Articles - Getting to grips with Goshawks
Goshawk, Accipiter gentilis, juvenile (left) and adult (right), offset reproduction of watercolor.
Keith Vinicombe - Posted on 24 Mar 2011
Most birders probably have a mental list of their favourite birds but, if they had an equivalent one for their most frustrating, I bet Goshawk Accipiter gentilis would feature quite highly. Despite the fact that it has increased significantly in Britain in recent years, it remains difficult to see, even more difficult to see well and, perhaps most relevant of all, difficult to get past your local records committee. Not only that but, of all the species on the British List, Goshawk is probably one of the most frequently ‘strung’.
Top: adult female Goshawk Accipiter gentilis (Finland, January 2004). Perched adult Goshawks look very white below. Photo by Markus Varesvuo (www.birdphoto.fi). Centre: adult Goshawk A gentilis (Poland, October 2004). Goshawks are not easy to sex. Males are roughly seven-eighths the size of females. Photo by Rafal Gawelda. Bottom: juvenile Goshawk (Poland, August 2004). In this distinct plumage, the underparts are streaked, unlike those of juvenile Sparrowhawk, which are barred. Photo by Waldemar Krawowski.
Small numbers of Goshawks used to breed in Britain up to the end of the 19th century, but deforestation and persecution led to the species’ extinction. It became reestablished in the 1960s, apparently mainly from falconers' escapes and deliberate reintroductions (Marquiss and Newton 1982).
Marquiss (1993) stated that the Goshawks that started to breed in the mid-1960s were mainly small, central European birds, whereas those established in the early 1970s were descendants of much larger and paler birds, mainly from Finland. It seems likely that these populations have now become mixed. The latest estimate of the British breeding population is 250-300 pairs (see Ogilvie 2004) although, given Goshawk’s secrecy and habitat choice, it could well be higher.
It is in fact now common in certain areas, and I have had 36 sightings in the last seven years in one favoured area. The classic time to see them is in late winter and early spring, when they are displaying, but I have seen them at all times of the year, most reliably in good weather. The following is a personal view on Goshawk identification and record assessment, based on this experience.
Size isn’t everything
Being an accipiter, Goshawk does, of course, resemble Sparrowhawk A nisus but, given a half-decent view, not so much that you would confuse it. Standard text books tend to emphasise certain features – large size, bullet-shaped body, sturdy breast, prominent white undertail-coverts and the rather S-shaped rear edge of the wing – but personally, I find all these features to be of debatable significance.
The first feature to deal with is size. Goshawks are, of course, bigger than Sparrowhawks, and females are very big. Marquiss and Newton state that all males are considerably larger than any Sparrowhawk and three times as heavy(my italics). Cramp (1980) indicates that some Goshawks are longer and heavier than Common Buzzards Buteo buteo. BWP gives the wingspan of Goshawk as 135-165 cm, which would suggest that all Goshawks have larger wingspans than all Common Buzzards. Yet this is at variance with measurements given by both Forsman (1999) and Mullarney et al (2000), who give a much shorter wingspan of 93-120 cm, indicating that Goshawk averages about 10-15 per cent shorter-winged than Common Buzzard (although there is overlap).
This raises an obvious question: how do you judge the size of a bird under field conditions? Most Goshawks are seen either against the sky or low over distant woodland, and in such situations there is usually nothing nearby to facilitate an accurate assessment of size. I have only twice seen Goshawks actually with Common Buzzards, and the Goshawks appeared to be about three-quarters the size of the buzzards.
I also saw one, thought to be a male, with a Raven Corvus corax. The Goshawk was slightly shorter in length but the wingspan was only about three-quarters that of the Raven’s. In my experience, therefore, flying Goshawks do not look ‘buzzard-sized’, but rather appear intermediate in size between Sparrowhawk and Common Buzzard. This must surely indicate that the wingspan measurements given by Cramp are incorrect.
When separating Goshawk from Sparrowhawk, size is more problematic, as in both species the females are larger than the males. I have estimated that a male Goshawk looks about seven-eighths the size of a female. It is, of course, rare to see the two species together, but I have seen it twice. A Goshawk being mobbed by a Sparrowhawk looked about twice the size, while an escaped female with jesses circling with a male Sparrowhawk had a wingspan about double that of the Sparrowhawk.
Because of the distances at which I see most of my Goshawks – at least half a mile – and because there is rarely anything to compare them with, they strike me as being ‘big’ rather than ‘huge’. In fact, distant or lone birds high against the sky often do not seem especially big at all. The reason Goshawks tend to look big has as much to do with their flight as with their size. Goshawk has slow, deliberate, deep and rather elastic wingbeats in which the wings are clearly and evenly flapped both above and below the horizontal. This creates a rather flappy action, often described as ‘crow-like’. Although not totally accurate, this analogy is useful to remember.
