Black-necked Grebe affected by progressive greying (not leucism)

By MaghrebOrnitho | 8 May 2015

A Black-necked Grebe (Podiceps nigricollis) affected by progressive greying photographed at Dayet Aoua in the Middle Atlas Mountains by Saad Rih. (It’s not a leucistc bird as stated before, see the comment in the update below).

Un Grèbe à cou noir touché par le ‘grisonnement progressive’ photographié à Dayet Aoua dans le Moyen Atlas par Saad Rih. (Ce n’est pas un oiseau leucistique comme indiqué précédemment, voir le commentaire dans la mise à jour ci-dessous).

Update:

We received the following comment by email from André Konter, a specialist in grebes and the author of Grebes of our World, published by Lynx Edicions in 2001:

Tom Conzemius informed me about the above record. I can confirm that this is not a leucistic grebe, but a grebe affected by progressive greying. It is a common mistake to confuse the genetically caused leucism and the age related progressive greying.

I have read the article by van Grouw (2006) which does not cite progressive greying. But thanks to André Konter’s comment above, I have found a second article by the same author (van Grouw 2013) which discusses the progressive greying (with examples) and the confusion it creates when distinguishing it from other colour aberrations like leucism. I have also found a comment by Konter himself about the grebes specifically. Here they are:

  • van Grouw, H. 2006. Not every white bird is an albino: sense and nonsense about colour aberrations in birds. Dutch Birding 28: 79–89.
  • van Grouw, H. 2013. What colour is that? The causes and recognition of common colour aberrations in birds. British Birds 106: 17–29.

Many thanks to André Konter for the comment and to Tom Conzemius for forwarding this observation to him.

Black-necked Grebe (Podiceps nigricollis) affected by progressive greying, Dayet Aoua, Morocco, May 2015 (Saad Rih Wildlife Photography).
Black-necked Grebe (Podiceps nigricollis) affected by progressive greying, Dayet Aoua, Morocco, May 2015 (Saad Rih).
A Black-necked Grebe in all its beauty, Dayet Aoua, Morocco, spring 2013 (Saad Rih Wildlife Photography).
A Black-necked Grebe in all its beauty, Dayet Aoua, Morocco, spring 2013 (Saad Rih).

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