Bird Imprints on Glass
May 08, 2012
Birds collide with windows regularly. According to some theories, it is either because the birds do not see the transparent glass or because they see their reflection and attack to defend their territory.
But we know that these traces are left defined by a very fine powder that surrounds the young feathers of many birds to protect them as they grow.
Richard Heeks maintains a Flickr group where he collects all the photos of this phenomenon.