Movements of British Raptors

Transcription

1 Bird Study ISSN: (Print) (Online) Journal homepage: Movements of British Raptors C. J. Mead To cite this article: C. J. Mead (1973) Movements of British Raptors, Bird Study, 20:4, , DOI: / To link to this article: Published online: 23 Jun Submit your article to this journal Article views: 321 Citing articles: 15 View citing articles Full Terms & Conditions of access and use can be found at

2 Movements of British Raptors by C. J. Mead The results of ringing over the last 60 years show that while the majority of British raptors migrate within the British Isles, some go to Europe and a few to Africa This analysis looks at British recoveries, both of locally bred and foreign birds, in the context of European movements as a whole. Besides providing information on migration routes and winter quarters, the ringing results emphasise that raptor conservation needs to be on an international scale, THIS ANALYSIS of the movements of British birds of prey as shown by ringing results takes note of all recoveries on the Ringing Office files of British ringed birds, and of birds ringed abroad and recovered in Great Britain.* The material is summarised in Table I. For some species recoveries of birds which did not fledge have been omitted, so that the totals of recoveries of British birds, in some cases, will be less than those given in the Annual Ringing Reports of the Scheme. Thomson (1958 a and b) analysed the 667 raptor recoveries then available: a total of 1,837 has now materialised from British ringing. An analysis of Kestrel recoveries has been published by Snow (1968), and a detailed investigation of Sparrowhawk records is being carried out by Dr I. Newton. For these two species only the recoveries of British birds abroad and of foreign birds in Great Britain and Ireland have been considered. A detailed analysis of E. Balfour's Hen Harrier work in Orkney is being prepared but, since records of birds ringed elsewhere in Britain might not be included, internal British recoveries have been considered in the present investigation. Maps of the recoveries of each species are given (Figures 1-16), apart from the Golden Eagle and the single Rough-legged Buzzard (detailed in the text), all other foreign recoveries have been plotted whether to or from the.british Isles. These records, with a review of the information readily available from other west European ringing sources, are discussed under separate species headings. Particularly useful sources were Nordstrom (1963), Bemis (1966) and von Blotzheim (1971). In most instances the annual reports of the European ringing schemes have not been searched for individual recoveries. Also included is a resume of migration information from other sources to allow the British data to be put into context. The information given in Vaurie (1965), Brown and Amadon (1968) and Moreau (1972) proved most useful. *The final updating includes recovery batch coded

3 BIRD STUDY TABLE I. NUMBERS OF RAPTORS RINGED AND RECOVERED INVOLVING THE BRITISH ISLES. Number Recoveries Ringed in Within British Abroad to British Isles British Isles to British Species to Isles Abroad Isles Total Golden Eagle Buzzard Rough-legged Buzzard 0* Sparrowhawk Red Kite Marsh Harrier Hen Harrier Montagu's Harrier Osprey Hobby Peregrine Merlin Kestrel Totals *The only Rough-legged Buzzard ringed in Britain was a transported bird found exhausted on a ship. It was later recovered near to the place of release. Golden Eagle Aquila chrysaetos All nine recoveries of Scottish birds were of nestlings (=pulli) recovered between their first September and July of their second year. The most distant, in the subsequent May, was almost 100 km. from its place of ringing. All but one were more than 25 km. from their natal eyries, which demonstrates that immature Scottish eagles almost invariably move away from their parents' territories. Elsewhere in western Europe many of the southern birds are effectively sedentary, although often undertaking an altitudinal migration to lower areas for the winter. Farther north the tendency towards a southerly or southwesterly movement becomes more marked, with some young Finnish birds recovered 1,500 km. or even 2,000 km. from their eyries during the winter. As with other species migrating mainly by soaring flight eagles are loath to cross wide bodies of water, since these do not produce the necessary thermals. 260

4 MOVEMENTS OF RAPTORS Buzzard Buteo buteo Figure 1 gives the ten recoveries of British birds showing movements of more than 100 km. including one in the province of Aisne, northeast France. There are none in Britain of birds ringed abroad. All those plotted took place before the May immediately after the birds were ringed as pulli. Table II shows the first-winter recoveries from August to March from TABLE II. BUZZARD RECOVERIES FROM AUGUST TO MARCH (RINGED AS PULE. Distance moved Area of origin Under 50 km. Over 50 km. Total Highland Scotland N. England and Dumfries S. England, Wales and Shropshire Totals three different areas of Great Britain, and indicates that there is little difference in the numbers moving from these areas. Many recoveries of German Buzzards have been published in full by Zink (1959) and Mebs (1965), so that a detailed comparison of German and British results is possible. Table IIIA shows first-year and older birds from both Germany and Britain found at the same season. There is no evidence that younger birds move substantially more than older ones, although it is obvious that German birds are more mobile than British. This might well be because of the restricted range of the Buzzard in Britain. The two British records of movements over 250 km. were of 1962 nestlings from the New Forest (Hampshire) reported during September of that year. Table IIIB shows the recoveries from April to July split in the same way. This demonstrates, for both Britain and Germany, that breeding season recoveries of older birds are closer to their natal sites than those of first-summer birds. Since six of the nine second-summer records of German birds were more than 50 km. from their ringing sites they might best be considered with firstsummer birds as non-breeders. The German and British data refer to the nominate race Buteo b. buteo which is distributed east to about longitude 20 E. in Sweden and to 30 E. north of the Caspian Sea. There is an area of overlap with the eastern race Buteo b. vulpinus, but the migration patterns of the two are very different. Swedish, Finnish, German and Polish buteo generally move south and southwest during the winter to France, with a few in Spain and, 261

