Expert Answers: Why the White in the Great White Redpoll

Albinism, Leucism and Vitiligo

Th posting on the Great White Redpoll has stimulated some fascinating and educational responses. No more so than that supplied by Hein van Grouw, Bird Group Curator at the Natural History Museum, Tring. Thanks Nils van Duivendijk for contacting  Hein, to Hein himself (see below) and all those whose responses are in the comments section below the first post. Worth a read.

 

“This Redpoll is indeed interesting but certainly not rare. There are many mutations which can cause a change in the plumage pigmentation and therefore an aberration in the colour. All kind of colour names are seemingly randomly used, now and in the past, to identify mutations in birds. Most commonly, and most often wrongly, applied is the name Albino or Partial Albino. This name is widely used for all sorts of different colour aberrations, but in only a few percent of the cases it is used correctly. Due to the mutation, an Albino is unable to produce melanin pigments at all. A mostly white bird which nevertheless shows some form of melanin pigmentation is never an Albino, by definition.

Therefore ‘Partial Albino’ does not exist and is a contradiction in terms.


This latter name is often used for what is in fact Leucism. Leucism, from the Greek Leukos = white, can be defined as the partial or total lack of pigments in feathers (and skin). The lack of pigment is due to the congenital and heritable absence of pigment cells from some or all of the skin areas where they are normally present and where they normally provide the growing feather with pigment. Depending on the sort of leucism the amount of white feathers can vary from only a few white feathers (= partial leucistic) to totally white individuals. The totally white individuals always have colourless skin as well. Partial leucistic birds can have normal-coloured bill and feet depending on where the colourless patches occur on the specimen.

However leucistic birds always have normal coloured eyes.


There are however other congenital causes for pigmentless feathers. Whereas leucism is visible after hatching, vitiligo (also called progressive greying), for example, is a progressive condition that arises after a certain age. Vitiligo is defined as the heritable progressive loss of pigment cells with age. From a certain age, when the progressive loss starts, the bird will get more white feathers after every moult. This is not uncommon in birds and it is known in Jackdaws and Blackbirds for example. And it seems it is not uncommon in Redpolls either as I have seen several identical specimens over the years.”

Hein van Grouw, Curator, Bird Group, Dept. of Zoology, The Natural History Museum, Tring.

6 thoughts on “Expert Answers: Why the White in the Great White Redpoll

  1. Victor Boullet

    Hi,
    On the 10th of November I observed what I thought was a Lesser Redpoll, which had strange colouring, the head was completely white with a red, pink spot on its forehead.
    Otherwise the colour was normal,
    The sighting was at Nannestad Norway.
    I took a photo.

    Reply
  2. Louisa Rowland

    I’ve had the exact same white redpoll here too and have taken many pictures. He/she looks just like the picture with the orange head, not pink. I’m in Northwestern Ontario, Canada. I wondered what the heck kind of bird it was, glad I got to take some pictures and also watch it hanging with the common redpolls. He/she sure stands out in a crowd!!
    Louisa

    Reply
  3. abdul majeed badrudin

    Dear Ms/Mrs Hein van Grouw,

    I am a canary breeder in the new colour section and specialist breeder of Isabel Satinet canaries after winning the nationals in South Africa. I belong to to the RCB (Reef Cage Bird) society which is affiliated to the SANCBA (South African National Canary Breeders Association).

    I’ve recently taken on breeding canaries of the Agate group. Four years into the breeding programe I have been able to narrow the colours to monomorhic (pastels) and dimorphic colour variation. Last year I reached my longterm goal of having pure Agate pairs that would produce 9/10 of their breed. However something went wrong in the colour of two young birds from the same nest. The parents are an intensive blue agate and an intensive green ivory agate that are non related produce an intensive blue male with a single white middle toe as opposed to normally black feet and a hen which was green ivory pastel in colour but through the moult and as she reaches maturity has developed white or slightly opaque feathers on her head and back with no change to the flight feathers, tail feathers or breast feathers remain green ivory. I am no expert but think that these two birds from the same nest have a visual progressive colour gene mutation in the female and a non visual but split mutation in the male (as seen in the single white toe).

    Is it possible that they may have vitiligo. How can I be sure. Are their any theoretical trials that I can use to confirm this provisional diagnosis?

    Ia there a way to breed this colour mutation consistantly?

    I am excited and optomistic about the forthcoming breeding season as both these birds have reached maturity.

    Eagerely awaiting your response.

    AM Badrudin.

    Reply
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