Red Kite on Cape Verde / Boavista 2023 (1 Viewer)

[jogresh]

One of the papers mentions several museum specimens. 🤔

 

[Andy Adcock]

The better question may be: does or did fasciicauda ever exist

I presume there are type specimens so a DNA test would confirm or otherwise.

 

[Andy Adcock]

he also sais that de Naurois mentions two birds in Lisbon Museum with unbanded red tails from a series of 20-25 birds (probably in several museums).
He thought that those two may have been close to the real fasciicauda- which would make the naming a bit strange....

Unless they are odd, M. migrans like the OP?

 

[christoph.randler]

Thank you again for the detailed responses, now back home, found in Snow & Perrins (Concise Edition): p.300: M. m. fasciicauda differs from nominate milvus in being smaller with shorter and more rounded wing and less deeply forked tail. Upperparts with less pronounced feather margins, underparts less brightly rufous with narrower shaft-streaks. Tail usually with 8-10 bars on central feathers, but these sometimes reduced. Inner webs of primaries basally pale grey with darker grey marbling, not white. Shows great individual variation, some more resembling nominate milvus, others more like black kite. M.m.fasciicauda may be hybrid of these species.

In the eight bird report of cape verde, Hazevort (2014) writes: "The situation of the magnificent frigatebird Fregata magnificens continues to be precarious, while a number of birds of prey are on the edge of extinction or have passed that mark already. This almost certainly applies to the Cape Verde kite Milvus fasciicauda, of which there have not been any reliable records for more than 40 years".

As far as I see, this contradicts the message in Hille & Thioally who reported some kites (see somewhere above in the thread): “….and only two individual Red Kites and one Black Kite were found in 1999.” – cited from their abstract.

Concerning the paper from Johnson (thank you for uploading it, Jörn), I see that they caught 5 black kites during August 2002 (which is well in the migration season?) and molecularly identfied them as black kites (but could be simply migrants, as the bird in question?)- but I have no access to the supplementary materials, probably they have some photos there?

 

[DickF]

To me this looks like a hybrid Red x Black, which I personally believe fasciicauda was too. Pro Red features are among other things the reddish upper tail, the below unbarred long primaries and the darker tail corners. Pro Black includes sparsely barred upper tail, wing formula with 6 emarginated primaries (although p5 is missing you can conclude certain attributes by analyzing the shape of p6!), head of BK type, shallow tail fork, rather uniform underbody etc etc. Also status of moult fits BK better.

It appears to be a widespread phenomenon that closely related vagrant species ending up in isolated locations start to interbreed, creating hybrid populations. The “Barbary Falcons” of the Canary Islands being another great example, with huge phenotypic variation ranging from Peregrine type birds to pure-looking Barbary Falcons. Island populations can be an asset and a pitfall.

 

[Andy Adcock]

To me this looks like a hybrid Red x Black, which I personally believe fasciicauda was too. Pro Red features are among other things the reddish upper tail, the below unbarred long primaries and the darker tail corners. Pro Black includes sparsely barred upper tail, wing formula with 6 emarginated primaries (although p5 is missing you can conclude certain attributes by analyzing the shape of p6!), head of BK type, shallow tail fork, rather uniform underbody etc etc. Also status of moult fits BK better.

It appears to be a widespread phenomenon that closely related vagrant species ending up in isolated locations start to interbreed, creating hybrid populations. The “Barbary Falcons” of the Canary Islands being another great example, with huge phenotypic variation ranging from Peregrine type birds to pure-looking Barbary Falcons. Island populations can be an asset and a pitfall.

Welcome aboard Dick, hope to see your contributions more often.

 

[christoph.randler]

Thank you very much! Yes, found some old hybrid papers about the two kites, will check next week in the office (see below), but what with the genetic evidence in the paper from Johnson et al. (2005)? They place the museum species of Cape Verde Kite within Red Kites but the study is based on maternal DNA (mitochondrial) so it would be better to have some additional genetic testing of these old records. Could possibly be some kind of uni-directional hybridization of individuals that have been "lost" on a distant island, seems a plausible hypothesis, thank you Dick, highly appreciated your and all other opinions.

Sylven, M. 1977. Hybridisering mellan glada Milvus milvus och brun glada M. migrans i Sverige 1976. Var Fa°gelvarld, 36, 38–44.

Wobus, U. & Creutz, G. 1970. Eine erfolgreiche Mischbrut von Rot- und Schwarzmilan (Milvus milvus×Milvus migrans). Zoologische Abhandlungen des Staatlichen Museums für Tierkunde Dresden, 31, 305–313.