5 BIRD STUDY possibly, Corsica and the northern part of Italy. The maximum movements are in the region of 2,000 km. and many birds from the southern parts of the range hardly move at all. The different areas of origin of Figure 1. COMMON BUZZARD. All recoveries over 100 km. All 1st-year. None ringed abroad have been found in Britain. 262

6 MOVEMENTS OF RAPTORS wintering Buzzards in France are well shown in von Blotzheim (1971), using the results of ringing in Switzerland, Germany and southern Sweden. On the other hand, the majority of vulpinus move south or east of south in the autumn to Asia Minor, and as they are soaring migrants they avoid the direct crossing of the Mediterranean. They spend the winter in Africa, mostly in central eastern areas but also south to Cape Province. A very few, from the western part of the range, migrate southwest through France and Spain and into northwest Africa across the Straits of Gibraltar. The migratory divide is clearly shown by Finnish recoveries published by Nordstrom (1963). It is possibly those individuals migrating this way that have been recorded in the Gabon. Brown and Amadon (1968) consider that buteo never reaches North Africa, although Vaurie (1965) thinks that small numbers of this race are stragglers there. Nine Buzzards ringed as nestlings are reported by Bernis (1966) from Iberia. Three were from Germany, one from Norway, four from Sweden and one from Latvia: the last, and one or two of the Swedish birds, were probably vulpinus. TABLE HIA. BRITISH AND GERMAN BUZZARDS, COMPARING AGE WITH DISTANCE MOVED (PULLI RECOVERED FROM AUGUST TO MARCH). Distance moved Origin and Age Under 50 km km. Over 250 km. Total British first year British older tgerman first year 127* tgerman older tdata from Zink (1959) and Mebs (1965). *May include a few recovered during their first July. TABLE IIIB. BRITISH AND GERMAN BUZZARDS, COMPARING AGE WITH DISTANCE MOVED (PULLI RECOVERED FROM APRIL TO JULY). Distance moved Origin and Age Under 50 km km. Over 250 km. Total British first year British older tgerman first year t *German older tdata from Zink (1959) and Mebs (1965). *Six of nine second-year recoveries were more than 50 km. Rough-legged Buzzard Buteo lagopus The only recovery (not mapped) is of a nestling ringed in Jaintland, central Sweden, during 1926 and recovered the following winter at Lochaber in southern Inverness, west-south-west of the ringing site. In most years relatively few Rough-legged Buzzards are recorded in the British Isles and these are usually in eastern areas. The results of Fenno- Scandian ringing given in Nordstrom (1963) and von Blotzheim (1971) show the normal southward movement of this species during the winter, 263

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8 MOVEMENTS OF RAPTORS with recoveries almost reaching the Caspian and Mediterranean by March. Rather few records show much westward movement and, since this is a soaring migrant, the North Sea must present a formidable barrier to west or southwest migration of this northern species. Sparrowhawk Accipiter nisus Figures 2 and 3 show all the foreign recoveries of Sparrowhawks ringed in Britain and Ireland, and all recoveries in Britain of birds from elsewhere. As yet no undoubtedly native British Sparrowhawk has been found abroad. Recoveries within Britain of British birds have not been analysed (see introduction). Most of the records refer to sexed birds and Figure 2 shows only the 19 females. Figure 3 shows the seven males and four recoveries of unsexed birds. On the basis of these rather sparse data it seems possible that female Sparrowhawks wintering in Britain from abroad are to be found slightly farther north than males. The majority involve birds marked on passage in Britain or abroad, but the two recoveries during the breeding season and the three of nestlings ringed abroad show that some British wintering and passage birds come from southern Norway and central Sweden. It is interesting that three of the seven passage and wintering places abroad associated with recoveries of males should be farther south than any of the 16 female sites. Belopolski, in a paper on European Sparrowhawk migration reviewed in Bird Banding, 44: 67, shows in an analysis of 71 recoveries of birds ringed at Courish Spit on the Baltic coast that males moved farther southwest than females (average distance 1,328 km., compared with 927 km.). Thus, although the direction of movement is the same, the winter ranges of the sexes do not coincide. This reinforces the tentative findings from British ringing records and suggest a winter manifestation of Bergmann's rule between the larger female and smaller male within the species. Schelde (1960) has shown that west Danish Sparrowhawks are less migratory than eastern ones: five out of 39 and 20 out of 41 October to February recoveries from west and east Denmark respectively were from abroad. It is not surprising that the British population, immediately to the west of Denmark, should be even more sedentary. Recovery maps by Schelde (1960), by Nordstrom (1963), Perdeck and Speek (1967) and von Blotzheim (1971) show the southwesterly movement during the autumn of locallybred Sparrowhawks to winter as follows: Danish birds in France and the Low Countries, Dutch birds in north and west France, Finnish birds in south Sweden, Denmark, north Germany, Belgium and France, Central German birds in central and southeast France. 265

