and inter specific competition, though very little is known about the effects of the last two of these. Shooting and trapping Guns and traps have long been used senselessly against any bird with a hooked bill, but certain groups have come in for more than their fair share and in the cases of some species this has been a major factor in their continued decline—especially the eagles, Red Kite, Marsh Harrier, Goshawk, Sparrowhawk, Osprey, Peregrine and Merlin. The Golden Eagle, for example, has been exterminated in many parts of Europe and is now successful only in the wilder mountains, especially parts of Spain and Greece and the Swiss and Austrian Alps, Locally within these areas it has increased, as it has done in Scotland this century: thus in Switzerland there are now 40-50 pairs where there were only 20-30 earlier in the century. Similarly, the White-tailed Eagle has been harried out of many parts of its European range just as it was driven out of Scotland in 1908. It appears now to have been exterminated in Corsica and Sardinia (the westernmost 'black' areas on the Field Guide maps, apart from Iceland). There are less than 50 pairs left in Sweden and only about 25 pairs in Finland; in the latter part of the 19th century there used to be as many as 5 o pairs in Denmark, but- it was exterminated there by 1912 and only odd pairs have tried to breed since. Its strongholds in Europe are now the coasts of Norway (where there are something over 200 pairs), northern Russia (though it is declining in the more populated parts) and some regions in the Balkans (in Rumania, for instance, it is now protected as a 'National Monument'). It is still shot in many areas, however, and the general picture is one of steady decline. Many other examples could be given. The Red Kite was formerly widespread throughout western Europe, but was gradually extermi- 142 STATUS OF BIRDS OF PREY IN EUROPE nated in most of Britain and, more recently, in Norway and Denmark {where, however, there has been a single recolonisation); and man's campaign against it because of real or imaginary depredations on chickens has now made it a local and not very numerous bird over most of the rest of its range. Marsh Harriers are still frequently shot, often largely because they are one of the easier birds of prey to kill and because they hunt in the same areas as wildfowlers. The Goshawk formerly bred in Britain (and may now do so again in one or two localities), but this, like the Sparrowhawk, has always been a primary target of the game preserver and it is now a scarce bird nearly every where throughout its wide range. The discontinuous breeding range of the Osprey (which used, for example, to nest in Denmark) and the absence or scarceness of the Peregrine on many suitable cliffs are further tributes to man's prowess with the gun. Poisoning Poisoning can be divided under two separate headings—direct and indirect. Only the large, carrion-eating eagles have suffered much from direct poisoning and, inevitably, this has again particularly affected the Golden and White-tailed. Fortunately, however, the practice of putting out poisoned carcases to kill eagles is not very widespread. What has had an indirect but much more serious effect in eastern Europe—especially Bulgaria, Rumania and possibly Russia— has been the custom of setting poisoned bait for Wolves {Cants lupus). All too often vultures or eagles find the bait first. This is considered to be the main reason for the extermination of the Lammergeier in the Carpathians in the mid-1930's (though it should be added that the Lammergeier is one of the first species of vulture to go when conditions are acting against the carrion feeders and it has now been driven out of the whole of Europe except for three areas of Spain, the southern Balkans and the larger Mediterranean islands).