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Home , Clanga (bird), Great skua, Lesser spotted eagle, Merlin (bird), Steppe eagle, Tawny eagle

Flight identification of European raptors Steen Christensen, Bent Pors Nielsen, R. F. Porter and Ian Willis

PART 3. AND WHITE-TAILED In this part we deal with the two remaining genera of eagles, Aquila (five ) and Haliaeetus (one). All are found mostly in north, east and south-east and, excepting the two spotted eagles, are large or very large. The Aquila eagles may be divided into three groups. First, the group, with just the Golden A. chrysaetos, a very large species characterised by raised wings when soaring and, to a lesser extent, when gliding (see DEFINITIONS at foot of page 53). Second, the open country group, with the Imperial A. heliaca and the A. nipalensis, two large species which usually soar and glide with wings flat. Third, the group, with the Spotted A. and the Lesser Spotted A. pomarina, two smaller species which hold their wings down-curved in gliding and less obviously in soaring. The White-tailed Haliaeetus albicilla is the biggest and heaviest of all the European eagles, its size almost that of a Griffon fuhus (appearing in part 5); a breeding of and coasts, it is rarely found far from water and, like the Imperial and the Steppe in the second Aquila group, it soars and glides on flat wings. As emphasised previously, wing positions may alter in relation to wind and weather, but the normal head-on profiles of the three groups are shown in fig. 24.

Fig. 24. Head-on profiles of eagles: (A) soaring Golden Aquih chtysaetos; (B) soar­ ing/gliding Imperial A. heliaca, Steppe A. nipalensis and White-tailed Haliaeetus albicilla; and (c) soaring/gliding Spotted A. clanga and Lesser Spotted A. pomarina (but see text for details)

52 Flight identification of European raptors 5 3 Figs. 25 and 26 on pages 54 and 56 use mainly immature to illustrate the shapes and some of the distinctive characters of the six species from below, while the facing texts on pages 55 and 57 draw attention to particular points, indicate the broad differences between immatures and adults, and give brief outlines of the areas of Europe, the and north in which each species may be seen. Figs. 27-34 on pages 59-78 then illustrate the under- and uppersides of the six in various plumages and with different wing positions, while plates 10-16 emphasise some aspects in photographic form. A study of the sequences further justifies the division of Aquila into the three groups already referred to. All these eagles show great variation in plumage, but, unlike the buzzards and Pernis (part 1), this is related primarily to age, which can often be determined approximately in the . Unlike the White-tailed and, indeed, most other of prey, Aquila eagles are more contrasted and more easily identified in juvenile and other immature plumages, all becoming more or less uniform brown as adults. On the other hand, the only visible difference between the sexes is the slightly larger size of the female and, except possibly in the case of some Golden Eagles, this is not reliable as a field character. Unless otherwise stated, descriptions in this series refer to the European races, though the problems of are not usually relevant to field identification. Two taxonomic matters must be men­ tioned here, however. First, the Imperial has two races in Europe, nominate heliaca in the south-east and adalberti in , and these are separable in the field. Second, the is often considered conspecific with the of Africa and , but it is in fact rather different and we prefer to treat it as a full species. Finally, we remind readers yet again that this is essentially a working series for use and correction in the field. We welcome comments and constructive criticisms, and it is our intention to publish a summary of these at the end. We are also anxious to obtain more good flight photographs of the species to be covered in the remaining five instal­ ments of the series (see list in Brit. Birds, 64: 247), particularly of Saker Falco cherrug, Lanner F. biarmkus, Eleonora's F. eleonorae, F. columbarius, Black-winged Kite Elanus caeruleus and Goshawk gentilis (see also Brit. Birds, 65: 37). All correspondence should be addressed to R. F. Porter, The Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire, England

DEFINITIONS Hand Wing between carpal joint and tip (primaries) Arm Wing between body and carpal joint (wing coverts and secondaries) Soaring Circling flight often in a thermal of warm air on a straight course without or between wing beats 54 Flight identification of European raptors

Fig. 25. Typical undersides of Golden (immature), Spotted (immature) and Lesser Spotted Eagles Flight identification of European raptors 5 5

A. Aquih chrystutos (pages 58-60, plates 10-11), IMMATURE SHOWN. Large size and long, broad wings with bulging secondaries and narrower hand; fairly long, full, rounded ; head and neck protrude fairly noticeably, but not as much as Imperial. Immature dark blackish-brown with white patches on both surfaces of wings and tail; full adult entirely dark brown except for golden crown and nape, but younger adults often show immature markings which take many years to disappear. Only eagle that soars with wings invariably in shallow V (24A). Largely resident in mountain regions of , Fenno-Scandia and Baltic States across to Urals, and of south and from Iberia to Carpathians and Balkans, thence to , Caucasus and Middle East, also larger Mediterranean islands and north-; some dispersal in and Middle East in winter