9 BIRD STUDY Migrants caught in the Netherlands originated in Scandinavia. Although Finnish birds are clustered around the Netherlands very few are actually ringed or recovered there. Schelde's analysis of the Danish recoveries also shows that first- and second-year birds have a stronger tendency to move than older birds. The 39 recoveries of sexed Danish birds were very evenly distributed between Denmark and abroad. The Baltic (and presumably North Sea) does not appear to be an obstacle for this species which, although it will soar when conditions are favourable, regularly uses flapping flight on migration (Rudebeck 1950). Wintering migrant Sparrowhawks regularly reach the Mediterranean and there is a German recovery in Sicily. Two German birds have also been found in northwest Morocco and some birds regularly winter south to the Sahara. A very few cross the Sahara, sometimes even reaching the Equator (Brown and Amadon 1968). In general, the more northerly and easterly breeding populations move farther during the winter than westerly and southerly ones. A very small minority of Finnish Sparrowhawks winter in Finland (Nordstrom 1963). Red Kite Mi/vus mi/vus Figure 4 shows the three movements of Welsh nestlings (the fourth was recovered locally) and the single Schleswig-Holstein bird recently reported from Wales. All four Welsh birds were in their first year, the one in Kent only two months after ringing. The three distant records seem to indicate a regular southeasterly dispersal of the progeny of the very restricted Welsh population, and recruitment of native-bred birds to this population may well depend as much on Kite conservation in southeast England as in mid- Wales: systematic ringing did not start until 1968 so that this important information has only recently become available. It seems unlikely that any of the Welsh population habitually leaves Britain. The finding, within the area of the Welsh breeding population, of a Kite ringed as a nestling on the northwestern edge of the species' range in central Europe, was most unexpected. Although it was in its first summer, and so would not have been breeding, it suggests that there is some chance of new genetic material reaching this relict population naturally rather than by the artificial introduction of birds or eggs from elsewhere which has been attempted in the past. On the Continent the Red Kite is migratory, often reaching the Mediter- 266

10 MOVEMENTS OF RAPTORS FROM WALES TO WALES Figure 4. RED K11E. All recoveries demonstrating movement involving Britain are plotted. All birds were ringed as pulli and recovered during their first year Welsh ringed birds outside the breeding season and the German one in its first summer. ranean islands and sometimes northwest Africa (Brown and Amadon 1968). A map in von Blotzheim (1971) shows a very restricted corridor of recoveries directly southwest from two German ringing sites, while Goethe and Kuhk (1951) mention recoveries southwards to Italy and Sicily of birds ringed elsewhere in Germany. The 52 Iberian records mapped by Bemis (1966) came from Switzerland north to southern Sweden: all but three were in inland provinces of Spain, ten being in the central province of Toledo. Marsh Harrier Circus aeruginosus Figure 5 shows the three foreign recoveries of British Marsh Harriers and the two British recoveries of birds ringed abroad. The most distant internal one was about 250 km. southwest, within two months of ringing as a nestling, and the next most distant was a first-summer bird 100 km. west in June. Eight of the other ten were found during the August, September and October of their first autumn. Another was about 10 km. from its nest-site in its first December, and the last, in July of its second summer, had moved about 45 km. within East Anglia. 267

11 From U.K. From abroad 1st year C 2nd year 0 3rd year Figure 5. MARSH HARRIER. All recoveries to or from abroad. The farthest movement within Great Britain was ca. 110 km. All were recovered during spring except the bird in France which was killed in August. Ringing sites are marked by stars. 268

