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.
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| Figure 1 Possible Homeyer's Grey Shrike Lanius excubitor homeyeri |
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| Figure 2 Great Grey Shrike Lanius excubitor excubitor- first winter |
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.
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| 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.
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| 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.
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| Figure 5 Possible Homeyer's Grey Shrike showing partially spread tail |
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| Figure 6a Flight shot giving a better view of the outer tail feathers |
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| Figure 6b Flight shot with inset enlarged t5 with estimated extent of black |
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| 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.
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| 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.
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| 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.
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| 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.
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| 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.
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| Figure 11 Great Grey Shrike possibly homeyeri Beeley Moor Nov 2012 © Ken Smith |
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
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