Spotty sparrow

[goosey]

This female house sparrow arrived in the garden today. What can have caused the white markings?
Do you think it is just genetic or could shock have turned her feathers white like what can happen with people when their hair turns white after a traumatic experience? On Thursday a sparrow hawk attack left them quivering in the ivy too scared to come out for ages.
I have one sparrow with a totally white tail which has been around for more than a year now but I have never seen one like this before.

[RoyW]

I don't think that the causes of leucism (which is the condition that birds like this with abnormal white feather colouration have) are fully understood.
Unlike true albinos, which are unable to produce any melanin because of a genetic condition, leucistic animals are able to produce normal pigments but the pigments are not deposited properly in some feathers. In many cases there will be some sort of genetic problem, but in other cases damage due to injury, or causes like a lack of the correct nutrients while the feathers were growing have been suggested.

Roy.

[goosey]

Thanks Roy, strange isn't it. Luckily the sparrow doesn't seem to have suffered from what ever has caused this condition, she has grown to adulthood and I believe she has chicks somewhere as she has bee taking food away now for the last 10 days. It will be interesting to see if the chicks also has this condition if she brings them into feed once they fledge.