12 MOVEMENTS OF RAPTORS Recovery maps or analyses are available from the Netherlands (Perdeck and Speck 1965), Germany (Goethe and Kuhk 1951, Missbach 1969), Finland (Hilden and Kalinainen 1966) and some other areas (Haas 1954). From most countries the direction of migration is south or southwest, but some individuals from most populations remain close to their natal areas during the winter. This tendency decreases the farther north and east the population breeds. The main wintering area is southern Europe, with substantial numbers recovered in central and northern France and fewer in North Africa. There are many sight records from tropical Africa, and most of those from the west are from the Chad or Niger flood areas with a few on the Guinea coast (Bannerman 1956). Apart from the British bird in Mauretania the only trans-saharan records are from Finland in the Cameroons (one out of 25 foreign recoveries) and from the Netherlands in Senegal (one out of 50 abroad). Although six out of more than 200 German birds are from Morocco and Algeria none penetrated farther south. Bernis (1966) gives 24 recoveries in Iberia, from Switzerland northwards to south Sweden; they are mostly during the last three months of the year and are mainly from the provinces of Tarragona and Valencia, which have extensive marshy areas. Although quite capable of making long crossings of arid country, or seas, whilst on migration, wintering Marsh Harriers invariably associate with wetlands. Hen Harrier Circus cyaneus /711 \,\\ \S Figures 6 and 7 include all movements within Britain and Ireland greater than 100 km. as well as all recoveries to or from abroad. Of the 35 records 27 originated from the Orkney study (see introduction). When Thomson published his analysis in 1958 there was only one distant movement of a bird not originating in Orkney. The British evidence shows a southerly movement during the winter with exceptional birds travelling 500 or even 1,000 km. Four distant breeding season recoveries, especially the three of birds older than the first year, may well indicate the colonisation of fresh areas by the vigorous Orkney population. First-summer and sixth-summer birds were actually found on the Continent. Little information is readily available from continental ringing although the Finnish example in Kent shows that northern birds will move long distances. The Dutch bird in Lancashire had been marked as a nestling but the other, which travelled from Antwerp to Norfolk, was ringed as an adult male in November. Goethe and Kuhk (1951) list German recoveries 269

13 270

14 MOVEMENTS OF RAPTORS and show that a few may remain in Germany and the Netherlands, but that most winter in France and Italy. Berths (1966) records two north German birds, in northeast Spain and on the north Portugese coast. Most of the Hen Harriers wintering on the southeast shores of the North Sea originate in Norway and Sweden. The normal southern limit of winter birds is the Mediterranean, but there are records from northwest Africa (Vaurie 1965). Montagu's Harrier Circus pygargus Figure 8 shows all recoveries of British birds over 100 km. from ringing sites and the single foreign bird, reared at Texel (Netherlands), found in Britain. (Bannerman (1956) incorrectly gives two.) None of the birds plotted on the map was ringed within the last ten years and the majority (14 out of 22) were ringed more than 20 years ago. The distribution of localities within Great Britain cannot be taken to reflect the current breeding distribution of this scarce species. The map shows the movement out of Great Britain in the autumn; also that there are six breeding season recoveries of birds some distance from their natal areas hardly surprising with an opportunistic breeder like this harrier. All the solid symbols abroad represent recoveries between 19 August and 4 October, apart from the Portuguese bird reported as 'October'; thus the map gives no indication of the species' winter quarters. Since the great majority of these were shot there could be no clearer indication of the damage that can be done to one country's potential breeding population by indiscriminate hunting elsewhere. It is a source of great satisfaction that all raptors and owls have been protected by law in France since 24 January 1972, perhaps too late to save this species in Britain. TABLE IV. MONTAGU'S HARRIERS BY AGE AT RECOVERY. Juveniles 1st-summer 2nd-summer Older Recovered Aug. Oct. May Aug. May Sept. May & Aug. Total In Great Britain Abroad Totals Table IV shows that only three of the 33 recoveries of British birds were during their first summer, although nine second-summer birds were reported. This may well indicate that many first-summer birds remain in winter quarters rather than return to the breeding areas. Little information is available from elsewhere. Gentian recoveries in Goethe and Kuhk (1951) are from France (five), with one each from 271

15 BIRD STUDY Figure 8. MONTAGU'S HARRIER. All recoveries to or from abroad or over 100 km. within Britain. Ringing sites are marked by stars. 272

