kdee64
Tree Swallow Iridescence, Nanostructure not Pigment
For most of the recent cloudy, wet Yukon summer, trees swallows appeared dull brown with a white belly. The flashy metallic blue colours of their dorsal feathers are seen only under bright light conditions, viewed from a certain angle, especially in morning light when the sun is low. Colour attributed to 'iridescence', also known as 'thin film interference', is not caused by pigment but the manner and angle in which light strikes special nanostructures in their feathers. Nature is so flippin' amazing!
This one was part of a group of migrating tree swallows on the Yukon River that got caught in a freak mid-May snow storm www.flickr.com/photos/keithmwilliams/5727282051/in/photos.... Seen here sunning himself in the freezing temperatures the following morning, he and a few others allowed me to take photos from close range, unusual for this species. I was wearing camo gear and had been standing still for a quite awhile. They were likely in a state of semi-torpor to conserve energy.
Tree Swallow Iridescence, Nanostructure not Pigment
For most of the recent cloudy, wet Yukon summer, trees swallows appeared dull brown with a white belly. The flashy metallic blue colours of their dorsal feathers are seen only under bright light conditions, viewed from a certain angle, especially in morning light when the sun is low. Colour attributed to 'iridescence', also known as 'thin film interference', is not caused by pigment but the manner and angle in which light strikes special nanostructures in their feathers. Nature is so flippin' amazing!
This one was part of a group of migrating tree swallows on the Yukon River that got caught in a freak mid-May snow storm www.flickr.com/photos/keithmwilliams/5727282051/in/photos.... Seen here sunning himself in the freezing temperatures the following morning, he and a few others allowed me to take photos from close range, unusual for this species. I was wearing camo gear and had been standing still for a quite awhile. They were likely in a state of semi-torpor to conserve energy.