A candidate Homeyer's Grey Shrike - Matlock Forest

Local birder Steve Mann found a Great Grey Shrike in Matlock Forest on 21st November, I saw it the following day with Steve and Ken Smith. It spent several hours in a clear fell area perched on top of tall tree stumps and occasionally swooping down on prey items on the ground, presumably beetles and spiders although Steve had seen it take a Meadow Pipit the previous day and impale it on the tip of one of the stumps.

When perched it showed a large white patch at the base of the primaries and a second connecting patch at  the base of the secondaries which is a feature of the SE Russian race of Great Grey Shrike Lanius excubitor homeyeri referred to as Homeyer's Grey Shrike. 

There are no accepted records of Homeyer's Grey Shrike in Britain, although there have been several claims, and a detailed analysis of a bird seen at Blacka Moor, Sheffield in 2012 was posted on the Birding Frontiers website by the late Martin Garner and is still pending in the British Birds submissions files.

Figure 1 Possible Homeyer's Grey Shrike Lanius excubitor homeyeri

Figure 2 Great Grey Shrike Lanius excubitor excubitor- first winter 

Taxonomy

The taxonomic view of the Great Grey Shrike species complex was changed significantly in 2010 following an mtDNA study by Olsson et al and is still not fully resolved and can therefore be rather confusing.

Olsson proposed that the Great Grey Shrike should form a species group with three recognised sub-species; nominate excubitor, homeyeri and leucopteros. 

Shirihai & Svensson whilst recognising the above group include a number of other races within the overall Great Grey Shrike complex, including pallidirostris the so called Steppe Grey Shrike (a name formerly used for homeyeri!).

Anyway, I will stick with Homeyer's Grey Shrike which is also used by Shirihai & Svensson for Lanius excubitor homeyeri.

Distribution

The Collins Guide gives SE Russia and S Siberia, sometimes wintering on the Black Sea. Shirihai & Svennson quote SE Russia to north slopes of the Caucasus, S Siberia east to W Sayan, N Altai with short or medium range winter movements to S Central Asia.

However there is evidence to suggest that homeyeri is now being recorded regularly in eastern Poland and a paper in Ornis Polonica in 2017 concluded;

'As several Polish records of homeyeri, including observations from the breeding period and a few breeding records suggest, the contact zone between excubitor and homeyeri is likely to include the areas of eastern Poland.'

The same paper identified 29 wintering Great Grey Shrikes in the study area in NE Poland and commented that 2 appeared to be nominate excubitor, 2 were homeyeri whilst most individual showed intermediate phenotypic characters between excubitor and homeyeri or were potentially all homeyeri. The article is in Polish (with an English summary) so it's not clear what the phenotypic characteristics were that were used to separate the two.

There are however lots of photos of birds identified as homeyeri, both in the hand and photographed in the wild on the Polish bird sightings website Clanga.

Ageing

The adult Great Grey Shrike has a complete post nuptial moult in late summer (Jul - early October) whilst first years have a partial post juvenile moult at the same time which does not include primaries, secondaries, tail feathers or primary coverts and none or few greater coverts and tertials. In adults the bill base and lores become paler and this is most pronounced in females. 

The tertials and primary coverts looked to have a brownish tinge in strong light which indicate that the Matlock bird is probably in its first winter with retained juvenile feathers.

Absence of any barring on the underparts and all dark lores suggest that it may be a male.

Identification

Key features to distinguish homeyeri;

• Significant white secondary patch, 8-35mm on closed wing
• Garner states; all white outer tail feather (t6) and all white t5 or with limited black. Two all-white outer tail feathers is typical. Whilst Shirihai & Svennson say; tail on average has more extensive white, varying from t6 white with only small dark portion on inner web reaching dark shaft to all white t5-t6. Excubitor typically has significant black on t6 but some may show all white,
• Upper tail coverts noticeably paler than mantle, they are generally the same colour in excubitor or slightly paler,
• Scapulars paler than mantle and pale area more extensive than on excubitor,
• More white over the eye and ear coverts and extending over the bill as a narrow pale line. The grey of the crown and forehead generally meets the bill on excubitor and there is a variable amount of white over the eye and ear coverts.
• Paler upper parts, pale grey in homeyeri and ash grey in excubitor but this is very difficult to judge and varies with the lighting.
• Visible white bases to the outer tail feathers so the central black area forms a diamond shape on the spread tail rather than an arrowhead as in excubitor.

Figure 3 Possible Homeyer's Grey Shrike v Great Grey in flight

Figure 1 gives a side on view of the perched bird and shows the extent of the secondary and primary patches on the closed wing. 

The pale area over the eye and bill and pale scapulars are also visible and both areas appear to fade into the pale grey of the crown and mantle respectively creating diffuse pale areas. The mantle and crown are a paler grey than in excubitor and consequently there is less contrast with the whitish scapulars and supercilium ( as noted by Steve Mann on his write-up of the bird). The perceived colour of the upperparts varies with the light as can be seen from the various photos.

In flight (Figure 3) the extent of the secondary parch is much more evident compared with a typical Great Grey. Note that the pale upper tail coverts and broad pale scapulars are also evident compared to the Great Grey.

Figure 4 Possible Homeyer's Grey Shrike (L) v Great Grey Shrike showing paler rump and diffuse whitish supercilium

Viewed from the rear the pale upper tail coverts are apparent but the scapulars and most of the tertials are hidden under the mantle feathers.