16 MOVEMENTS OF RAPTORS Belgium, Italy and Spain. A further Spanish recovery of a German bird is mentioned by Bemis (1966), together with two from the Netherlands; all were ringed as pulli and found in September or October. Although a few are thought to winter in southern Europe and North Africa the vast majority cross the Sahara and go as far south as the eastern part of Cape Province. The only trans-saharan recoveries discovered were from central Europe to Chad and Nigeria. Moreau (1972) maps the West African winter distribution as between the Sahara and about latitude 8 N. i.e. not reaching the Guinea coast. The first autumn migrants reach Senegal as early as the end of September (von Blotzheim 1971) and, whilst it is accepted that there are probably many fewer Montagu's Harriers in West than East Africa, it seems possible that all the western European birds winter in West Africa. Osprey Pandion haliatus Figure 9 shows the six foreign returns from the ringing of nestling Ospreys in Scotland. Another has been reported from Scotland 200 km. west of the natal area during July of its second summer. As with the Montagu's Harrier, the growth of the British population is put at risk by the prevalence of hunting abroad. Figure 10 shows the nine Swedish nestlings recorded with full details from Britain: only one was reported as shot. Other ringed Ospreys, including breeding birds in Scotland, have been observed but it has not been possible to uniquely identify them although, by reason of ring design and partly deciphered numbers, some sightings are known to refer to Swedish birds. The six recoveries shown in Figure 9 were, from north to south, ca. 22 December, 31 August, ca. 7 November, 4 October, ca. 6 December and 21 January. Thus the most southerly and most northerly records were apparently of wintering firstyear birds. Eight of the nine Swedish birds in Britain were recovered within 28 months of fledging : the exception was the one from the North Sea oil rig which was over 12 years old. A good deal of ringing has taken place abroad and OsterlOf (1951) has published an analysis of Swedish results, while Nordstrom (1963) and von Blotzheim (1971) have provided recovery maps. Swedish birds travel between south and southwest with some first-year birds crossing the Mediterranean via Italy, although many go through Spain. Few older birds are taken in the Mediterranean region and they may overfly it between Italy and Spain. Ospreys are strong fliers, as is demonstrated by 273

17 274

18 MOVEMENTS OF RAPTORS the Swedish birds in Britain, and would certainly be capable of crossing the Mediterranean, and subsequently the Sahara, by direct flight rather than seeking easier ways round. Twenty-five of the 33 recoveries in Iberia mapped by Bernis (1966) were from Sweden, all but four being from the southeastern half of Spain. Finnish Ospreys travel within 15 of due south through Europe, and only three of 72 recoveries were farther west than longitude 10 E. However, the majority of the African recoveries are from the Gulf of Guinea, demonstrating a distinctly western shift in Africa. Single recoveries on the Black Sea, eastern shore of the Mediterranean, and at the south end of the Red Sea show that a minority of Finnish Ospreys take a definite southeasterly route. Two British recoveries south of the Sahara, in Mauretania, were farther northwest than any of 57 trans- Saharan recoveries plotted by von Blotzheim; but too much should not be made of this since both were from the same brood. The other southern record was also on the northwest edge of the wintering range. Ospreys winter right into the south of Africa but, as specialised fish-catchers, they are invariably associated with areas of water. Some non-breeding birds remain in winter quarters as late as May. Hobby Falco subbuteo Figure 11 shows the two foreign recoveries of British nestlings and the Finnish one found during September in Norfolk. The French recovery was in October and the Portuguese one in September. The only internal movement of more than 10 km. was of a first-summer bird found in August 160 km. north of its Wiltshire nest-site. All falcons are basically flapping-flight migrants, although they will take advantage of good soaring conditions, so the sea-crossings made by the Finnish bird are not surprising. Almost all Hobbies winter south of the equator and it is thought that their migration across the Mediterranean and Sahara is on a broad front (Brown and Amadon 1968). None from European ringing has yet been found in the African winter quarters although a very few winter recoveries have been made in Europe. It seems likely that these were injured birds since very few Hobbies are seen in Europe by bird-watchers during the winter. Bemis (1966) reports two September recoveries from northeast Spain, a Dutch nestling and a juvenile from North Germany. Heidemann (1935) and Goethe and Kuhk (1952) report five other distant German birds, three in Italy and two in France, all having travelled between south and southwest. One in each country was during April and the rest were from mid-september to early October. 275

19 BIRD STUDY From abroad All are first autumn Figure 11. HOBBY. All recoveries to or from abroad. Peregrine Falco peregrinus Figure 12 shows the only three movements of British birds of over 250 km. and the eight Scandinavian birds reported in England. Only a few additional recoveries have come to hand since a previous analysis (Mead 1969). Table V shows that only seven of the remaining 23 British Peregrines had moved over 100 km. However, on the sparse data available, it seems that both old and young British birds are equally likely to be recovered away from their natal areas. Ratcliffe (1972) knows of no increase in the breeding areas during the spring corresponding with the disappearance of wintering birds from lowland, non-breeding, areas. It is possible that dispersal during the first autumn serves broadly to determine 276

20 MOVEMENTS OF RAPTORS the area where the young birds will eventually settle to breed. The Norwegian and Swedish recoveries in Britain fit well into the pattern of a general southwesterly movement during the autumn shown by ringing on the Continent and it is probably these which are responsible for a majority of the lowland winter sightings. Figure 12. PEREGRINE. All recoveries from abroad and the three over 250 km. within Britain. No British ringed Peregrine has yet been reported from abroad. Ringing sites are marked by stars. As might be expected, the more northerly birds move farthest and there is an autumn find of a Finnish bird in the south of Spain. However, the majority of winter recoveries of Finnish birds are in central and western France (Nordstrom 1963). The German data published by Heidemann 277