When flying less purposefully, they may also give rather desultory flaps from the horizontal downwards, sometimes producing an almost cuckoo-like action. This is followed by a glide that is usually rather longer than a Sparrowhawk’s. Although Goshawk will sometimes flap faster, this is quite unlike the quick, energetic ‘flap-flap-glide’ of a Sparrowhawk, which contributes to the latter’s dashing and mercurial character. Another thing Goshawks do (like other large raptors) is to hang in the wind, barely flapping at all, sometimes for quite long periods.
Adult female Sparrowhawk A nisus (Sweden, September 2004). Clearly smaller and slighter than Goshawk. Furtive by nature, Sparrowhawks always land within the tree canopy. Photo by Markus Varesvuo (www.birdphoto.fi).
Adult female Goshawk A gentilis (Finland, February 2004). The white undertail-coverts are actually often most prominent from behind, as they may stick out either side of the tail base. Photo by Markus Varesvuo (www.birdphoto.fi).
The ‘flying crucifix’
Goshawk is far more than just a ‘big Sparrowhawk’, but how one perceives it depends on several factors, particularly the light, distance and what the bird is doing. One structural feature that I find very useful is Goshawk’s noticeably protruding head, and this is usually apparent at most angles. Another important feature is the rounded tip to the tail (this is noticeably square-ended on Sparrowhawk), but the obviousness of this depends on the angle of viewing and on whether the tail is closed or spread. When closed, the base of the tail looks quite broad and it tapers slightly to a narrower tip, but the rounded corners are usually clearly apparent if specifically looked for.
When soaring, the tail usually looks quite broad and rounded, often appearing strikingly paddle-shaped (or even diamondshaped). At a distance, Goshawks tend to look more ‘rakish’ than Sparrowhawk and the combination of the protruding head, the longer, more tapered wings (see below) and the long, rounded tail imparts the impression of a ‘flying crucifix’, rather than Sparrowhawk’s ‘flying T’ – another useful analogy to remember. There is something about the shape of a distant Goshawk that is vaguely reminiscent of Raven, not that the two are confusable! At closer range, the sturdier, heavier body may be more apparent.
Adult male Sparrowhawk A nisus (The Netherlands, October 2004). Note the slight build, squared-off tail, strongly barred flight feathers and orange underparts (pale buff in females). Photo by Ran Schols.
Whereas Sparrowhawk has relatively short and evenly rounded wings, I also normally think of Goshawk’s wings as looking distinctly paddle-shaped, particularly from a distance or when soaring. This effect is because Goshawk has longer wings with more tapering ‘hands’, with three or four primaries usually visible. In addition, the trailing edge of the wing shows slightly bulging secondaries, but personally, I do not find this particularly obvious. Wing shape is, however, a variable feature that depends on the angle of viewing and on what the bird is doing.
For example, in a descending glide or in the initial stages of a stoop, the primaries may be swept back, looking pointed and rather falcon-like. Indeed, there are times when Goshawk can suggest a rather short-winged Peregrine Falco peregrinus. When fully stooping, the whole of the wing is held in an S-shape, before hugging the wings close to the body during the final stages of the stoop, which may be almost vertical into the tree canopy. When seen back-on, the longer wings of Goshawk are very slightly upturned at the ends and, when soaring, I have even noticed them holding the wings in a very slight V.
On adults, a vital feature is the colour of the underparts and underwings. Because the barring on adult Goshawk is fine and because the ground colour is white, in reasonable light they always look uniformly whitish below. When in flapping flight, the underwings often ‘flash’ white from a distance. Although there is variation in the ground colour of Sparrowhawks, they generally look considerably duller, mainly as a consequence of broader barring, but also because of slightly buffer background tones (and in adult males because of the orange barring and shading on the underside).
In a closer view, Goshawks often look obviously capped or hooded, due to the dark head and ear-coverts, and these may show a sharp contrast with the whitish underparts. On average, this is most obvious on adult males, as immature males and many females show a more diffuse and subdued head pattern (Forsman 1999). The white supercilium, although a significant difference from Sparrowhawk, is a feature that cannot be seen in an average flight view.
The other feature that is often quoted is the prominent white undertail-coverts but, in my experience, this is obvious only on displaying birds (and Sparrowhawks also fluff out their white undertail coverts when displaying). In a normal flight view, the white undertail coverts are not obvious as they are sleeked down, and they do not in any case contrast with the rest of the underparts which are, as already noted, whitish. They are more apparent at closer range and in good light, but even then I would not describe them as conspicuous.