I struggled to photograph the spread tail but saw the bird for a second time on 24th November and managed a photo of the partially spread tail Figure 5 and a further photo Figure 6a on the 12th December. Figure 6b was taken on 7th March 2021.

Figure 5 Possible Homeyer's Grey Shrike showing partially spread tail

The outer tail feather (t6) is clearly all white. The next feather in, t5, has a small area of black on the inner web extending to the feather shaft Figure 6a &6b. As noted above some black on t5 wouldn't preclude the identification as homeyeri but this may be too much.

Figure 6a Flight shot giving a better view of the outer tail feathers 

 

Figure 6b Flight shot with inset enlarged t5 with estimated extent of black

Referring back to the flight photo of Great Grey Shrike in Figure 3 where the tail is spread you can see that the black extends right across the base of the tail. Whilst the Matlock Forest bird in Figure 6a & 6b shows a white base to all but the central tail feathers, the outer feathers t5 and t4 showing the most against the all white t6. Comparing t5 to examples of excubitor the black is further down the feather, confirming the observation that there is a larger extent of white below the dark area at the base of the tail. The white at the base of t5 and t4 is visible beyond the upper tail coverts on the spread tail creating the almost diamond shaped black centre to the tail.

Figure 7 Possible Homeyer's Grey Shrike in flight

Figure 7 of the bird in flight gives another limited view of the underside of the tail and the upper photo shows the pattern of white in the secondaries also from the underside.

The extensive white tips to the secondaries appears to be another feature of homeyeri, not mentioned in the main identification guides. In homeyeri the secondaries are pale tipped with broad tips on inner secondaries s5, s6 and s7 (s7, s8 and s9 form the tertials). In first winter excubitor it looks like the white tips are restricted to the tertials whilst adult may show a little more white on the inner secondaries (perhaps increasing with age) but not the broad tips, which sometimes extend up the inner web of the secondaries, shown by homeyeri (Figure 9).

Measurements

Using photos to obtain measurements of live birds is clearly subject to some significant variability but, bearing that in mind, I think they can still provide valuable information.

I used the photo from Figure 1 and took the measurements as marked up below as Figure 8. I used bill depth as the reference measurement as I felt this was probably the most reliable. If the head is not exactly parallel to the observer it should still be the same depth whereas bill length is a more uncertain measurement and varies with the angle of the observer.

Figure 8  Location of measurements referred to in Table 1

Table 1 summarises the measurements and using the average bill depth of homeyeri. All the reference figures are taken from Shirihai & Svensson. 

Table 1 Measurements taken relative to bill depth from Figure 8 using homeyeri bill depth of 9.4mm

The measurements could apply to either subspecies, given the broad ranges reported for both, although BWP gives a narrower range for 30 1st year male birds measured, taken from the Netherlands in winter, with av of 9.2mm for the primary patch and range of 6-13mm. Whilst of the same group only 13 showed any secondary patch with an average of 5.9mm and range of 2-10mm. So the Matlock bird would be outside the range for both primary and secondary patches given for excubitor. Note that figures for the secondary patch in 1st winter females was slightly larger with an average of 7.6mm and range of 2-16mm although it was entirely absent in 50% of the sample of 30 individuals.

Discussion

The Matlock shrike shows all the features attributed to Homeyer's Grey Shrike but may have too much black on t5, the penultimate outer tail feather to be pure homeyeri?

It was still present in Matlock Forest on the 17th December although it can go missing for a week or so. In January 2021 a Great Grey Shrike was seen at Bonsall Moor (7km SW of Matlock Forest), it was seen on 23rd, 24th and 26th January and again on 28th February. I heard about the bird in early March and saw it there on the 7th and was able to confirm that it was the Matlock Forest bird (Figure 6b). I saw it again on 17th March and 3rd April and it was last reported on the 6th April.

The tail and secondaries certainly show a different pattern to the Great Grey Shrikes which were annual in the Matlock area for around 10 years up to 2015 and are the source of my photos in this article.

For any sub-species which intergrades there is a division at some point, with excubitor on one side and homeyeri on the other and it's difficult to say where the line falls and on which side this bird therefore sits but to me it looks closer to homeyeri than excubitor, exhibiting all the known features of homeyeri.

I contacted Tadeusz Stawarczyk of the Polish Rare Birds Committee he commented that over 300 Great Grey Shrike have been trapped and photographed (by Piotr Zablocki) in Poland from which they have developed criteria for the identification of homeyeri. He confirmed the various points noted above and stressed that the tail was the most important feature; t6 and t5 should be white or the latter may have a small amount of black on the inner web. Also he stressed the importance of the pale bases to the tail feathers creating the black diamond noted above.

On the basis of the photos of the Matlock Forest bird, whilst it shows all the features of homeyeri and probably originates from eastern Europe it may have too much black on t5 to be accepted as homeyeri on the Polish Rarities Committee criteria but is the closest documented example to homeyeri recorded in the UK to date.

Figure 9 Homeyer's Grey Shrike trapped in Poland © Piotr Zablocki

Figure 9 is taken from the Clanga website and this bird, identified has Homeyer's Grey Shrike, shows similar features to the Matlock bird with a similar amount of white in the primaries and secondaries and pale upper tail coverts. Clearly, you could argue that this may be an intergrade itself but it does show all the homeyeri features. I have read that there should be no step between the white in the primaries and the white in the secondaries but I think only the race from further east leucopterus is likely to show no step. Note that the appearance of a step is affected by the extent to which the wing is spread.