B. Spotted Eagle Aquila cbnga (pages 61-64, piate isa). IMMATURE SHOWN. Smaller than Golden, this and Lesser Spotted being the smallest of the group; nevertheless, bulky with broad, rather square-cut wings and general shape not unlike small, short-necked, immature White-tailed; short tail and small head not protruding very far. Immature with conspicuous rows of spots forming white bars on upper- wing-coverts and often with white flash on carpal joint below (recalling Great Stercorarius skua); but adult entirely dark brown. Wings invariably held bowed down when soaring and gliding (24c). Summer visitor (but generally rare) to damp woods often adjacent to marshland in eastern Europe from south south to and east across Russia; short-distance migrant, but very few on passage at Bosphorus and other traditional migration places; more often seen in winter (but still very scarce) in marshy areas of Turkey and Middle East, also and south

C. Aquih pomarina (pages 65-67, plates 120-14). ADULT SHOWN. Slightly smaller and better proportioned than Spotted; wings narrower with more parallel edges (also six emarginated primaries whereas Spotted has seven, but impossible to count with certainty in field); tail longer, narrower at base and more rounded at end (not so wedge-shaped as Spotted); head protrudes slightly farther. Immature warm buff-brown on body and underwing-coverts, contrasting in good light with darker flight- and tail, while above it has rows of white spots on upperwing-coverts, white patch at base of primaries and white crescent on uppertail-coverts; adult grey-brown where immature buff-brown and may still retain pale patch at base of primaries and indistinct light U on upper­ tail-coverts. Soars and glides on slightly bowed wings (less so than Spotted). Summer visitor (far commoner than Spotted) to forest areas in east Europe from north Germany and Baltic States south to Balkans and east across Turkey to Caucasus; passage south-east Europe, Turkey and Middle East, April and end August to late October, but mainly second half September 56 Flight identification of European raptors

Fig. 26. Typical undersides of immature Imperial, Steppe and White-tailed Eagles Flight identification of European raptors 57 A. Imperial Eagle Aquila heliaca (pages 68-71, plates 15a, b). IMMATURE SHOWN. Large size similar to Golden and general shape not unlike extra big Lesser Spotted; wings broad and long; tail fairly long, almost width of wings, and usually slightly rounded at end; head protruding well. Immature below has streaked yellowish- brown body and underwing-coverts, and dark flight-feathers and tail with ill- defined but noticeable pale patch on primaries and faint white trailing edge to wings and tail, while above it is streaked yellowish-brown, paler on lower back, with dark flight-feathers, pale patch at base of primaries and yellowish bar along edge of greater wing-coverts; adult dark brown with creamy-white crown, white 'braces' and paier basal two-thirds of tail, while Spanish race adalberti also has white leading edge to upperwing-coverts. Soars and glides on flattish wings (24B). Spanish race (very rare) largely resident in south Spain and northernmost ; nominate race resident and summer visitor to of south-east Europe and Minor from Hungary to Jugoslavia through Greece, , Romania, south Russia and Turkey; passage at Bosphorus (small numbers) chiefly second half September and first half October, and a few winter on plains and marshes in extreme south-east Europe and Turkey

B. Steppe Eagle Aquila nipahnsis (pages 72-75, plates 15c, d, e). IMMATURE SHOWN. Size and proportions similar to Imperial. Immature bright version of immature Imperial with upperparts, underparts and most wing-coverts unstreaked pale clay-brown, lower back and rump creamy-white, greater upperwing-coverts black with broad white bar along tips, flight-feathers blackish-brown with white band along rear edge and large whitish patch on inner primaries, undersides of flight- feathers also dark with white bands along centre of wing and trailing edge and white patch on inner primaries, and tail dark with white tip; adult dark brown with small yellowish-brown patch on nape and slightly paler basal halves of flight- feathers. Soars and glides on flat or nearly flat wings (24B), but characteristically sluggish, more often perched on ground, roadside hummock or telegraph pole than other Aquila. Some resident on of and other parts of south Russia, and odd pairs may still breed in Romania; others move south in autumn through Caucasus to Turkey, Middle East and beyond; occasionally seen in winter in south-east Europe; closely related Tawny Eagle Aquila rapax resident in

