The Lutino Gouldian Finch is one mutation that has not been seen in our hobby for some sixty plus years, so I would like to make comments on what science has found after fifteen years studying the Lutino. Making it less difficult in understanding the difference between a Lutino or say, a Recessive Fallow as both have bright red eyes!
Now let’s look at the evidence that scientists have discovered in Lutinos colour mutation genetics, very much explaining how Lutinos feathers and eye color are created. I for one had no idea that there are black eyes as well as red eyes in Lutinos ! Also, credit must be given to those extremely dedicated scientists who spent years studying the lutino mutation in both birds and animals (Van Gouw 1997).
In some circles there is confusion in the literature between Albino and Lutino with the latter being often referred to as partial Albino, which there is no such thing, like being partially pregnant.
There are two types of Melanin present in birds, Eumelanin and Phaeomelanin. Eumelanin is responsible for black, grey, and dark brown feathers. Phaeomelanin is responsible for reddish brown feathers. In a lower concentration of melanin, the colour will appear from yellow brown to almost white. Both melanins together can givecombination colours such as greyish brown! (In the skin and eyes, only eumelanin is present) (Van Gouw 2006).
The Lutino is defined as a partial or total lack of Eumelanin and Phaeomelanin in the feathers because of an inherited disorder of the deposition of pigment in the feathers. Interestingly, in certain forms of Lutino, only feathers become colourless while skin and horny bare parts are normal coloured, including eyes. (Van Gouw 2006)
To explain: Only the pigment of the iris is missing so the iris is clear, the pigment at the back of the eyeball remains present, therefore the eye will look dark.
I do hope I have explained the dark eye satisfactorily, now to explain how the red eye is created.
Lutino’s black and red eyed birds are identical in their feather colour but very different in eye colour, remembering that the black and red eyed birds are developed from the same genetic Lutino family that started from two green birds.
Schizochromism is characterised by the lack of a single pigment from part or all the plumage. It is named after the pigment that is absent. Thus, a non-eumelanin schizochromism bird has no eumelanin black pigment (Harrison 1963) since the skin and eyes contain only eumelanin. Non-eumelanin schizochromism birds have red eyes and pink skin (Van Gouw 2006). The red or pinkish colour of the eyes is caused by the blood that can be seen through the colourless tissue of the eye. This is well known to bird breeders such as budgerigar and canary breeders!
A Lutino, or an unlimited number of other red or black eyed type of Gouldians, is proven by the bird having been born from two green bodied Gouldians (wild type). As to whether it should be called a Lutino depends on how the viewer sees the degree of clear yellow on the back, also the degree of white colouring on the breast and the degree of red or black in the eyes (Martin 1906)
Personally, I would think red eyed birds would have a slightly different colour feather, than the black eyed birds because of lack of eumelanin!
Adieu
Don Crawford
05/05/2024
References:
Potvin, DA and Robinson, RW (2012) Aberrations in plumage colorations in birds. Australian field Ornithology, 29(1), 23 – 30. Guay, PT,
Harrison, C J O. (1963) Non – Melanic, Cartelistic and allied variant plumage in birds. Bulletin of the British Ornithologists Club 83, 90-96.
Milligan. (1904) Albinism – Rhipidura tricolor EMU, (4) 169– 169.
Van Grow H (2006) Not every white bird is an Albino: Sense and Nonsense about color Aberrations in birds. DutchBirding, 28 (2) 79 -89.
Van Grow H (1997) Color genetics of a Ringneck dove, Pigeon Genetics News, View, and Comments. SeptemberPlain City. EUA.