Looking further afield Figure 10 is Homeyer's Grey Shrike photographed in southern Kazakhstan and whilst this bird looks a little paler on the scapular's and paler over the eye the amount of white in the primaries and secondaries looks very similar to the Matlock bird and it seems unlikely that this could be an intergrade.

Figure 10 Homeyer's Grey Shrike Shardara Kazakhstan © Aska Isabekov

Interestingly, a local friend, Ken Smith, photographed a similar shrike on Beeley Moor in 2012 (Figure 11) which also looks to have some homeyeri features but the penultimate outer tail feather, t5, looks to have more black than the Matlock bird.

Figure 11 Great Grey Shrike possibly homeyeri Beeley Moor Nov 2012 © Ken Smith

It seems strange that no examples of Homeyer's Grey Shrike have been caught at the Bird Observatories on the east coast such as Fair Isle, Isle of May or Spurn.

 
Summary

A shrike was present in the Matlock area from 21st November 2020 - 20th March 2021, at least, which shows features of the SE Russian race homeyeri, Homeyer's Grey Shrike. 

In fact the Matlock bird conforms with the descriptions in Shirihai & Svensson, Garner and BWP in all key characteristics visible without trapping the bird. The acceptable presence of some black on t5 is noted in the their descriptions but not quantified. So on that basis the bird is homeyeri. 

But, the work done in Poland in recent years has gone further to quantify the acceptable amount of black on t5 in pure homeyeri which, if present, should not reach the feather shaft (Figure 9).

On that basis the Matlock bird does not appear to be pure homeyeri and may have some excubitor genes and it perhaps reasonable to speculate that this bird may originate from the contact zone in eastern Poland referred to in the Ornis Polonica article.

Although there are no accepted records of Homeyer's Grey Shrike in Britain there have been several similar birds in the UK and there are other records in Western Europe which have been accepted by their respective records committees.

It is surely only a matter of time before a pure homeyeri reaches the UK and hopefully this blog post will assist in its identification.

Acknowledgements

Firstly, thanks to Steve Mann for initially finding the bird and corresponding on its identity and also to Tadeusz Stawarczyk for his comments on the bird and for providing details of the work done on homeyeri in Poland.

References

1. Shirihai & Svensson 2018 Handbook of Western Palearctic Birds

2. Garner M 2015 Birding Frontiers Challenge Series - Winter 2014

3. Olssen et al 2010 The Lanius excubitor (Aves, Passeriformes) conundrum—Taxonomic dilemma when molecular and non-molecular data tell different stories

4. Zimowanie podgatunków srokosza Lanius excubitor ssp. w północno-wschodniej Polsce Ornis Polonica 2017, 58: 283–305

5. Handbook of the Birds of Europe the Middle East and North Africa (BWP) Vol 7 Cramp & Perrins 1993

Notes on the identification of a Brown Shrike - Johnny Brown's Common, North Elmsall

A shrike found at Johnny Brown's Common was provisionally identified as Brown (Lanius cristata) on the morning of 18th October but as photographs started to circulate the bird was reported as a possible Turkestan Shrike (also called Red-tailed Shrike, Lanius phoenicuroides ). As more birders saw the bird the 'headline' identity returned to Brown Shrike but still referred to the possibility of it being Red-tailed. 

The bird remained in the same area until the 22nd October and it is thought that agricultural work in the fields next to its preferred area on the 23rd may have displaced it. 

I had good views of the bird on 20th October in both direct sunshine and light cloud and took the photos referred to below with other photos provided by Tom Tams and Pete Garrity as noted below.

Old World shrikes have a complicated taxonomy which is not yet fully resolved but in relation to this bird there were two similar looking species to consider; Brown Shrike Lanius cristata cristata and Turkestan Shrike Lanius phoenicuroides phoenicuroides.

Figure 1 Brown Shrike Johnny Brown's Common

Age and moult

The bird was in good condition with a complete set of primaries, two tertials had been replaced on the birds right which were black centred and white edged and it looked to me that the shortest tertials were both missing, possibly just growing and the middle tertial was missing on the left wing. There were several feathers missing in the tail. 

The post-breeding moult in Brown Shrike is complex starting on the breeding grounds often involving the inner 2 or 3 primaries several tertials and tail feathers. Moult is then suspended and finished on stop overs or on wintering grounds in Oct-Nov (Dec). In Turkestan Shrike the post breeding moult is completed on the breeding grounds in Jul-Sept involving head, body, tertials and several tail feathers (Shirihai & Svensson). 

The fact that the bird was in moult is consistent with the identification as Brown Shrike.

The jet black mask, including the lores, and absence of any barring on the sides of the breast, flanks or mantle indicate that the bird is an adult male.

General appearance

Assessing the size and structure of a lone bird is notoriously difficult but to me the bird looked larger and stouter billed than Red-backed Shrike with a size and shape more akin to a long-tailed Woodchat Shrike. The tail looked narrow as well as long but as noted above several tail feathers were missing.

The underparts were off white with a yellowish tinge to the throat, flanks and undertail coverts. 