C. White-tailed Eagle Haliaeetus alhkilla (pages 76-78, plate 16). IMMATURE SHOWN. Largest of the group, with very broad, rather square-ended wings; tail very short and wedge-shaped; head and neck protruding well beyond wings and powerful bill can be seen at some distance. Immature entirely dark brown but for white or yellowish-brown variegations on breast; transitional plumages may be rather mottled; adult dark brown with white tail and creamy-white head and neck. Soars and glides on flat wings (24B); will sit motionless for hours on ground near water's edge. Largely resident by rocky coasts or inland lakes in , Fenno-Scandia, Baltic States, Poland and Germany south to Balkans and Turkey; some birds wander in winter in eastern half of Europe west to and occasionally farther west 5 8 European raptors: Golden Eagle Golden Eagle Aquila chrysaetos (pages 58-60, plates 10-11) Silhouette Large eagle (compare 25 A with other drawings on pages 54 and 56), though often looking surprisingly lightly proportioned. Head noticeably protruding, but not so far as that of Imperial Eagle. Wings long and with edges not quite parallel, hand being a little narrower than arm so that trailing edge has distinct S-curve; when soaring, they look oval with bulging secondaries between narrower hand and pinched effect by the body. Tail longer and more ample than those of other Aquila eagles, length almost corresponding to width of wing. In head-on profile when soaring or, to a lesser extent, when gliding, wings raised in shallow V (24A on page 5 2).

Flight Soaring and gliding are most frequent modes of flight. In soaring, wings are raised and pressed slightly forward. In gliding, wings are less noticeably raised. In active flight, wing beats are deep and powerful. This is the most elegant flier of the large eagles and it has perfect control even in a very strong wind.

Identification Adult (27B, 28B) may be confused with adult Imperial (pages 68-71) or adult Steppe (pages 72-75) if the proportions are not seen well, but generally they are both heavier-looking and much less agile fliers (see discussions under those two species). Juvenile (27A, 28A) is unlikely to be confused with any other raptor, except perhaps Rough-legged Buzzard Buteo lagopus (part 1) in poor conditions because of its similar tail pattern. In fact, this is an easy eagle to identify, even in the rather featureless adult plumage, owing to its distinctive proportions with long and powerful wings and long and ample tail. It must be stressed, however, that a Golden Eagle often appears smaller than it really is and the observer can frequently be confused by its size unless another species is near for comparison. European raptors: Golden Eagle 59

Fig. 27. Juvenile and adult Golden Eagles Aqtdla chrysaetos from below. The juvenile (27A) is very distinctive, the underparts being dark blackish-brown with conspicuous white patches on the inner primaries and outer secondaries and on the basal half of the tail. Though these features are visible from both below and above, the wing-patches are usually less extensive on the upperside, whereas on the underside they may almost reach the body as a white point. Individual variation is fairly considerable, as is indicated by the photographs (plates 10, ua, d). The immature gradually loses the white patches as it progresses towards adult plumage (27B), which is attained after about six years. In both sub-adult and adult plumages the bases of the flight-feathers are often paler brown than the rest of the wings (plate 11b); the same applies to the tail-feathers, where the basal halves are often grey-brown and the terminal halves dark brown. Otherwise the adult is entirely dark brown below Fig. 28. Juvenile and adult Golden Eagles Aquila chrysaetos from above. The juvenile (28A) is dark brown with white patches on the inner primaries and on the basal half of the tail corresponding to those on the undersides, though the wing- patches are usually smaller above and rarely extend to the secondaries; again, however, individual variation is considerable (cf. plate 10a). Often the patches on the upperside are more oval than is suggested here, extending well back towards the rear edge of the wings. At close range the yellowish-gold of the crown and nape is visible and this remains through all ages. In the adult (Z8B) the body-feathers and wing-coverts become more reddish-brown and the latter have pale edges, giving the whole forewing a scaly appearance at close range. In adult and sub- adult plumages, as on the underparts, the basal halves of the flight-feathers and tail are slightly paler than the rest European raptors: Spotted Eagle 61 Spotted Eagle Aquila clanga (pages 61-64, plate 12a) Silhouette Bulky eagle looking not unlike miniature White-tailed, but still noticeably smaller than Golden (compare 25 A and 25B on page 54). Head comparatively small and not protruding very far. Wings moderately long and very broad, the latter effect accentuated by long secondaries which sometimes form a bulge on the trailing edge. Tail very short, often no longer than half width of wing, and appearing slightly wedge-shaped (but less so than that of White- tailed). In head-on profile when gliding, wings clearly bowed with drooping hands; when soaring, wings less obviously bowed.

Flight In soaring, wings are only slightly curved down, with the hands drooping below the level arms, and in a strong thermal they may even be held flat. In gliding, however, wings are distinctly bowed, with the primaries sometimes drooping even more than shown in 24c on page 5 2, and head-on there may even be a resemblance to a Ardea cinerea. In active flight, wing beats are heavier than those of other Aquila. On the whole, this is a very squat and rather clumsy- looking eagle in the air.