21 BIRD STUDY From ICELAND Origin: op Icelandic pulli Fair Isle passage 00 British pulli Age: ego First winter El D Older Unknown Figure 13, MERLIN. All British recoveries of more than 200 km. and Icelandic ringed birds in Britain. No other Merlins ringed abroad have been recorded in the British Isles. Ringing sites in Britain are marked by stars. 278

22 MOVEMENTS OF RAPTORS TABLE V. PEREGRINES BY AGE AT RECOVERY. Recovered Juvenile! 1stwinter up to Feb. Mar.-Feb. Mar. onwards Total 2nd-year Older Under 100 km Over 1130 km Totals _ (1935) and Goethe and Kuhk (1952) include 30 winter recoveries (November to February) of which nine were still in Germany, eight in France, five in Belgium, four in Poland and one each in Portugal, Spain, Switzerland and Czechoslovakia. Additionally Bernis (1966) gives a further Finnish and three Swedish Peregrines found in Iberia, all seven between October and February. Although none has been recovered in Africa, specimens of European Peregrines have been taken in North Africa and some probably cross the Sahara. The situation in Africa is confused by the variety of races to be met with in the tropics, but Brown and Amadon (1968) think that European Peregrines may penetrate as far south as the Equator and quote a record of the Russian race F. p. calidus from Natal. Merlin Falco columbarius Figure 13 shows the recovery sites in Britain and Ireland of Icelandic ringed Merlins and all foreign recoveries, together with British ringed pulli and passage Merlins ringed on Fair Isle and recovered at a distance of 200 km, or more. The Icelandic ringed birds were all found within about 100 km. of a north- or west-facing coast. However, some of the passage birds trapped at Fair Isle showed the characters of the Icelandic race F. c. subaesalon, and three have been recovered. A bird 160 km. south in Caithness within a month of ringing does not appear on the map, but the others are the bird of unknown age in Perthshire, and the more southerly of the two in Belgium. The other Fair Isle passage birds may have originated in the Faeroe or Shetland Islands, or in Scandinavia, or they might be unidentified Icelandic individuals. TABLE VI. MERLINS (OCTOBER TO MARCH) BY AGE AT RECOVERY. Recovered First winter Older Total Under 100 km km Over 250 km Totals

23 BIRD STUDY British nestlings show a fairly steady southwards trend although it is obvious, from the data in Table VI, that most stay close to their natal territories. This table also shows that young birds are much more likely to move away for the winter than older ones. Twelve of the 16 breeding season recoveries of British nestlings were within 50 km. of the ringing site. The other four were of two second-summer birds 51 km. southwest and 180 km. south, a ttird-summer bird 120 km. north and a fourthsummer bird 150 km. north-northwest. These indicate good genetic mixing within the British population. On the Continent Merlins winter south to the Mediterranean, with a few reaching the northwest coast of Africa. Many only move as far as France, the Low Countries or Germany and some stay in southern Sweden. The only movements of Merlins ringed as nestlings mentioned by Berths (1966) were from southern Norway to Valencia, and three Swedish birds (one from the south and two from the far north) which went to northern Spain (provinces of Navarra, Logrono and Burgos). Kestrel Falco tinnunculus Three maps of Kestrel recoveries have been plotted. Figure 14 shows all those in Britain and Ireland of birds ringed abroad. Figure 15 shows recoveries abroad of fully-grown Kestrels ringed in Britain between August and December; also the six recoveries abroad, during the breeding season, of British pulli. Figure 16 shows the recoveries abroad, outside the breeding season, of British nestlings. Snow (1968) has already analysed the British recoveries. Figure 14 shows a generally easterly distribution of foreign Kestrels in the British Isles, although there are two in western Ireland. One first-summer bird from south Sweden (in Yorkshire) and two Belgian migrants (in Yorkshire and Kent) were found in Britain during the breeding season. Of those ringed during the breeding season eight originated on the continental shore of the North Sea, and seven in the northern quarter of the Baltic. The bird from Silesia (not 'Siberia' as stated by Bannerman 1956) is very puzzling; since passage birds ringed at Cap Bon in Tunisia have been recovered in this area. Recoveries of birds ringed as fully-grown (Figure 15) show that the five from Scotland were probably Scandinavian migrants which had crossed the North Sea; whereas the birds from English stations may well be native (compare their distribution with that shown in Figure 16). The six nestlings found abroad during May and June include the southernmost and northernmost recoveries of British pulli. The Moroccan one, during May 280

