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FEATURE


season appears a steel blue sheen on the wings, which is more or less clearly visible depending on the angle of light fall. Quite clearly C. n. libs encounters a grey


back and a blue-grey rump. In combination with a lighter plumage compared to C. n. nigra this is the main distinguishing mark in my opinion. The size of the birds is very variable in


both subspecies and is not a good indicator for determination. Jörg’s tissue research shows that the length measured from the skull to the longest tail feather varies somewhat: • C. n. nigra 72 tissues from 29.4 to 39.8 cm, average length 34.9 cm.


• C. n. 28 libs tissues from 30.3 to 42.2 cm, average length 34.9 cm.


In my collection in both subspecies I see


large differences in size, both wild-caught and captive bred. The other two species, C. sibilans and C.


barklyi are on average 30 cm long, so a little smaller, although also individuals of some 35 cm in length have been found. There will be sporadic C. n. nigra for encounters with a lighter blue-grey. It struck me that this type has slightly less pattern in the wings. It is not excluded that this could be a hybrid form. The (live) specimens that I have seen were all wild caught birds. I have had a few of this type of bird in my collection and have observed similarly coloured birds in zoos in Madagascar and Portugal. Jörg’s tissue research also found that intermediate


BIRD SCENE 15


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