The upperparts were earth brown on the mantle and nape with a warm brown crown fading to paler buff above the bill. There was no sign of any white at the base of the primaries on the closed wing but some white was visible in flight on the spread wing.

The rump and uppertail coverts were a warm brown similar to the crown whilst the tail was more earth brown like the mantle. The tail lacked any sign of white bases in any of the feathers.

On the head a black eyestripe extended broadly from the ear coverts to the eye and narrowed in front of the eye to the bill base. A whitish supercilium extended from the bill, joining narrowly above the bill, over the eye where it broadened slightly ending short of the black eyestripe. The bill was extensively blue-grey with dark tip to the lower mandible and dark culmen and more extensive dark tip to the upper mandible.

The eye, legs and feet were black.

Identification

Adult male Turkestan Shrike has a striking white throat and supercilium with underparts that are either whitish or tinged pale orangey/pink. The eyestripe is broad and the black tends not to narrow on the lores creating a more even mask with the black often narrowly extending over the bill. 

Figure 2 Adult male Turkestan Shrike (left) © Steve Young/Birdwatch from Worfolk 2000¹ in a similar pose to the Brown Shrike (right)

The bill looks less bulbous compared to Brown Shrike and is usually black in adult males but can be pale based. 

The head features all support identification of the shrike as Brown. 

Underparts

The off white base colouration with yellowish tinges to the upper breast, flanks, undertail and underwing coverts are indicative of Brown Shrike, Turkestan Shrike should be whiter with pinkish or orangey tones. 

The colouration has doubtless faded when compared with Spring male Brown Shrike but supports the identification.

Figure 3 Underpart and underwing colouration

Upperparts

In adult male Turkestan Shrike the uppertail coverts and tail tend to be the same rufous colour and contrast with the browner mantle. In adult male Brown Shrike the mantle and tail are a similar brown with rusty uppertail coverts as was the case with the shrike at Johnny Brown's Common Figure 4. 

Figure 4 view of the upperparts

Primaries

Primary projection is similar for both species, some photographs and comments on the Brown Shrike indicated that the primary projection was too long. The bird had a habitat of lowering its primaries so that they sat well below the tertials thus exposing more primary tips extending from the base of the secondaries. There were indications of moult in the tertials, as noted above and it seems likely that these feathers were still growing. 

When the primaries were held below the secondaries the primary extension did not look particularly long, exposing 4 to 5 primary tips which is typical for Brown, Figure 5. A longer primary extension with more exposed primary tips could have been indicative of hybridisation.

Figure 5 Brown Shrike primary projection (left ©Tom Tams and right © Pete Garrity) Note the right hand image has been flipped to facilitate the comparison

Both Brown Shrike and Turkestan Shrike show emargination on p3-5 but this was not visible in the field or on photos.

Note also the effect of light on the plumage tones in Figure 5 the left hand image in sunshine whilst that on the right is in overcast conditions.

Brown Shrike has a shorter second primary than Turkestan. According to Shirihai & Svensson(2); p2 falls short of the wing tip by 7-13mm and on the closed wing falls between the 6th and 7th primary in 44% of birds measured, is equal to the 6th primary in 29% of birds measured , falls between the 5th and 6th primary in 20% of birds measured or is equal to the 7th primary in 7% of birds measured. 

In Turkestan Shrike p2 falls short of the wing tip by 4.5-10 mm and on the closed wing falls between the 5th and 6th primaries on 58% of birds measured, equals the 6th primary in 26% of birds measured or falls between the 6th and 7th primary in 16% of birds measured.

Figure 6 Comparison of wing formula

Clearly, the assessment of these features are intended for trapped birds. The second primary is hidden below primaries p3 and p4 which form the wing tip when the bird is at rest. I have been unable to locate any photographs which show p2 on a sitting bird but see the measurements made below on the bird in flight. 

Tail

As mentioned above several tail feathers were missing on the birds righthand side. If you look closely at Figure 3 and 7 and the left hand image in Figure 5 a growing feather is visible at the base of the tail on the right hand side.

Figure 7 Spread tail © Pete Garrity

Looking at Figure 7 nine tail feathers are visible including the short, growing t6 on the birds right as mentioned above. It looks like the outer 4 feathers on the birds left are full grown without any gaps. So the missing feathers look like t2 on both sides plus t3 on the right.

Brown Shrike has a very graduated tail with the outer tail feather (t6) only 70% to 80% of the central (longest) feathers. On Turkestan Shrike the outer feathers are 80% to 90% of the longest feather.

In Figures 7,9 and 10 the short outer tail feather, t6 on the birds left is clearly visible and is perhaps 70% to 75% of the length of the central tail feathers thus supporting identification as Brown Shrike.

In March 2015 a shrike was found in Mendocino County, California, the Mendocino Shrike. It was present for 8 weeks and was subject to a detailed analysis including 100 of photographs in order to establish its identity. They took a number of measurements from photographs taken in the field and compared them with data obtained from museum specimens Figure 8 (Pyle et al 2015 (3)).

Figure 8 Adapted from Pyle et al 2015 see caption to Figure 9 for definitions

I've adapted Table 1b from Pyle et al and renumbered the primaries with number 1 as the small outer primary in accordance with European practice. I didn't include their actual measurements as it is the ratio which is important. Clearly the tail measurements are restricted to the feathers on the birds left side as outer feathers are missing on the right.