Identification Confusion most likely with Lesser Spotted (pages 65-67), but Spotted is more compact with smaller head and broader wings (compare 25B and 25c on page 54) and distinctly shorter tail which is often also slightly wedge-shaped (while that of Lesser Spotted is usually evenly rounded); its wing beats are deeper and stiffer, and its wings are more conspicuously bowed when gliding; at close range, it is darker and the juvenile looks almost black except for the often conspicuous white markings on its upperparts (29A). In view of its bulky shape (see also plate 12a), Spotted might possibly be confused with juvenile White-tailed (pages 76-78), but latter is much larger with conspicuously protruding head and more distinctly wedge-shaped tail. Confusion with adult Imperial (pages 68-71) should be prevented by that species' larger size, well-proportioned shape and colour patterns of tail, crown and nape, as well as its white 'braces'. 62 European raptors: Spotted Eagle European raptors: Spotted Eagle 63

Fig. 29 (pages 62-64). Juvenile, adult, variant adult and immature Spotted Eagles Aquila clanga from above and, overleaf, the first three from below. The juvenile (29A, 29E) is very dark blackish-brown with a purple gloss which, however, is rarely visible in the field. Above (29A), it is fairly heavily marked: prominent are whitish tips to the secondaries and greater coverts, which combine into lines along the trailing edge and centre of the wings; the median and lesser coverts are also tipped with whitish to a variable extent and these spots form fairly distinct, but often broken, whitish lines which are sometimes likened to 'rows of pearls'; the white uppertail-coverts show as a clearly defined U. The juvenile underneath (29E) is rather uniform, but there is invariably a paler area on the uadertail-coverts, and the greater coverts are tipped with whitish which forms a narrow and uneven line along each wing and often a more conspicuous white crescent around the carpal joint (this is particularly noticeable in 25B on page 54). All these white patterns gradually disappear as the bird progresses through the immature stages and the light tips to the secondaries are frequendy obscured through abrasion. An example of an intermediate immature from above (290) shows more uniform upperwing-coverts (but still the retention of the whitish tips to the greater coverts), the loss of the light tips to the secondaries, and a narrower white U on the upper­ tail-coverts. Apart from lighter areas on the tail-coverts both above and below, the adult (29B, 29F) is almost uniformly brown and, though this is actually slightly paler than the ground colour of the juvenile, it always looks extremely dark, often black, at a distance. The so-called 'fuhescms* variety (29c, 29G) probably accounts for only a very small percentage of the entire population. Typical individuals of this rare colour phase have all the body-feathers and wing-coverts on both upper- and under- surfaces creamy-white, contrasting sharply with the flight-feathers and tail which [continued on page 64] 64 European raptors: Spotted Eagle

[continued from page 63] are the normal dark brown. The resulting pattern is much like that of an adult Neophron percnopterus (part 5), but the Spotted Eagle is easily distinguished by its much more compact silhouette. Forms intermediate between the normal and 'fulvescens' are extremely rare: they could possibly be confused with juvenile Imperial or Steppe Eagles, but they never have the characteristic upperwing-patterns of those two species (see JID on page 71, 32D on page 75) and the shapes are very different European raptors: Lesser Spotted Eagle 6 5 Lesser Spotted Eagle Aquila pomarina (pages 65-67, plates 12b-14) Silhouette Noticeably smaller than Golden, of similar size to Spotted but better proportioned (compare 25c with 25A and 25B on page 54); proportions recall those of larger Imperial. Head not protruding very conspicuously, but appears larger than that of Spotted. Wings not so broad as those of Spotted and with the edges more nearly parallel. Tail slightly but noticeably longer than that of Spotted and evenly rounded at tip. In head-on profile when gliding, wings bowed with hands drooping; when soaring, wings level or only very slightly downcurved.

Flight In soaring, wings are held flat or with the hands very slightly drooped. In gliding, wings are more clearly bowed, but not nearly so strikingly as those of Spotted (and thus not so Heron-like). In active flight, wing beats are shallower and lighter than those of Spotted.

Identification Confusion most likely with Spotted (pages 61-64), but Lesser Spotted is better proportioned with larger head, narrower wings with more nearly parallel edges, and slightly longer and more evenly rounded tail. Lesser Spotted is also paler: head and upper- and underwing-coverts of adult (30E, 30B) are much lighter grey-brown, contrasting in good light with darker flight-feathers; wing-coverts of juvenile (30D, 30A) are warm buff and brown, similarly contrasting with darker primaries and secondaries, and though juvenile Spotted is much richer in white markings above, juvenile Lesser Spotted has more conspicuous white patches at the bases of the primaries on the upperside. From above, confusion is also possible with dark Short- toed Eagle gallicus (part 2), but latter has longer wings which are held flat or slightly raised when gliding and usually shows greater contrast between wing-coverts and flight-feathers. Juvenile Lesser Spotted may in some circumstances be confused, particularly on colour of upperparts, with immature or adult Steppe Eagle (pages 72-75), but latter is considerably larger with more protruding head, longer wings and longer and more ample tail. 66 European raptors: Lesser Spotted Eagle

