In April, GrrlScientist posted a picture of a blue house sparrow seen in April among normal colored birds. She commented on the nature of its mutation.
Passer domesticus, var. blue
Birds and butterflies aren’t blue because of pigment but because of their surface texture of their feathers or scales, so I’m guessing that this is a structural change in the feathers.
It would be very interesting to get the local university to put up a mist net, band their catch, and perhaps pluck a feather or two. I’m curious about the genetics of family members — I wonder if some of the brown ones are heterozygous for blue feathers and how many ordinary sparrows it would take to find out. And will the chicks dig it?
GrrlScientist has a follow-up and more photos from the one who spotted this bird in Sydney, Australia, in April.
Science Notes 
July 8, 2009 at 00:49
http://wherelightmeetsdark.com/index.php?module=wiki&page=ExaminingTheEvidenceForBlueAustralianBirds
July 9, 2009 at 14:00
Thanks for the link! Most interesting.
June 18, 2010 at 11:22
Hello,
I had never seen or heard of the blue sparrow before until a couple of weeks ago. We were sitting in our living room when a bird hit our window.I had my husband go out to make sure it was ok and move it if it wasn’t. He brought in a LIVE blue sparrow. I took some pictures of it and we placed it in the planter out front.
After about 3 hours it flew away. I live in Saskatchewan Canada.
June 18, 2010 at 11:47
This must be a second mutation, because I don’t think sparrows migrate that far.
How lucky that the sparrow didn’t break its neck! Can you post a link to your pictures?
June 22, 2010 at 20:58
Sparrows are everywhere here.
June 22, 2010 at 21:28
You can see 2 photos of Brandine’s sparrow by following the link in the first comment.
June 23, 2010 at 06:00
Thanks Chris ! I didn’t know how to do that.
June 23, 2010 at 21:34
Here’s a direct link: Brandine’s blue sparrow.
I’d like to see the other side of it to see if the colour is symmetrical!