04 October 2015

Hybrid Shrike or Turkestan Shrike? – Ash Shargiyah Development Company Farm (Fadhili)

Whilst birding the farm inland of Jubail we found an unusual shrike that looked like a Turkestan Shrike but lacked the strong white supercilium associated with the species and also lacked the obvious white primary patch. Its tail and rump looked dirty and less brightly coloured than most as well. For this reason I sent the photo to Alan Dean asking for his for his comments on whether this may be a hybrid, as he has always been very kind to me sharing his extensive knowledge. Alan wrote back saying the following “If the photo is colour accurate (always a proviso!) then I would suspect a hybrid. The rather grey crown and mantle have a ’karelini’ look but the rump and tail (especially the latter) look too dingy (insufficiently rufous) for a true Turkestan. As you’ll know, the central tail-feathers of Turkestan can be rather dark but what’s visible of the outers indicates that they too are decidedly dull. (P.S. Evgeny Panov regards all ‘karelini’ types as of hybrid origin, even those with strongly rufous tail and rump, but his opinion is not universally shared)”. In the field the bird had some rufous to the head (crown) and did not appear as grey as many of the hybrid Kerelini types I have previously seen so I asked Alan if Keralini have rufous colouration on the upper parts as I thought they were meant to have upper parts coloured grey like Southern Grey Shrikes? Alan replied “The illustration of Karelini by Bogdanov (1881), who described the type, shows a bird with rather pale grey (‘french grey’) upperparts and whitish underparts. The wings are quite black. There is an obvious supercilium. The tail, however, is fully rufous. Shrikes are encountered which match this appearance and it is how I interpret ‘karelini’. However, shrikes with somewhat greyer upperparts than classic phoenicuroides and lacking obvious rufous in the crown are often ‘lumped’ under the term karelini. Other terms applied to rufous-capped birds (= ‘ruficeps’) and grey-capped birds (= ‘caniceps’) – following Severtzov (1873) and Bogdanov (1881) – are rarely used now but perhaps preferable and it would appear that Bogdanov had a more specific appearance in mind when defining karelini. However, Panov (‘True Shrikes of the World’) includes in Fig. 15.4 a series of 20 specimens that he maintains illustrate a continuous gradation between typical phoenicuroides (on the extreme left of his series) and typical karelini (on extreme right of his series). He says that the intermediate birds have been attributed to karelini. This is part of the ‘evidence’ from which he concludes that karelini is a hybrid type. In your second photo (bottom of the two below photos) I can detect a slight rufous tinge to the crown – but it does seem slight. Overall the bird looks rather ‘grey and white’ and not like a true Turkestan. I think that Panov would regard this as a ‘karelini’ type (though of course I cannot speak for him) – but it does not match my own interpretation of matching closely the Bogdanov ‘type’ illustration. The undertail again looks very dull – it can be duller than uppertail in true Turkestan but still usually has distinct rufous hues (contra collurio, which generally has greyish undertail). So, I would suspect that your bird is a hybrid. Whether you interpret it as a ‘karelini’ is a matter of definition, as discussed above!”. Alan copied in a few people interested in hybrid shrikes and Brian Small and Magnus Hellstrom had a slightly different opinions saying they thought the bird was fine for a phoenicuroides. This was primarily due to the possibility of the colour of the back becoming greyer with wear and the contrast between crown colour and rear neck. Of course the supercilium is not what you expect for phoenicuroides, but then it should not be lacking in karelini either”. Lars Svensson on the other hand added “It is a bit bold to label this bird as a Turkestan Shrike, lacking a white supercilium and primary patch as it is. I am firmly in Alan's camp”. No matter whether this shrike is a hybrid or an unusually plumaged Turkestan Shrike it was a good bird to see and learn from and if the best and most knowledgeable birders cannot agree to whether it is a hybrid or not we obviously still have a lot to learn.