A strange place to be

On a walk this morning, a friend spotted this Great Horned Owl half way down the bank of the Bow River, by a sewer outflow. We always see owls sitting in trees, so we were puzzled as to why this one was where it was. Everyone came to the agreement that that couldn't be an owl's egg in front of the bird. Too small - yet, I Googled this and read that in fact the egg of a Great Horned Owl isn't very big (just over 2" long, if I remember correctly). I will HAVE to go and check and see if it is still there tomorrow! Anyone have any ideas about this?