24 MOVEMENTS OF RAPTORS of its second summer, is most surprising, although Brown and Amadon (1968) state that some migrant Kestrels linger in the tropics as late as 10 May in some years. The Norwegian one, on 11 June, a third-year bird, probably represents a long-distance shift of breeding area, as may also the other older recovery in France during June of its third summer. Figure 16 distinguishes between birds ringed as pulli within, north of, and south of, the North of England area (coded 05) of the internationally accepted Euring recovery code: this is the Isle of Man and all English counties from Lancashire and Yorkshire north to the Scottish border. Unfortunately, the boundaries differ from those used by Snow when he showed that Scottish and North English birds were more migratory than Midlands and south English ones. He used the recoveries within Britain and Ireland as well as those abroad, but the latter then amounted to 38 and a further 23 have since been reported. His results are borne out by analysis of the foreign recoveries of British ringed nestlings about latitude Ringing Year of recovery month ? May-Jul Sep &Oct o 0 4) Recovered during June Figure 14. KESTREL. All recoveries of foreign ringed birds within Britain. Stars mark the recovery sites. Solid symbols are of birds ringed in the breeding season (all but the old Finland and the Belgian bird as pulli). Open symbols are birds ringed on passage from 30 September to 27 October. 281

25 a' 0, SAFI (MOROCCO) Year of recovery Ringed ? AS PULLI AS F-G 0 0 <> AUG-DEC RECOVERED MAY & JUNE Figure 15. KESTREL. Recoveries abroad during the breeding season (British ringed pulli) and of autumn and winter ringed birds from Britain (all times of the year). All birds in the last category were ringed between 11 August and 28 October save the Hampshire one (1 December). Ringing sites are marked by stars. TABLE VII. RECOVERIES ABROAD OF BRITISH RINGED KESTREL PULLI (NORTH AND SOUTH OF LATITUDE 49 N.). Age at recovery 1st-year 2nd-ygar Older Total Ringed in : N. S. N. S. N. S. N. S. Scotland N. England Wales and rest of England Totals

26 MOVEMENTS OF RAPTORS 0 0 R I NGED YE1AR FOU N D IN: q SCOTLAND 0 N. ENGLAND (shaded area) WALES+ rest of ENGLAND 00 CI Figure 16. KESTREL. Recoveries abroad, outside the breeding season, of British ringed pulli. None of these was ringed in Ireland. 283

27 BIRD STUDY 49 N. (passing just north of Paris) given in Table VII. This Table also shows, as did Snow, that young birds are more migratory than older ones; indeed, ten out of 15 older birds, asopposed to 13 out of 46 first-year birds, were recovered within 250 km. of the Straits of Dover. Only a minority of the British population does winter abroad. The analysis of Swiss recoveries by Schifferli (1965) shows not only the expected southwesterly movement of migrants out of Switzerland into Spain and North Africa (four birds), with single birds in Liberia and Madeira, but also an unexpected post-fledging dispersal of juveniles in late summer and autumn to the north and west. Ten involved movements of over 200 km. and some almost reached 400 km. Nordstrom (1963) mapped the Finnish results, which show winter movements between south and southwest to Italy and France (31 out of 62 winter recoveries), with six in Algeria and Tunisia. The 51 in Iberia plotted by Berths (1966) are mainly in northeastern and southern Spain. Apart from fully-grown birds from Belgium (three) and Denmark (one) they were all ringed as nestlings as follows: Britain four, Netherlands six, Switzerland 14, Germany nine, Sweden nine and Finland five. Kestrels will cross the Sahara and, apart from the Liberian bird already mentioned, a German bird has been found in Nigeria and a Czech bird in Ghana (Moreau 1972). The wintering range in West Africa reaches the north coast of the Gulf of Guinea and extends even farther south in East Africa. 284

28 MOVEMENTS OF RAPTORS ACKNOWLEDGEMENTS I would like to thank Leslie Brown for stimulating this investigation and the Ringing and Migration Committee for permission to use the files of British recoveries; also Mrs. A. Causer for typing the manuscript. Kenneth Williamson's helpful comments on an earlier draft greatly increased the clarity of this paper. My warmest thanks are due to the ringers, past and present, whose efforts in marking some 15,000 raptors in Britain and Ireland by the end of 1972 have made this paper possible. SUMMARY Almost 2,000 recoveries of 13 species of raptors have been reported either as a result of ringing in Britain (1,837 records of which 129 were abroad) or abroad and recovered in the British Isles (73). The more distant recoveries for 11 species have been plotted on maps, and these and additional information on recoveries and migration patterns, mainly gleaned from the literature, are discussed under each species. Brief summaries are as follows: GOLDEN EAGLE. Scottish birds seem to be sedentary. BUZZARD. Few British birds move any distance and only one has been found abroad. ROUGH-LEGGED BUZZARD. The one record in Scotland is from Sweden. SPARROWHAWK. Native British birds do not leave Britain. Migrants from the North Sea coasts and Scandinavia reach Britain on passage and during the winter. Females may winter slightly farther north than males. RED KITE. Young birds raised in Wales move southeast within Britain during their first autumn. A first-summer German bird has been recovered in Wales. MARSH HARRIER. The two most distant foreign recoveries point to West Africa as a wintering area for some British birds although others probably do not leave their natal area. HEN HARRIER. Most native birds stay in Britain but some winter abroad. Three breeding season recoveries show colonisation at ca. 250 km. (twice) and 800 km. from their native sites. MONTAGU'S HARRIER. The autumn movement through France is clearly shown. Some, possibly most, first-summer birds may remain in winter quarters. OSPREY. Scottish birds have been found wintering from North Spain to Mauritania. Young Swedish birds regularly occur on autumn migration and as immatures during the summer. HOBBY. There are two foreign recoveries and one in Norfolk from Finland : none throws any light on the winter quarters of the British population. PEREGRINE. No British birds have been recovered abroad although there are several long-distance internal movements. Some Scandinavian birds winter in the British Isles. MERLIN. Icelandic birds winter in the British Isles. Most native birds remain near their natal sites but some move south, sometimes as far as the Pyrenees. Young birds move farther than older ones. KESTREL. Birds from the northern part of the Baltic and from the Low Countries are well represented during the winter. British ringed pulli often move out of the country, mainly to northern France. First-year birds and birds ringed in the north of Britain are most likely to migrate. There is some interchange of breeding stocks across the North Sea. Vignettes by Rob A. Hume 285