Fig. 30 (pages 66-67). Juvenile and two adult Lesser Spotted Eagles Aquila pomarina from below and, opposite, juvenile and adult from above. The juvenile (30A, 30D) has characteristic warm-brown wing-coverts and body. Below (30A), other features are pale whitish undertail-coverts, yellowish-white tips to the secondaries forming a very narrow and hardly noticeable pale line along the rear edge of the wings, and whitish tips to the greater coverts producing a thin and often inconspicuous line along the centre of the wings; the tail and flight-feathers European raptors: Lesser Spotted Eagle 67

are darker grey-brown than the coverts, but the contrast may not be great. Above (JOD), the pale line at the tips of the greater coverts is more prominent and a crescent- shaped patch is formed by white shafts at the bases of the primaries; the light trailing edge to the wings is rarely distinct, but a yellowish-white U on the tail- coverts is often conspicuous. After four to five years the bird attains adult plumage (JOB, JOE), which is much more greyish-brown. The whitish markings on the under- and uppersides almost disappear except for a small patch on the upper surface of the primaries and a trace of the white U on the uppertail-coverts. Above (JOE), head, neck, mantle and lesser coverts become rather pale greyish-brown, most obvious on the crown and lesser coverts, contrasting with darker brown lower back, flight-feathers and tail. Below (JOB), the head and lesser coverts may not appear at all lighter or, at best, less obviously so. A pale variety (joe) is extremely rare, but we know of two specimens whose colour falls between those of a normal adult Lesser Spotted and the 'fulvescens' phase of the Spotted (29c, 29G) 68 European raptors: Imperial Eagle Imperial Eagle Aquila heliaca (pages 68-71, plates 15 a, b) Silhouette Large and heavy eagle, near Golden in size (compare 25A and 26A on pages 54 and 56). Head probably protrudes more than that of any other Aquila. Wings rather long and broad; some individuals, probably mainly juveniles, have longer secondaries producing an S-curve to the trailing edge and these often appear broader-winged than adults which have the front and rear edges practically parallel. Tail typically slightly rounded and fairly long, corresponding almost to width of wing, but through moult and wear it may appear fairly short and even square-ended, rounded or slightly wedge-shaped. In head-on profile when soaring, wings held flat; when gliding, wings usually level, but sometimes hands slightly lowered.

Flight In soaring, wings are held level and at right angles to body. In gliding, wings are usually level and, when moving slowly, at right angles to body or, when moving fast, angled with carpal joints pressed forward and hands pointing backward; in some conditions, however, hands may be held slightly below horizontal, recalling wing position of Lesser Spotted. In active flight, seems heavy and somewhat clumsy with rather floppy wing beats interspersed with glides; adults often appear less heavy and more agile than juveniles, this possibly being due to differences in breadth of wing (see above).

Identification Can often be confused with Steppe (pages 72-75), parti­ cularly on silhouette or in immature plumages. But juvenile (compare 31A and 31D with 32A and 32D on pages 73 and 75) lacks or has much reduced the juvenile Steppe's two broad white bands along centre and trailing edge of both surfaces of wings and end of tail, and less [continued on page 70]

Fig. 51 {pages i$, after plates, aniji). Juvenile, immature and adult Imperial Eagles Aquila heliaca from below and, on page 71, from above. The juvenile (31 A, 3ID) is pale yellowish-brown on the head, nape, neck, back, upper- and underwing- coverts, and underbody; in the nominate race, dark edgings form streaks on the nape, sides of neck and underbody, the last normally extending to the tibial feathers though sometimes they may be confined to the breast in an indistinct pectoral band (the Spanish race adalberti has no such streaking and, as a whole, has a paler, more rusty appearance). The lower back and rump are pale creamy-white forming a patch of variable shape and size. The tail is dark greyish-brown with a narrow yellow-ochre tip in fresh plumage, which is soon lost through wear. The yellowish-brown upperwing-coverts are speckled with brown and a yellowish band is visible at the tips of the greater coverts, while the flight-feathers are earth-brown with a whitish patch at the base of the primaries (}ID). On the underwing (31A) the mostly earth-brown flight-feathers are broken by paler greyish-brown inner primaries which contrast with the dark secondaries and merge into the dark outer primaries; as on the tail, a narrow yellow-ochre line may be visible on the tips of the [continued on page 70] European raptors: Imperial Eagle 69 70 European raptors: Imperial Eagle [continued from page 68] white on inner primaries; also generally has less blackish-brown flight-feathers and more mottled appearance, particularly on the upperwing-coverts, while at close range streaks on underbody are additional feature of nominate race. Immature in dark transitional plumage may be difficult to distinguish from corresponding stage of Steppe (compare 3 IB and 3 1E with 32B and 32E on pages 73 and 75), particularly as it often shows yellowish band along greater underwing- coverts (which, however, is white in immature Steppe), but pale rear crown and nape provide important field mark, while upperwing- coverts are generally far more mottled than those of any Steppe. Later, sub-adult loses or almost loses band on underwing, leaving pale nape and first white shoulder feathers as main characters. Adult (31c, 3 IF) shows these even more prominently and two-colour tail can then also be useful feature. Otherwise, Imperial easily separated from White-tailed (pages 76-78) by less protruding head, longer and more square-cut tail and slightly smaller size; and from Golden (pages 5 8-60) by generally more rectangular wings with parallel edges, as well as by soaring and gliding on level wings which are also usually not pressed forward. Differs from Spotted (pages 61-64) in longer and narrower wings, longer tail and much more protruding head, while its wings are rarely as bowed in gliding and wing beats not so deep and heavy. Proportions of outline similar to Lesser Spotted (pages 65-67), particularly in length and shape of wings and length of tail, but rather larger with more protruding head and generally squarer- ended tail. Juvenile can also be distinguished from juvenile Spotted and Lesser Spotted by plumage, being pale yellowish-brown, but 'fukescens' variety of Spotted (29c and 29G on pages 62 and 64) must be considered and separated mainly on outline.

[continued from page 68J secondaries, but this is likewise soon lost through wear. The immature plumage (3iB, 31E) is reached after about three years: dark brown feathering appears, probably first on the throat, breast, upper- and underwing-coverts and mantle, while the belly, tibial feathers and undertail-coverts are still yellowish-brown and the lower back and rump pale; the wing-coverts become mottled with dark brown, but the greater coverts continue to show a yellowish line above and a broad, diffuse, yellowish-brown band below, while the inner primaries may still be paler under­ neath; the rear crown and nape remain yellow-brown. The greater wing-coverts, rump and undertail-coverts still have pale tips in the sub-adult stage, which is otherwise dark brown with pale rear crown and nape, and white feathers beginning to show on the shoulders. The bird becomes fully adult (;31c, 3IF) after about six years: it is now blackish-brown with conspicuous yellow crown and nape, white on the scapulars and pale undertail-coverts (the Spanish race adalberti has conspicuous white lesser upperwing-coverts and more prominent white 'braces'); the tail is pale greyish-brown or silvery-grey on the basal two-thirds, contrasting with the blackish-brown terminal third, a pattern most evident on the upperside D

E

F 72 European raptors: Steppe Eagle Steppe Eagle Aquila ntpalensis (pages 72-75, plates 15c, d, e) Silhouette Large and heavy eagle, almost as big as Imperial (compare 26A and 26B on page 56); indeed, the nominate race from farther east in Asia, which is larger than the European subspecies orientalis, has a wing span corresponding to that of Imperial. Head protrudes almost as much as Imperial's. Wings fairly long and broad, with distinct S-curve to trailing edge: shorter primaries than secondaries give a pinched appearance where these feathers meet. Tail rounded and relatively long, typically almost corresponding to width of wing, though it may become particularly worn in this ground-perching species just before the moult. In head-on profile when soaring, wings held flat; when gliding, hands slightly lowered and arms either level or fractionally raised to give arched effect.

Flight When soaring, wings are held level and almost at right angles to body, though hands are often flexed. When gliding fast, wings are kinked with arms level and hands slightly lowered; when gliding slowly, as on migration, wings are slightly arched in position recalling Red Kite Milvus milvus (part 2). Active flight resembles that of Imperial in being heavy and rather clumsy, but it is a little less stiff-winged.

Identification Most easily confused with Imperial (pages 68-71), especially in immature plumages, and separation on silhouette is certainly difficult, though typical Steppe's wings have distinct S-curve to trailing edge and are more arched like Red Kite when gliding slowly; its wing beats are also more elastic. Juvenile Steppe is separable [continued on page 74]

