Monday, May 19, 2014

LEUCISM AND (A RARE WHITE CARDINAL PHOTO BLOG)

Hi Everybody!!
Another 'Rare Happening' at the Bird Sanctuary: A White Cardinal Appears! Most Cardinals are flaming red (the male) or honey brown (female). It is unusual for white (or partially white) birds, but predictable among bird populations. I have shared info below from Wikipedia about the 'Leucism' coloring which is not 'Albinism'. The 'Rare Event' is that humans see the birds, as the largest percentage of people do not even notice birds! Of course, I am trying to change that mistake!!! Your photostudy is of the new white cardinal with a bonus reflection to a few years ago when a white headed cardinal came here. You never know what you are going to see today.
Enjoy!

http://en.wikipedia.org/wiki/Leucism

Leucism

From Wikipedia, the free encyclopedia

Leucism /ˈljuːsɪzəm/^[1] is a condition in animals characterized by reducedpigmentation. Unlike albinism, it is caused by a reduction in all types of skin pigment, not just melanin.

Details[edit]

Leucism (occasionally spelled leukism) is a general term for the phenotyperesulting from defects in pigment cell differentiation and/or migration from theneural crest to skin, hair, or feathers during development. This results in either the entire surface (if all pigment cells fail to develop) or patches of body surface (if only a subset are defective) having a lack of cells capable of making pigment.

Since all pigment cell-types differentiate from the same multipotent precursor cell-type, leucism can cause the reduction in all types of pigment. This is in contrast to albinism, for which leucism is often mistaken. Albinism results in the reduction of melanin production only, though the melanocyte (or melanophore) is still present. Thus in species that have other pigment cell-types, for examplexanthophores, albinos are not entirely white, but instead display a pale yellow colour.

More common than a complete absence of pigment cells is localized or incomplete hypopigmentation, resulting in irregular patches of white on an animal that otherwise has normal colouring and patterning. This partial leucism is known as a "pied" or "piebald" effect; and the ratio of white to normal-coloured skin can vary considerably not only between generations, but between different offspring from the same parents, and even between members of the same litter. This is notable in horses, cows, cats, dogs, the urban crow^[2] and the ball python^[3] but is also found in many other species.

A further difference between albinism and leucism is in eye colour. Due to the lack of melanin production in both the retinal pigmented epithelium (RPE) andiris, albinos typically have red eyes due to the underlying blood vessels showing through. In contrast, most leucistic animals have normally coloured eyes. This is because the melanocytes of the RPE are not derived from the neural crest, instead an outpouching of the neural tube generates the optic cup which, in turn, forms the retina. As these cells are from an independent developmental origin, they are typically unaffected by the genetic cause of leucism.

Genes that, when mutated, can cause leucism include, c-kit,^[4] mitf^[5] and

A leucistic Rock Pigeon. Both the eyes and legs are still of the normal colour.

Example from Google Index: pictures of leucistic birds:

https://www.google.com/search?q=lutino&oq=leutino&aqs=chrome.1.69i57j0l5.7297j0j8&sourceid=chrome&es_sm=93&ie=UTF-8#q=leucistic+bird+pictures

These are more of my birds: