I photographed this great blue heron preening itself for several minutes before capturing this shot. It shows feather residue on his beak. The Cornell Lab of Ornithology says, “Great Blue Herons have specialized feathers on their chest that continually grow and fray. The herons comb this “powder down” with a fringed claw on their middle toes, using the down like a washcloth to remove fish slime and other oils from their feathers as they preen. Applying the powder to their underparts protects their feathers against the slime and oils of swamps.” Also interesting: note the many different types of feathers around its head and shoulders, including the cottony tufts below its chin. Taken with the Nikon D4 and 600mm F4 Nikkor with 2x teleconverter.