Fig. 32 (pages 73, 7/). Juvenile, immature and adult Steppe Eagles Aquila nipalensis from below and, on page 75, from above. The juvenile (32A, 32D) is pale clay-brown on the head, nape, neck, back and upper- and underwing-coverts, and on the under- body, which is unstreaked. The tail is blackish-brown with a broad white terminal band. On the upperwing (32D), the greater coverts are black with broad white tips which form a prominent white band running the whole length of the wing on to the primary coverts; the secondaries are blackish-brown with broad white tips forming a conspicuous white band along the trailing edge of the wing and widening on the tips of the inner primaries; the primaries are also blackish-brown with a blurred whitish patch at the base of the hand, which merges into the white on the tips of the inner primaries. On the underwing (32A), both white bands are again present, but the one along the tips of the greater coverts is somewhat broader, especially on the primary coverts; the bases of the greater coverts are not black as on the upperwing and the inner primaries are paler, more whitish, than above; in certain lights the patch at the base of the upperside of the hand becomes translucent and [continued on page 74] European raptors: Steppe Eagle 73 74 European raptors: Steppe Eagle [continued from page 72] from corresponding plumage of Imperial (compare 32A and 32D with 31A and 3 ID on pages 69 and 71) by its two broad white bands along the centre and trailing edge of both surfaces of the wings, which contrast well with the blackish flight-feathers, and by its whiter inner primaries and whiter-tipped tail; it also lacks the other's prominent dark streaking and speckling on nape and sides of neck, mantle, upperwing-coverts and underbody. Immatures may be difficult to separate (compare 32B and 32E with 31B and 31E on pages 69 and 71), but immature Steppe often shows traces of the white band along the middle of the underwing (though immature Imperial frequently has pale yellowish-brown line on underwing and this may lead to misidentification); immature Steppe also lacks mottling on the under- wing-coverts and streaking on the underbody and, if these areas have moulted into the later uniform dark brown plumage and there are no traces of the white band on the underwing, identification is best based on colour of crown and nape, which are yellow-brown in Imperial by that stage. Adult Steppe (32c and 32F) differs more distinctly in plumage from adult Imperial by its dark crown and more diffuse yellowish nape, and lack of white 'braces', while Spanish Imperial {adalberti) also has white forewings. Indeed, adult Steppe is almost uniformly dark brown and so more resembles adult Spotted (pages 61-64), from which it differs mainly in silhouette and in flight: more protruding head, usually longer tail, and longer and narrower wings which are held more level in gliding flight. Well-marked juvenile Lesser Spotted (pages 65-67) superficially resemble juvenile Steppe. For distinctions from Golden (pages 58-60), see that species.

[continued from page 72] it appears as if the underwing has this too (as shown here). As the bird moults into transitional plumage, it gradually becomes darker brown and the white markings on the wings, rump and tail are reduced: the immature (32B, 32E) is then left with the band down the middle of each surface of the wing, but the one on the upperwing is little more than a line and only the one below is still broad. The sub-adult (not illustrated) lacks the line on the upperwing, but may show traces of the white band on the underwing and remains of white on the uppertail-coverts; all the wing-coverts are now dark brown and the basal parts of the flight-feathers are a little paler than the rest, as in the adult. Otherwise the adult (32c, 32F) lacks all traces of white on the wings; some individuals, possibly the majority, show yellow­ ish on the nape (not illustrated), which may be more or less well-defined as a small patch or spread into a diffuse yellowish-brown area merging into the dark neck and mantle. At all ages Steppe Eagles show a very prominent yellow corner to the mouth, which extends farther back towards the ear-coverts than in any other Aquila D

E

F 76 European raptors: White-tailed Eagle White-tailed Eagle Haliaeetus albicilla (pages 76-78, plate 16) Silhouette Large and heavy eagle, size as Golden or bigger (compare 25A and 26c on pages 54 and 56). Very large head and neck protrude as much in front of wings as tail does behind. Wings long, broad and with almost parallel edges. Tail short (a little longer in juvenile) and wedge-shaped (especially noticeable in adult), but appearing rounded when fully spread in soaring. In head-on profile when soaring or gliding, wings level and flat.

Flight In soaring and gliding, wings are held flat and almost at right angles to the body, though when soaring in thermals they may become very slightly raised, but never so much that confusion could arise vith Golden Eagle. In active flight, large size and broad wings may give heavy and clumsy appearance, but wing beats are often fairly rapid and shallow, and interrupted by long periods of soaring or gliding. When flying purposefully from one point to another, however, periods of gliding are often reduced in length and frequency.

Identification Size alone rules out other species apart from largest eagles and , and adult with white tail (33B, 34B) cannot be confused. Juveniles and other immatures can conceivably cause problems, but White-tailed is only European raptor with head protrud­ ing as much in front of wings as tail does behind (3 3A, 34A). Golden (pages $8-60), Imperial (pages 68-71) and Steppe (pages 72-75) also have rather protruding heads, but not so much (compare 2 5 A, 26A, 26B and 26c on pages 54 and 56). Only European vultures with which confusion is possible are Griffon Gypsfuhus and Black Aegypius monachus (part 5), but these have far less protruding heads. Wedge shape of tail (3 3 A, 34A) is usually a good field character, though it must be borne in mind that all Aquila eagles may have slightly wedge- shaped in worn plumage. Correspondingly, tail of White-tailed may become rounded or even square-ended through wear. Whitish centres to spread tail-feathers of second-year bird (3 3 A) are character­ istic. White-tailed appears heavier flier than Aquila eagles and, although in normal flight the wing beats are rather quick and shallow, they can be fairly deep and somewhat leisurely. Spotted Eagle (pages 61-64) often seems rather heavy in flight and in many ways has similar shape, but is much smaller with far less protruding head. European raptors: White-tailed 'Eagle 77

