The first 'Shikra' of BRC: hybrid or aberrant Levant?

After we posted about the first Shikra record of BRC on September 16th, we received several comments about the identification of this challenging accipiter. Some of them raised their doubts about the identity of the bird, and given our limited experience with this species and the lack of literature available here, we requested additional opinions for several specialist. Of those, the comments received from Barak Granit, Vasil Ananian and Dick Forsman were very helpful in assessing the pros and cons.

We also presented the observation and pictures to Andrea Corso, who arrived one day after this record at the Batumi Raptor Count. He compiled all the available information and has made an in -depth analysis of the bird, including a detailed examination on the wing formula and the plumage pattern. Andrea suggests the bird is likely to be an aberrant Levant Sparrowhawk or a hybrid of Accipiter brevipes (Levant sparrowhawk) and Accipiter badius (Shikra).

Andrea Corso:
"The Batumi’s Accipiter is for sure of great interest and a great bird!  Having better studied now the photos (but still not being at home, so I do not have the possibility to study the literature and photos concerning hybrids) I am more prone to think that this is an aberrant Levant Sparrowhawk or an hybrid brevipes x badius.

Picture by Johannes Jansen

Please check the examination table by Andrea Corso below for the details of the bird:

"FIRST STEP: Ageing of this bird favored an advanced 2CY  female (very dense rusty barring, wider than on male, as well as on remiges). Indeed the bird have the outermost primaries P10 – P9 retained which seems to show juvenile pattern, however also a very sun-bleached and abraded adult female in deleted moult stage type primary would appear like this, but the dark tip is very narrow and not as broad as on adult-type. The secondary S4 which is one of the best ageing field mark to age difficult birds is still juvenile-like with a narrower terminal dark bar (tip). The body is almost all in the first adult-type pattern.  Looking at the tail there are two moult waves visible, with the 1st moult front arrived to T3-T4 (or R3-R4) and starting again by the central feathers at T1 (or R1 ) (numbering them from the centre outward) so the bird could not be a 2CY. However, in the tail, many raptor could show two moult waves as the T1 its very often moulted alongside the 1st post-juvenile partial moult and the renewed (re-moulted) again  on summer of their transitional 2CY when complete moult start.

SECOND STEP: Having aged and sexed the bird we could now start to look at the ID characters:
The bird has been identified in the field by some very experienced birders, so I trust the jizz and the field looking was very attracting and interesting, with the iris colour which has been well observed by many birders. However looking at the fore above table of the main ID characters on in flight Shikra and Levant Sparrowhawk we could see that 1 character is in favour of Shikra (iris colour), while 3 are intermediate or of no value; on the contrary one character is in favour of Levant Sparrowhawk. It therefore could seems that the most likely ID is fitting Accipiter badius but the character in favour or intermediate/no value are of light importance, being very variable and of little relevance, while the wing-formula is the BEST and MOST important field character to ID these two species alongside with the dark versus pale wing-tip pattern. The latter in this bird is of no value as juvenile of both species have paler wing-tips and therefore they appear similar, also, some lightly marked female Levant could as well show paler wing-tip. Therefore we remain with the wing-formula, which favour without doubt a Levant Sparrohawk with wing-tip formed by P8-P7 with same length or even P7 longest, while P6 is clearly shorter than P-7 and appear not well fingered, being surely shorter than in typical badius. The wing-formula is hard to be judged due to the very spread wings and chiefly due to the “hand” and wings pushed very frontward for active soaring (in gliding or with no forward or frontward pressing would be much easier); notwithstanding the wing-formula is fitting good brevipes and is surely against badius.

Due to the odd iris colour and the other odd character I leave open the hybrid possibility, chiefly also because for the field experience of the observers."

Picture by Johannes Jansen

Additionally Barak Granit raised two points which may puts in question the identification of this bird as Shikra :  "the 6th primary seem to me too short for Shikra which should sticks out more, giving a '5th finger' (or half fingered) effect. And the bird lacks Shikra's longer mid secondaries  and also Shikra's shorter inner secondaries giving all together  parallel trailing edge.  If the iris was yellow (can't see it in the photos) than a hybrid should be considered."

Comments by Vasil Ananian: 
"I have looked a bit through literature and various photos, and the only pro-Shikra character I see on your bird is the wing formula - the wingtip is formed by three fingers, rather than two. But on your bird the wingtip, IMO, still differs from real Shikra's, which additionally has clear notch on inner vane of 7th (missing on your bird). The hybrids are supposedly very rare, and whether your bird could be one is a question. Otherwise I would opt for LS."
 
Dick Forsmans commented the following: "The inner wing is not broad enough for a Shikra, which has a particularly broad looking arm, therefore resembling a Sparrowhawk. The underwing barring and the breast markings are too dark and too contrasting compared with an adult Shikra, which looks more like a faded Sparrowhawk.  And finally, the wing-formula is not correct for Shikra, which has a wing like a Sparrowhawk, with a lost longest finger. This wing is too narrow and the wing-tip is too pointed for a Shikra, although the 5th finger (counting inwards) is a bit longer than on an average Levant.
As for the iris colour, to me the eye looks dark. Depending on the angle of the light sometimes even dark eyes may show a paler iris in photographs, but this is a photo-effect. The clear yellow iris of a Shikra would certainly have stood out more clearly."

For all counters and birders interested, we apologize for taking a to quick decision on this bird. And we would like to thank all specialists for their opinion, as well for this exciting bird for popping up and giving us the opportunity to get insight in its plumage details to start this interesting identification process.