29 BIRD STUDY REFERENCES BANNERMAN, D. A The Birds of the British Isles, vol. 5. Edinburgh and London. BELOPOLSKI, L Paper in Russian in Ekologiya, 3: BERMS, F Ayes Migradoras lbericas, fasc. 3. Madrid. VON BLOTZHEIM, U. N. G Hand buch der Vogel Mitteleuropas, vol. 4. Frankfurt. BROWN, L. and D. AMADON Eagles, Hawks and Falcons of the World. London. G0E-um F. and R. KUHK Beringungs-Ergebnisse an deutschen Adlern, Weihen, Milanen und Wespenbt. ssarden (Aquila, Circus, Milvus, Haliaetus, Pernis, Pandion). Die Vogelwarte, 16 : Gosms, F. and R. KtutK Beringungs-Ergebnisse an deutschen Wanderfalken (Falco peregrinus) und Batunfalken (F. subbuteo). Die Vogelwarte, 16: Hms, G Ergebnisse der Beringung von Rohrwesihen (Circus a. aeruginosus). Die Vogelwarte, 17: HEIDEMANN, J Vom Zug des Turnfalken (Falco t. tinnunculus), Wanderfalken (Falco peregrinus) und Baumfalken (Falco s. subbuteo). Der Vogelzug, 6: HILDEN, 0. and P. KALINAINEN Uber Vorkommen und Biologic der Rohrweihe, Circus aeruginosus (L.), in Finland. Orn. Fenn., 43: MEAD, C. J Ringed Peregrines in Great Britain. In Peregrine Falcon Populations; their Biology and Decline, ed. J. J. Hickey, pp Madison, Milwaukee and London. MEBS : T Ringfunde west- und nordwestdeutscher Mausebussarde (Buteo buteo). Auspicium, 2: MISSBACH, D Ringfunde der Rohweihe (Circus aeruginosus). Auspicium, 3: MOREAU, R. E The Palaearctic-African Bird Migration Systems. London and New York. NORDSTROM, G Ergebnisse der Vogelberingung in Finland in den Jahren Orn. Fenn., 40: OSTE.RLOF, S Fiskgjusens, Pandion haliaetus (L.), flyttning. Var Fagelvarld, 10: PERDECK, A. C. and B. J. SPEEK Ringverslag van het Vogeltrekstation. Limosa, 38: (Marsh Harrier map page 161.) PERDEcK, A. C. and B. J. SPEEK, Ringverslag van het Vogeltrekstation. Limosa, 40: (Sparrowhawk map page 75). RATCLIFFE, D. A The Peregrine Population of Great Britain in Bird Study, 19: RoDEsEcK, G Studies on Bird Migration. Var Fagelvarld, Supp. ScHELDE, Danske Spurvehoges (Accipiter nisus (L.) ) traekforhold. D.O.F.T., 54: SCHIFFERLI, A Vom Zugverhalten der in der Schweiz brutenden Turmfalken, Falco tinnunculus, nach den Ringfunden. Orn. Beob., 62: SNOW, D. W Movements and mortality of British Kestrels (Falco tinnunculus). Bird Study, 15: THOMPSON, A. L a. The migrations of British hawks (Accipitridae) as shown by ringing results. Brit. Birds, 51: THOMPSON, A. L b. The migrations of British falcons (Falconidae) as shown by ringing results. Brit. Birds, 51: VAURIE, C The Birds of the Palearctic Fauna: Non-Passeriformes. London. ZINK, G Ringfunde nordwestdeutscher Mausebussarde (Buteo buteo). Auspicium, 1: C. J. Mead, Ringing and Migration Section, British Trust for Ornithology, Beech Grove, Tring HP23 5NR, Hertfordshire. 286