Fig. 33. Second-year and adult White-tailed Eagles Haliaeetus albicilla from below. The juvenile is blackish-brown underneath with a few pale rusty-yellowish feathers on the breast; the undertail-coverts often also appear yellowish-brown. From the second year (3 3A), and sometimes even earlier, the spread tail-feathers show whitish centres from below (also plate 16a); these immatures are somewhat variegated on the underwing-coverts and, with the breast still flecked with rusty-yellow, transitional plumages often have a rather mottled appearance (particularly notice­ able, too, on the upperparts). The tail becomes gradually whiter and by the sub- adult stage is white with only a greyish-brown wash on the outer feathers. The sub-adult otherwise resembles the adult (33B) which has all dark underwings and body apart from pale brownish to yellowish-brown upper breast becoming whiter on the neck and head; the adult's tail is completely white and in old birds the head may be almost pure creamy-white 78 European raptors: White-tailed Eagle

Fig. 34. Juvenile and adult White-tailed Eagles Haliaeetus albicilla from above. The juvenile (34A) has entirely blackish-brown upperparts. This plumage becomes rather variegated by the second year, particularly on the upperwing-coverts and back which may include some yellowish-brown or even whitish feathers; thus transitional stages often have a slightly mottled appearance. The adult (34B) is dark brown above, apart from its white tail and a pale yellowish-brown to creamy- white head (old birds having the palest heads) P h A T E i o. Young Golden Eagle Aquila chrysaetos, Sweden, J anuary (photos: Karl-Erik FriAren). Note the prominent white wing-patches and, above, that these are much larger on the undenting than the upperwing; just visible too are the white basal part of the tail, the scaly upperwing-coverts, and the golden nape (pages 58-60) PLATE II. Golden Eagles Aquila chrysaetos. Above left, immature, Turkey, May {photo: R. F. Porter) with smaller wing-patches than the bird in plate 10. Above centre, sub-adult, , December {photo: Arne Jensen), lacking white wing-patches, but with paler bases to the primaries and secondaries forming a lighter area that contrasts with the darker coverts. Above right, adult, Sweden {photo: Arne Jensen), showing all-dark plumage, large tail, and wings raised and pressed slightly forward in soaring. Right, the same immature as shown in plate 10 being mobbed by Hooded Crow Corpus corone comix, Sweden, January {photo: Karl-Erik ¥rid\en), giving further indication of the white on wings and tail; note also that the broad wings are rather narrower at the hands and show a pinched effect where they join the body, and that the tail is long and ample (pages 58-60) PLATE 12. Above, Spotted Eagle Aquila clanga in all-dark plumage, Sweden, October {photo: Soren Breitmg): very broad wings and short, wedge-shaped tail give shape like miniature White-tailed Eagle, but head is much smaller (pages 61-64). Below, Lesser Spotted Eagles A. pomarina (see also caption to plate 13): left, distinc­ tive immature plumage, , September {photo: Claus F. Pedersen); centre and right, gliding and soaring, Turkey, September (photos: R. F. Porter) (pages 65-67) PLATE 13. Lesser Spotted Eagle Aquilapomarina soaring {pboto: P. Van Groenendael and W. Suetens). This and the three opposite (plates 12b, c, d) show the narrower wings, longer and more rounded tail and larger head than Spotted (plate 12a). In gliding, the wings are bowed and hands drooped, less so in soaring (pages 65-67) PLATE 14. Four different Lesser Spotted Eagles Aquilapomarina, Lebanon, Septem­ ber {photos: Claus F. Pedersen): below right, gliding on bowed wings with hands drooping; remainder, soaring on nearly level wings. Again, these photos show the better-proportioned wings, longer and more rounded tail, and somewhat larger and broader head than Spotted (plate 12a); Lesser also has only six emarginated pri­ maries to Spotted's seven, but this is of dubious use in the field (pages 65-67) PLATE 15. Above, Imperial Eagles Aquila heliaca, Turkey, September, May {photos: M. J. Helps, R. F. Porter): long wings, longish tail (but less than Golden), and protruding head (pages 68-71). Below, young Steppe Eagles A. nipalensis, , February {photos: S. Christensen and Bent Pors Nielsen): white bands along middle and rear of wings and end of tail; lower left, creamy mantle and unstreaked wing- coverts, and patch at base of primaries merging into trailing edge (pages 72-75) PLATE 16. White-tailed Eagles Haliaeetus albicilla. Above left, immature, Fair Isle (photo: Bobby Tullocb) with whitish centres to dark tail feathers. Remainder, adults, , May-June (photos: above right, Gunnar Lid; below left, Eric Hoiking; right, P. Van Grosnendael and W. Suetens): note broad wings and large head almost as long as short white tail, which underlaps wings when fully spread (pages 76-78)