Adult female Goshawk A gentilis (Finland, November 2004). Note that the white undertail-coverts do not stand out against the pale underparts in most flight views. Photo by Markus Varesvuo (www.birdphoto.fi).
When displaying, however, they are deliberately fluffed out to the side and wrapped around the sides of the rump. This means that they are conspicuous not so much from below but from above and from the side, as they then contrast with the blue-grey or grey-brown of the upperpart plumage. At times, they can almost give the impression that the bird has a white rump. From above, the pattern is in fact strangely reminiscent of that of a flying Razorbill Alca torda, Common Guillemot Uria aalge or Long-tailed Duck Clangula hyemalis!
Another time when the undertail coverts may be obvious is when the bird is sitting in a tree and, again, the long, fluffed-out feathers are most prominent from behind as they stick out on either side of the base of the tail. Goshawks often sit in prominent positions in the tops of pine trees, particularly when surveying their breeding territories in spring. I have never seen Sparrowhawks do this (in my experience, they always land within the canopy).
Front-on, a perched adult Goshawk often appears as a large white blob in the treetops, suggesting a white-morph Gyr Falcon Falco rusticolus! This is because their strikingly pale underparts contrast not only with their dark upperparts but also with the greenery around them. In such positions the dark hood and white supercilium may be obvious.
Unlike in most flight views, perched Goshawks really do look big, mainly because there is something tangible – the trees in which they are perched – with which to gauge their size. I have seen distant perched Goshawks misidentified as Common Buzzards, but more frequently they are dismissed as broken branches or as rubbish stuck in the treetops!
In late winter and spring, both Goshawks and Sparrowhawks have similar displays, the most impressive being the so-called ‘sky dance’. Both sexes display in both species, and it is the female Goshawk that plays the key role (Cramp 1980). The display consists of slow, lazy, but exaggerated flapping in which the wings are raised and lowered well above and below the horizontal. This suggests a harrier or may even recall a European Nightjar Caprimulgus europaeus.
Juvenile Sparrowhawk A nisus (Sweden, September 2004). Note the heavily barred underparts and square tail, quite unlike juvenile Goshawk. Photo by Tomi Muukkonen (www.birdphoto.fi).
The most spectacular display includes a series of ‘switch-backs’ that consist of a fast, deep plunge (with slow-motion flapping) before shooting vertically upwards like a bullet, with wings closed tight to the body. The bird then levels out before repeating the display, often several times. Although both species slow their wingbeats in display, its larger size ensures that Goshawk’s performance is the more impressive. Sometimes, they seem to slow their wingbeats in more normal flight, again looking harrier-like, and this may leave the observer wondering whether the bird really is displaying, or just flapping slowly for the sake of it.
Fooling the committee
Goshawk is the bane of local records committees. To try to assess the scale of the problem, I obtained 20 descriptions that were submitted over the last 10 years to one particular records committee, in a county where Goshawks do not breed. Of these, six were accepted and the rest rejected, an acceptance rate of only 30 per cent. Personally, I found only two of the descriptions totally convincing.
What initially struck me was that the majority of records were submitted by unknown or relatively unknown observers. One such observer submitted no fewer than five Goshawk records in one year. In addition, a quick analysis of all the accepted records over the last 20 years revealed that just six observers accounted for more than half of them! What was equally apparent was that most local observers who could be regarded as 100 per cent reliable were not submitting Goshawk records at all. Not only do these figures appear to confirm Goshawk’s reputation as a ‘beginner’s bird’, but it also seems that certain observers are particularly prone to seeing ‘Goshawks’.
Another consistent feature was that nearly all the records were suppressed. This could be because people are, quite commendably, reluctant to disclose potential breeding sites, but I think that the real reason could be that most records start off as ‘possibles’ and evolve into ‘definites’ over a period of time. There is clearly an element of human psychology at work here. The most convincing description came from a very experienced observer who spends hundreds of hours every year in prime woodland habitat. The fact that this was the only Goshawk that he had seen in the county in the last 20 years is surely a telling statistic in itself.
Juvenile Goshawk A gentilis (Sweden, October 2004). Juveniles are quite buff below and, unlike juvenile Sparrowhawks, they are heavily streaked, not barred. Note also the protruding head and long, rounded tail. The secondaries bulge more prominently on juveniles than on adults. Photo by Markus Varesvuo (www.birdphoto.fi).
Most descriptions varied from non-existent, through poor to unconvincing. To give an example, one simply said: “Large bird of prey, larger than female Sparrowhawk, with flap-flap-glide flight." Even the better ones tended to repeat field guide clichés rather than providing genuine interpretations of what the observer actually saw.