Figure 9 Showing measurements from Pyle et al in white, yellow line shows intersection of p2 with p5/p6 © Tom Tams, a= p3-p2 and b= p3 to primary coverts. c= t5-t6 and d= t5 to point of tail feather insertion

Figure 10 Pyle et al measurements using upperside of wing

Results 

Figure 7 ratio a/b = 0.229 c/d = 0.245      Average = 0.237

Figure 8 ratio a/b = 0.244 c/d = 0.233      Average = 0.239

Ratio a/b came just within the range for Brown Shrike whilst ration c/d was slightly low for Brown Shrike but way above the range for Turkestan Shrike. Clearly, there are a lot of variables that can affect these figures but look like they could be of assistance in separating this group of shrikes if decent photographs can be obtained and it is not possible to trap the bird.

Summary

I have checked a range of features used to identify Brown Shrike; upper and underpart colouration, moult, head structure and markings and wing and tail shape all of which are consistent with the identification of the bird at Johnny Brown's Common as an adult male Brown Shrike. 

I have also used measurements described in Pyle et al to confirm that structural differences in the primaries and tail are consistent with this identification and can be used to separate Brown from Turkestan Shrike.

I saw no indication of any form of hybridisation and concluded that this was an adult male Brown Shrike of the nominate race cristata. 

Notes on the photos; the photos which are not attributed to other photographers have had no alterations or enhancement made to the colours 

Acknowledgements

Thanks to the finders of the bird at Johnny Brown's Common for the chance to study this bird. Thanks to Tom Tams and Pete Garrity for use of their photos and I recommend Pete's video, available on Youtube via this link if you are interested in this bird.

I'm happy to receive any feedback or comments on this blog. via Twitter or via email to andysbutler@aol.com.

References

1. Worfolk, T. 2000. Identification of Red-backed, Isabelline, and Brown Shrikes. Dutch Birding 22: 323-362.

2. Shirihai & Svensson 2018 Handbook of Western Palearctic Birds

3. Pyle et al 2015 The Mendocino Shrike: Red-backed Shrike (Lanius collurio) x Turkestan Shrike (L.phoenicuroides) hybrid. North American Birds Vol 69: 4-35

4. Birding Frontiers Challenge Series - Autumn 2014

5. Panov E On the nomenclature of so called Isabelline Shrikes Sandgrouse 31 (2009) p163-170

6. Ganpule P 2017 Red-backed, Brown, Isabelline and Red-tailed Shrike in Gujarat Flamingo Vol. XV-3 July - Sep, 2017

Siberian Lesser Whitethroat - Spurn 9th - 12th October

During a long weekend at Spurn with friends we came across a Lesser Whitethroat skulking at the base of a hawthorn hedge. Fortunately it remained in the same area over the weekend and I managed to obtain a series of photographs which confirm, as far as can be confirmed without DNA, that the bird was a Siberian Lesser Whitethroat (Sylvia curruca blythi). This race is now regularly recorded on the east coast in autumn and sometimes over-winters in the UK. 

Since an analysis of DNA from the various races of the Lesser Whitethroat was published in 2013¹ which indicated that blythi is not as closely related to curruca as previously thought and could be a candidate for a future split to form a species group with three other subspecies; althaea, halimodendri and margelanica as one species and curruca and minula in the other there has been increasing interest in identifying these birds, both in the hand and in the field.

Figure 1 blythi in profile, note brown mantle and buff flanks

Identification

The general impression was of the nominate race of Lesser Whitethroat (which I'll refer to as curruca and blythi for Siberian Lesser Whitethroat) in terms of size, structure and behaviour as it moved slowly through the bushes generally keeping low down. In brighter light the brown mantle was the most obvious feature and on closer examination the mantle colour continued up the nape fading to grey on the rear crown unlike curruca where there is a distinct division between the grey/brown of the mantle and the grey nape. This feature was most obvious when looking at the bird from the rear or when looking down on it (Figure 2), it was not so obvious when viewing the bird side on as in Figure 1 above. See also Figure 4 sent by Trev Charlton which show nominate curruca with the mantle colour extending on to the nape although it is less obvious as there is less contrast between the mantle and nape base colouration. Figure 4 also shows the colder, greyer tones of curruca compared to blythi. 

The next distinction from curruca was the colour of the underparts. In this bird the throat was off white but the flanks and lower breast were a warm buff separated by an off white lower belly and undertail coverts but the buff flanks looked to meet behind the legs whereas in curruca the whole of the underparts are off white. Slightly darker brown ear coverts and lores gave a masked effect but how strongly this appeared varied with the light and the viewing angle. 

Figure 2 viewed from behind, showing mantle colour extending on to nape

Figure 3 showing rear flanks and undertail

The tertials were dark centered with pale fringes which combined with the mantle colour brought to mind Common Whitethroat. Primary projection is said to be less than in curruca but there is apparently considerable overlap.

Figure 4 Lesser Whitethroat of the nominate race curruca © Trev Charlton October

A consistent distinguishing feature for blythi from curruca is the position of the tip of p2 against the other primaries in the closed wing. In blythi p2 is short and thus falls further away from the wing tip. This is a straight forward measurement for trapped birds but in the field the wing needs to be spread slightly to reveal p2. Fortunately watching this bird on and off over 3 days I did manage a photo with the wing slightly spread.

