Mute Swans and Fishtown Docks

The photo is by Chris Burda, part of his Fishtown Docks photo gallery (view slideshow).  The University of Michigan’s Animal Diversity Web’s entry for the Mute Swan (cygnus olor) includes photos and information and begins:

Mute swans are large birds, measuring 144 to 158 cm. The wingspan is 2 to 2.5 meters. The two sexes are alike in appearance, except that males are generally larger than females. The plumage is white. They are best distinguished from North American swans by the knob at the base of the upper bill, and the color of the bill itself, which is orange, with the tip and base colored black. The head and neck may sometimes be stained brown from water and mud containing iron.