RSPB England’s Oriole Wagstaff looks at the difference between albino birds and leucism, and why blue feathers aren’t always what they seem.
Ever spotted a curious white feathered bird? Maybe it looked familiar but didn’t quite match the colour or markings you’re used to seeing. Watch the birds in your garden, or local green space long enough, and you’ll soon see some with unusually coloured feathers. The chances are you haven’t discovered a new species (sorry, not this time) but you’ve spotted a bird with albinism, leucism or melanism. These are genetic conditions that affect an animal’s colour. Here we reveal how to identify the different conditions and what that means for these unusual animals.
Animals with albinism
Albinism is a genetic mutation where there is a total lack of the pigment melanin. Melanin produces most colours in feathers and can be black, brown, red or yellow. Albino birds can be identified by their red or pink eyes, where the lack of melanin in the eyes allows the blood to be visible. These striking eyes are also combined with white feather colour, pale legs and a pale beak. However, albinos are not always completely white. Carotenoid pigments, which produce red, orange and yellow colours, are often hidden when melanin is present, but stand out in albino birds. So, an albino goldfinch may still have its striking red face and yellow wing stripes.
Albino Squirrel. Photo credit: Sussex Sara
Unfortunately, albino birds tend to be at a disadvantage. They often have poor eyesight and their lack of colour often means they stand out more to predators, making them a pretty rare sight in the wild.
Look out for leucism
Leucism is a genetic condition, meaning it can be passed down from parents, and is far more common in birds than albinism. Leucistic birds have only a partial loss of melanin, which can also lead to white feathers, but, unlike albinism, can cause washed out colouration. Leucistic birds generally have weaker feathers which can challenge a birds’ ability to fly making it also vulnerable to predation. A leucistic bird may look similar to an albino bird but the key identifier is dark, not red, eyes.
Albinism and leucism can also be found in other animals. Albino squirrels were once thought to be incredibly rare, but they may in fact be more common than once thought.
Leucistic pheasant. Photo credit: Sussex Sara
Move over for melanism
Melanistic birds have a higher amount of melanin, generally making animals with this condition appear much darker in colour. They are generally more robust than birds with normal feather colour, as melanin can strengthen feathers. As melanism is also passed down from parents if darker feathers provide an advantage, perhaps improving camouflage from predators, than it can become more common in a population. However, melanism can also be caused by high oil content in a bird’s diet.
There’s no such thing as a blue bird
When it comes to blue feathers, it’s a different story. Bird’s cannot produce blue pigments; blue is a structural colour. That means that our eyes see the colour blue because of the way light reflects off the complex structures of the feather. The true colour of many blue feathers is black or brown and can only be seen in very low light. So that vibrant kingfisher or blue tit would appear very dark in low light.
Keep your eyes peeled for these unique creatures, and if you would like to find out more take a look at our unusual colouration of birds webpage: https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/birdwatching/how-to-identify-birds/abnormal-colouration-of-birds/
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