Figure 5 with wing slightly spread showing approximate position of p2

Clearly, there is quite a bit of room for error here depending both on the angle at which the bird is viewed and the extent the wing is spread as well as any damage to the tip of p2.

Table 1 Position of p2 in relation to tips of other primaries in closed wing. Figures are percentage of each sample (adapted from BWP)

The further p2 is out of alignment with the remaining primaries the shorter it will appear. Also the angle at which the line is drawn will also have an effect, I've tried to draw the line perpendicular to the primary shafts. Having said all that I think p2 falls around p6 which excludes curruca where p2 falls between p4 and p5 or at p5 in the majority of examples.

If you are not able to obtain DNA the final evidence required is the pattern of white on the outer tail feathers. 

Figure 6 in flight showing spread upper tail

I was unable to see any evidence of a moult limit (mix of juvenile and post juvenile feathers) in the greater coverts which would identify the bird as 1st calendar year but I think the pointed tail feathers are juvenile thus ageing the bird as 1st calendar year. The age is important as there is considerable variation reported between 1cy and adult birds. In its first year the race halimodendri has an all white outer tail feather (t6) so on that basis we can confirm that this bird is blythi. The nominate race curruca can have a similar outer tail pattern to blythi in its first year and both races may show white tips to the neighbouring feathers (t5 and even t4 and t3 in curruca).

I was interested to see if the pattern of the outer tail feather could be seen from the underside of the tail. It looks less distinct but the pattern can be discerned (Figure 7).

Figure 7 Pattern of the underside of t6 from below, note also off white belly

Bare Parts

The iris was brown, similar in colour to the mantle. The bill was dark with a bluish base to the lower mandible extending just over half its length. There was some reddish discolouration around the bill base from the blackberries it was occasionally seen feeding on. The legs and feet were black with paler bluish grey soles.

Call

It was heard to give a tacking call several times which sounded like curruca. No other calls were heard.

Behaviour

Over a four day period the bird was seen frequently in a hawthorn hedge and two areas of bramble extending to about 150m. Most of the time it was within 1m of the ground but occasionally climbed the hawthorns to over 2m. It was very active creeping through the low bushes and appeared to stick to one direction of travel making it possible to predict where it would appear when lost to view. Several times it climbed to the top of the brambles or low hedge and flew 20 - 30m when it would again set off in one direction and repeat the process. The tail was regularly flicked down, much like Common Chiffchaff although it was windy and this may have affected it behaviour in exposed positions. The tail movement emphasised a rather long-tailed appearance. On a couple of occasions it sat on, or close to the top of low scrub to preen.

Photographic Note:

The photos have been cropped and in some instances lightened but there has been no colour adjustments made either by the camera or in post processing.

Acknowledgements

Thanks to Roger Barnes, Mick Cunningham, Paul Doherty, Richard Hart, Vaughan Lister and Johnny McLoughlin and for input whilst watching the bird at various times and comments on its identification. Also Trev Charlton for his comments and use of the photos in Figure 4.

References

1. New insights into the intricate taxonomy and phylogeny of the Sylvia curruca complex Urban Olsson, Paul J.Leader, Geoff J.Carey, Aleem Ahmed Khan, Lars Svensson, PerAlström

2. Handbook of the Birds of Europe the Middle East and North Africa, the Birds of the Western Palearctic Vol VI

3. The Challenge Series - Autumn by Martin Garner

4. Handbook of Western Palearctic Birds Vol 1 Shirihai & Svensson

A few days in Bucharest 29th - 31st January

Incomplete - photos to be added

I'd read several reports of birders visiting Bucharest and was particularly attracted to the reports of Caspian Gulls and woodpeckers, both of which appeared relatively easy to see in the right conditions. For the gulls the' right conditions' were frozen lakes in Herastrau Park, which apparently occurs in most years but unfortunately not this one!
We stayed in the Bucharest Mercure which was about 3km from the park which I did walk several times but we also used Uber which was so easy and cost effective (about £2.50 for a one way trip).
Our first morning in the park was raining but we still managed several Syrian and Middle Spotted plus 2 Lesser Spotted Woodpeckers. 

The trees also held Nuthatch, lots of Tree Sparrows and several Hawfinch. There were a couple of feeders in the park which were a magnet for the Tree Sparrows and the numerous feral pigeons.
As mentioned the lakes were completely ice free and I counted at least 9 Pygmy Cormorant, which I'd probably not have seen if they had been frozen but unfortunately the gulls all appeared to be Yellow-legged. The following day I took some bread with me and managed to attract some of the birds a little closer and all of which proved to be Yellow-legged Gulls.
Walking back to the hotel I called in a Kiseleff Park which also had Syrian, Middle Spotted and Lesser Spotted Woodpeckers.
In the afternoon I visited Cismigiu Park which was closer to the hotel, it is smaller than Herastrau and the pond in the centre had been drained but I still managed a couple of Syrian Woodpeckers and several Hooded Crow.

Northern Goshawk flight identification and ageing in the UK - Revised and updated

This is a fully revised version of a blog I first posted in September 2015 with more photographs, particularly of sub-adult plumages. To make comparison easier and to facilitate the increase in the number of photos used I have copied individual photos on to a common background for the main illustrations. Whilst this may be less aesthetically pleasing I think it assists the identification purpose of the blog. 
I'm always happy to receive feedback and comments to andysbutler@aol.com or via the comments section at the end of the blog.

Despite an increase in the Northern Goshawk population during the 20th Century it is still a scarce bird and this, along with its generally reclusive behaviour, make it one of the hardest of our birds of prey to see. It is perhaps the difficulty of observing the Northern Goshawk combined with its size and striking plumage which makes it one of the most enigmatic of British birds and one that all birdwatchers get a thrill from seeing.

For more than two decades I have had the opportunity to study the Northern Goshawk through the year in the Derbyshire Peak District, and witness the various stages in the breeding, and non-breeding seasons. 
For such a large bird it is surprisingly elusive and whilst sightings are regular from December through March as birds start the display cycle they are very difficult to observe outside this period.
Despite seeing Northern Goshawks most days when I'm out in the first few months of each year I still get an incredible thrill from watching them. 
This article is aimed at helping those who are less familiar with them to confirm their identification and also for those with a deeper interest in bird identification and ageing to share my thoughts on the various plumages that can be identified in the field.

Figure 1 Northern Goshawk juvenile male (first plumage) Feb 2019

General considerations

To avoid repetition from this point forward I will refer to Northern Goshawk as Goshawk and Eurasian Sparrowhawk as Sparrowhawk other than in the Figure captions.

In order to clarify the various plumages associated with a Goshawk's age I have referred to First, Second, Third etc. Plumages, where First Plumage is the juvenile plumage the bird has when it fledges from the nest. I find the use of other terms such as the calendar year age of a bird confusing since in each calendar year after the bird has fledged it will have two plumages (either side of the summer moult). 

In a reasonable view and good light where plumage features are discernible, the only likely confusion is with the Sparrowhawk, particularly if the observer is not familiar with Goshawk. The female Goshawk has the size and build of a Buzzard (Figure 3) and should not normally cause a problem but males are considerably smaller, similar to Carrion Crow (Figure 2) and more likely to be confused with female Sparrowhawk although the latter is closer to Kestrel in size. Note that even for experienced observers size can be very difficult to judge in distant birds and it may not always be possible to confirm identification unless additional characteristics can be seen such as the flight or structural details noted below or some plumage features. I have watched very distant birds circling without flapping and have been uncertain which species I was watching. Clearly it helps if there are birds nearby to make a direct size comparison. 

Figure 2 Male Northern Goshawk with Carrion Crow

Figure 3 Female Northern Goshawk with Common Buzzard Feb 2019

The Sparrowhawk is a compact bird with short broad wings and a generally long square cut tail. 

The Goshawk has a more rounded tail, as the feather length decreases moving out from the longest central feathers (Table 1).  Although the closed tail can look square on the Goshawk (see Figure 11a for example) it is often possible to see the shorter outer tail feathers, particularly on photographs. Compare the tails on Figures 1 and 7 b & d for Goshawk with the Sparrowhawks on Figure 4 b & c. 

Note that moult may also affect the relative length of the feathers particularly in the autumn when feathers may be still growing. The central feathers are the first to be replaced so the outer feathers may still be growing after the central feathers are at full length. 

The Goshawk will often circle with the tail closed when it has a distinctive cross like silhouette with long wings and tail whilst the square ended tail of the Sparrowhawk can often be seen even in fairly distant views.

Table 1 Difference in length between central and outer tai feathers

Figure 4 Eurasian Sparrowhawk a, b, f, e juvenile, c adult male, d adult female

The flight of the Sparrowhawk is normally very distinct with circling and gliding interspersed with rapid flickering wing beats which are never seen in Goshawk. Both Goshawk and Sparrowhawk glide on flat wings (Figures 4e, 7f & 10b), unlike the Buzzard which holds its wings in a shallow V, and flaps with deep wing beats which gives the impression of its size.

Figure 5 Flight silhouette of Northern Goshawk and Eurasian Sparrowhawk not to scale

Without the labels in the silhouette above, even though I've reproduced the birds at a similar size it's fairly obvious that the Goshawk is on the left. The silhouettes are taken from photos of birds in similar positions but clearly not exactly the same, despite this I think there are a number of differences that are useful in the field;

• Where plumage details can be seen Sparrowhawk always shows barred secondaries. In Goshawk these are only present in First (juvenile) and Second Plumages. First Plumage Goshawk has a heavily streaked not barred breast but identification of Second Plumage Goshawk requires additional features,  
• The head of the Goshawk sticks further out, similar to Honey Buzzard when compared to Common Buzzard, and the neck base is broader,
• The Goshawk has relatively broader wings where they join the body, producing a bulkier appearance,
• The bulkier appearance is further enhanced by the thicker tail base on Goshawk which looks more pinched on Sparrowhawk,
• The shorter outer tail feathers of the Goshawk produce a rounded tail rather than the square ended tail of the Sparrowhawk.

The shape of Goshawk can also recall Hen Harrier and on more than one occasion I have seen a female Goshawk flying low over the moors where my first thought was that I was watching a Hen Harrier.

Moult

The Goshawk has a complete moult each year mainly during June to October. Females start the moult earlier than in males usually commencing during the egg laying or incubation period and losing 3 or 4 inner primaries over a short period. Males commence the moult a few weeks later and the moult is completed by the autumn.
In common with other large raptors not all the flight feathers are moulted each year. Figure 5 below gives a diagrammatic representation of a study of the moult in a captive female obtained as a juvenile in autumn 1982 under license in Germany. The moulted feathers were collected in each subsequent year (except 1983 when only primaries and tail feathers were collected) and the feathers moulted or retained identified.

Figure 5 Diagrammatic representation of the main flight feathersin the Northern Goshawk A=alulas, P= primaries, S= secondaries. The bar codes show which feathers were moulted (open cells) or retained (solid cells) each year between 1983 and 1989. The stippled cells represent those feathers for which no moult data were obtained.

Other than in 1985 all the primaries were moulted each year. There are no years when all of the secondaries are replaced and thus any bird older than juvenile will have at least some feathers in the wing grown the prior year. This is helpful in ageing immature birds.
The secondary feathers in the first post juvenile moult are dark tipped and more strongly barred than in subsequent moults. This makes these birds, which also have more coarsely barred underparts fairly easy to identify but a Goshawk encountered which has a one or two of these more heavily barred feathers most have completed it second post juvenile moult and is therefore in the second half of its third calendar year or the first half of its fourth calendar year.

Figure 6 Comparison of female Northern Goshawk in its 4th calendar year with an adult

The pattern of the barring on the primaries also changes with age in juveniles and birds having completed the first post juvenile moult the primaries have 5 or six visible bars, the barring is darker towards the tip and forms an even band in subsequent moults the bars become more triangular, broadest on the leading edge and narrowing to the rear.

First or Juvenile Plumage, first calendar year to second calendar year summer

Figure 7 Northern Goshawk in juvenile or first plumage b,c,d are males; a,g,e female

The Goshawk retains its juvenile plumage from fledging in July through to September of the second calendar year. I have seen a male in late June/ early July of its second calendar year still with a full set of juvenile remiges and retrices so there is a short period when recently fledged juveniles and 2nd calendar year birds still in juvenile plumage could be in the air together.

The young Sparrowhawk shows barring on the breast, although there may be some streaking on the upper breast, when it leaves the nest and therefore looks similar to the adult. Thus an accipiter showing  a streaked, rather than barred breast must be a Goshawk.

The juvenile in 7d has a single moulted breast feather just above its left leg which shows Second Moult barring.

The juvenile 7e has "flared" undertail coverts which has previously been noted as a diagnostic characteristic of Goshawk which is clearly not the case and may be seen in both species and sexes during the display period (see Sparrowhawk in 4a).

From fledging through to summer of the second calendar year the young Goshawk has an orangey-buff ground colour to the breast and underwing coverts with heavy dark brown streaking on the breast and underwing coverts. This colouration can show a distinct contrast with the pale ground colour to the primaries and secondaries which are heavily barred dark brown and forming a dark trailing edge to the wing.

The iris of the recently fledged juvenile Goshawk is a pale blue-grey colour which turns to yellow, like the adult birds by the end of the first calendar year.

Second Plumage, second calendar year autumn to third calendar year summer

During the moult in the summer of the second year the Goshawk's sheds its juvenile plumage and starts to look  much more like an adult. but viewed from the underside the flight feathers are heavily barred, similar to a juvenile. The breast is rather coarsely barred with barring coalescing on the upper breast. The colour of the underparts is generally browner than in the adult. From above the upperparts are a warm, slightly rufous brown. Barring on the tail is obvious when viewed from both above and below. 

The head pattern is less conspicuous than the adult with limited or no pale supercilium or dark ear coverts and the iris is yellow.

The bird in photo 8d photographed in early June of its third calendar year has started the moult to adult plumage having lost four inner primaries.

Figure 8 Northern Goshawk Second Plumage 

In Second Plumage the Goshawk is in its most Sparrowhawk like plumage with barred secondaries and breast. Identification is still fairly straightforward based on size, structure and absence of the 'flickering' wing beats shown by Sparrowhawk.

Third Plumage, third calendar year autumn to fourth calendar year summer 

Figure 9 Northern Goshawk Third Plumage

As noted under Moult above after the second post juvenile moult some individuals may be tentatively aged due to the retention of secondaries from the Second Plumage. Note however that the appearance of the underwing varies significantly depending on how it is lit. In strong light the underwing variations look muted but may be quite distinct in less direct sunlight. The head pattern is also less distinct and the barring on the underparts tends to be slightly coarser (the bars are wider) than in subsequent plumages. 

The iris is yellow.

Fourth Plumage, Adult, fourth calendar year onwards
After the third post juvenile moult birds are in adult plumage although with subsequent moults the secondaries become paler and more silvery, the primary barring becomes less distinct, barring on the underparts become finer, the ear coverts and crown darken in males and some females and the iris becomes more orange rather than yellow.

Figure 10 Northern Goshawk Adult Male 

There are no plumage characteristics that reliably separate males from females but in adult plumage males tend to have blacker ear coverts and a more distinct white supercilium but some females may also show these features.

Females are significantly larger as noted at the start of this article, they are also more bulky with broader chest and base of the wing and have a more aggressive look.

Figure 11 Northern Goshawk adult female

The females in photos 11a and 11b are the same bird taken in subsequent years, interestingly it has retained a gap in the secondaries so perhaps these feathers weren't moulted?

References

Reading C J, Molt Pattern and Duration in a Female
Northern Goshawk,  (Accipiter gentills),] Raptor Res. 24(4):91-97, 1990
Forsman D, Raptors of Europe North Africa and the Middle East, Helm Identification Series.