What particularly struck me was the almost total lack of plumage detail recorded, this being in marked contrast to descriptions of Ospreys Pandion haliaetus, Red Kites Milvus milvus and Hen Harriers Circus cyaneus, which were quite detailed in this respect. Another peculiar aspect was the confidence with which many observers sexed their birds. Thus, descriptions of briefly seen distant silhouettes high in the sky were confidently sexed – invariably as females – even though there was nothing to indicate how their size was judged. This is at complete variance with my own experience, which indicates that distant Goshawks are very difficult to sex.
The lack of plumage detail has an additional significance. Given that, in the southern part of its range, it is the immatures that tend to move the furthest (Cramp 1980), it would seem highly probable that the majority of wandering birds would be immatures and that, in turn, the majority of those would be in juvenile plumage. Juvenile Goshawks are distinctive in that they have: 1) heavily streaked buff or ochre underparts; 2) pale fringing to the upperpart feathering; and 3) a slightly narrower ‘hand’, slightly more bulging secondaries and a comparatively longer tail than the adults (Forsman 1999). Yet none of the birds in the 20 descriptions was aged as a juvenile.
Female Sparrowhawk A nisus (Latvia, April 2004). The thicker brown bars and slightly buffer ground colour mean that, in the field, Sparrowhawks usually look much duller below than adult Goshawks. Photo by Tomi Muukkonen (www.birdphoto.fi).
Adult Goshawk A gentilis (Canada, April 2003). Note the greater bulk, longer paddle-shaped wings androunded tail. Photo by Yann Kolbeinsson.
Adult female Goshawk A gentilis Finland, November 2004). Note protruding head, rounded tail, taperedhand’ and whitish underparts. Photo by Markus Varesvuo (www.birdphoto.fi).
Other confusion species
Although Sparrowhawk is the traditional confusion species, three others need to be eliminated. Firstly, I have often witnessed people mistaking Common Buzzards for Goshawks. Although I can understand distant birds sitting in treetops being confused, flying Common Buzzards cannot be readily mistaken for Goshawks, as they are a different colour, a completely different shape and fly with their wings in a V.
A potentially more serious pitfall is provided by high-flying ring-tail Hen Harriers, which can look surprisingly Accipiter-like. Look out for the harrier’s more heavily barred underwing feathers, and white rump. Also, like Common Buzzard, a harrier should glide and soar with its wings in a V. The third is Honey Buzzard Pernis apivorus. This species too shows a protruding head and flat wings, and can appear somewhat Accipiter-like, but it is nevertheless long-winged and basically ‘buzzard-like’ in shape, and shows different plumage patterning.
Goshawks are clearly on the increase in Britain, but to see them you still need to visit selected tracts of mainly coniferous woodland. I would recommend visiting some of the well-publicised Goshawk viewpoints to gain experience of the species.
Given the current healthy state of our crow, pigeon, squirrel and rabbit populations, then – persecution aside – there would seem to be no reason why the species should not continue to increase and spread into suboptimal habitats. In some continental cities, such as Riga, Cologne and Amsterdam, Goshawk has recently started to colonise city parks (Hagemeijer and Blair 1997). Ultimately, there would appear to be no reason why it should not do the same here.
In the meantime, local records committees should adopt a very strict approach to claims away from known breeding sites. I would advise birders to exercise extreme caution when identifying this species away from favoured areas, and to claim only those individuals that are seen well – if you are at all unsure, then the bird was probably a Sparrowhawk!
Click on the links below to buy these books from the Birdwatch Bookshop.
- Cramp, S (ed). 1980. The Birds of the Western Palearctic. Volume II. Oxford University Press, Oxford.
- Forsman, D. 1999. The Raptors of Europe and the Middle East. A Handbook of Field Identification. T & A D Poyser, London.
- Hagemeijer, E J M, and Blair, M J (eds). 1997. The EBCC Atlas of European Breeding Birds: their Distribution and Abundance. T & A D Poyser, London.
- Marquis, M. 1993. In Gibbons, D W, Reid, J B, and Chapman, R A (eds). The New Atlas of Breeding Birds in Britain and Ireland: 1988-1991. T & A D Poyser, London.
- Marquis, M, and Newton, I. 1982. The Goshawk in Britain. British Birds 75: 243-260.
- Mullarney, K, Svensson, L, Zetterström, D, and Grant, P J. 2000. Collins Bird Guide. HarperCollins, London.
- Ogilvie, M, and the Rare Breeding Birds Panel. 2004. Rare breeding birds in the United Kingdom in 2002. British Birds 97: 492-536.