Crested or Oriental Honey Buzzard and hybrids

On our first pilot count in 2007, which lead to BRC's birth, the first Crested Honey-buzzard (also referred to as Oriental Honey-buzzardPernis ptilorhynchus orientalis) was recorded on migration over Batumi. And during the 5 years of standardized counting in autumn, with more eyes and better understanding of the identification of this odd-looking heavy Honey-buzzard, this number increased. With caution and only if documented or very well seen, we were able to pick-out two individuals in 2009, four in 2010, eight in 2011 and at least twelve individuals last autumn season.

Now, we might have the first one documented on spring migration! But do we?  Are we absolutely sure about those well documented individuals? What are the key identification characters exactly?  Can we rule out hybridization or are all Cresteds actually intermediates?
We asked our identification-consultant
Andrea Corso to review all documented records, and present you his analysis on every photographed Crested / Oriental Honey-buzzard in Batumi! We'll start with a post on the adult males, they are supposed to be easy...

Spring male

hybrid male Crested x Eurasian Honey Buzzard - by Andrea VezzaniHybrid male Crested x Eurasian Honey Buzzard - on 4/05/2013 by Andrea Vezzani
Let's kick-off with the most recent spring record.
To quote Andrea on this one as a quick reply on the picture sent by his Italian friends: "ibrido maschio crestato x orientale, salutami tutti i miei amici li" 
As we are not well acquainted with Italian humor, we first thought he joked it might be a hybrid crested x oriental, which is twice the same species P.p.orientalis. But he did wanted to say a hybrid Crested x Eurasian! 
It's not an easy one, this chocolate brown phase.
According to the flight-feathers pattern (barring on remiges) the bird can be identified as an adult male. Chiefly because of the secondary pattern being unmarked white and very bright with almost no barring. This first step is very important in order to may proceed in the identification process.
Andrea Corso: "For a male, the bird shows mixed characters of both orientalis and apivorus. Pro Crested, it has a long P5 and P6, a bold terminal bar to tail (but not bold  enough for a male), no carpal apparently (but often appears so in dark morph apivorus). Pro Eurasian is the narrow wing, primary and secondary barring, head and general jizz, second inner bar to tail.... ID conclusion: most probably a hybrid Crested x Eurasian Honey-Buzzard"

This is consistent with the opinion of Dick Forsman, who we also consulted on this bird: 
"This bird, an obvious male, shows in my opinion mixed/intermediate features between European and Crested Honey-buzzard. The primary banding suggests Crested, while the band in the secondaries does not, the tail banding is not good enough for Crested, wing-formula shows a rather long sixth finger, but the hand itself is rather narrow lacking the proportions of Crested, and so on. This is in my opinion an intergrade between the two species, which unfortunately appear to be quite common among the birds seen in the Middle-East and C Asia."

Easy ones
adult male Crested Honey-buzzard - by Michele PannucioAdult male Crested / Oriental Honey-buzzard - by Michele Pannucio
So let's look back on the previous adult male records on autumn migration. This one from 2011 is easier, as this one is probably the most typical bird photographed in Batumi to date.
Andrea Corso: "With no carpal patch (only a small little dark spot at the wrist junction), a tail from below appearing all black with a pale band due to the very broad dark bars (or bands), grey head with dark iris (typical of male adult), complete and well marked gular patch with lateral gular stripes and necklace, very well fingered 6 primaries (or even a six and 1/2). ID conclusion: clear adult male Crested Honey-Buzzard."

 

adult male Crested Oriental Honey-buzzard - by Jan ransonAdult male Crested / Oriental Honey-Buzzard - by Jan ranson
Next one is a nice capture of a bird's upper side, passing station 2 on eye level in 2010.
Andrea Corso: "This is a typical adult male Crested, but showing how much the tail terminal band can be variable!! In fact, in this bird the tail bands are not much broader than in some well marked adult male Honey Buzzard. This  high variability is also supported by measurements of the tail's terminal band on museum specimens (Corso & Scuderi 2012). All the other characters are typical for an oriental, including the dark iris. ID conclusion: perfect adult male Crested / Oriental Honey-Buzzard."

