Mountain Bluebird from three years ago

This is a photo from way back in my archives. I was lucky enough to be with birding friends at Inglewood Bird Sanctuary on 16 April 2013, when about 10 beautiful Mountain Bluebirds (male and female) were flying over the Bow River and landing on the rocks not too far from where we were standing. They repeated this a number of times. Normally, one has to drive out of the city to see these birds, so it's always a treat to see one within city limits.

In Bluebirds, the blue colour is produced by the structure of the feather - there is no blue pigment. "Tiny air pockets in the barbs of feathers can scatter incoming light, resulting in a specific, non-iridescent color. Blue colors in feathers are almost always produced in this manner. Examples include the blue feathers of Bluebirds, Indigo Buntings, Blue Jay's and Steller's Jays."

www.allaboutbirds.org/guide/Mountain_Bluebird/id

www.jstor.org/discover/pgs/index?id=10.2307/4077277&i...

en.wikipedia.org/wiki/Mountain_Bluebird