 

adult male Crested Honey-buzzard - 11/09/2012 by Morgan BochAdult male Crested/ Oriental Honey-Buzzard - 11/09/2012 by Morgan Boch
This one is one from last autum, digiscoped by Morgan Boch.
Andrea Corso: "This bird is a pretty typical adult male Crested Honey-buzzard with typical remiges pattern, and an all looking black tail with a middle pale band across. No carpal patch and wing-formula well fitting orientalis. 
ID: this bird is surely an adult male Crested / Oriental Honey-Buzzard."

 

 

 

 

Blurry one

adult male Crested Oriental Honey-buzzard - by Aki Aintila Adult male Crested Oriental Honey-buzzard - by Aki Aintila
Andrea Corso:
"This bird could be aged as adult while sexing it is difficult on the low quality photo, yet remiges and tail pattern point toward a male. The quality of the photo is so low that avoid an in depth analysis, yet the primary and secondary barring (a middle bar well marked, broad and well visible in both the primaries and secondaries, in the right position and width) as well as the tail pattern (an almost wholly black looking tail with a pale middle bar on it) will fit well a Crested HB. Also, the P5 fingered primary is rather long and narrow, obviously projecting past the P4. ID conclusion: the more likely identification for this bird, is adult male Crested / Oriental Honey Buzzard, there are no apparent reason to believe is not a pure one."

 

 

 

Dark phase hybrid?

dark phase hybrid Crested x Eurasian Honey-buzzard - 11/09/2012 by Albert De JongDark hybrid Crested x Eurasian Honey-buzzard - 11/09/2012 by Albert De Jong
Andrea Corso:
"This dark phase is a tough one. Again, according to the barring on remiges this bird can be aged as an adult male. Again, this step is very important in order to may proceed in the identification process.
PRIMARY PATTERN: the barring on primary seems to be closer to the one found in Honey Buzzard (Pernis apivorus) with in fact the inner bars closer to the coverts (“hand” base) being proximally distributed near the wrist instead of distally as in typical adult male Oriental Honey Buzzard, where the inner dark bars are better distributed along the fingered primaries, so being closer to the dark tipped “fingers”.
SECONDARY PATTERN: barring on secondaries is also closer to Honey Buzzard rather than to a typical OHB where there should be 3 dark bars visible (trailing edge, middle and proximal bars) with the middle one pretty well marked and visible all along the secondaries reaching the body. There is a certain amount of variability on this characters as highlighted by Corso & Scuderi (2011), this chiefly regarding Honey Buzzard with secondary pattern as on Oriental Honey Buzzard but more occasionally viceversa.
TAIL PATTERN: the terminal black band is quite broad could be fitting an adult female OHB but it is at the narrowest width for an adult male; indeed, there is a certain amount of variability on the terminal band (or bar) as highlighted by Corso & Scuderi (2011) and this character alone does not necessarily indicate an hybrid origin or a back-cross hybrid as reported by Faveyts et al. (2011). In fact the middle bar is usually the clinching feature and in this bird is rather large being usually narrower on most presumed (or proven) hybrids. Still the unmarked and bright gap between the middle and the terminal bands is too wide for a typical OHB, and this combined with the rather narrow terminal band, the remiges pattern, the wing-formula (see further down) make the bird appearing very suspicious.
WING-FORMULA: although the “hand” appear rather large looking, still the 6th “finger” (P5) it is not very well protruding, most notably on left wing (while on right wing, P4 seems to be re-growing somehow) and in between the correct length of projection in OHB and on HB.

ID: the more likely identification for this bird, at least the more conservative, would therefore be a hybrid or back-cross hybrid. At least as long as the westernmost populations of  Crested Honey-buzzard (P.p. orientalis) would not be studied to test the range of variability of them."

To conclude, the identification of Crested Honey-buzzards is far from easy, and adult males aren't always that straightforward as you might think. The amount of variation, especially in the most western population of Crested Honey-buzzards needs more study. And especially since we know those hybrids are around, we are very keen on learning more about them. Please comment on this article or let us know if you have useful pictures and literature, through our facebook-page or the contact form.  And for the keen, a review of the adult females will follow soon!