Duck season for me and kick off the series with a visit to Slimbridge to see the fantastic array of wild ducks and a collection of birds around the world allowed to roam free, or simply attracted to the huge wetland reserve. The Canvasback (Aythya valisineria) is the largest of the North American diving ducks, that ranges from between (19–22 in) long and weighs approximately (1.90–3.50 lb), with a wingspan of (31–35 in). The canvasback has a distinctive wedge-shaped head and long graceful neck. The adult male (drake) pictured here, has a black bill, a chestnut red head and neck, a black breast, a greyish back, black rump, and a blackish brown tail. The drake's sides, back, and belly are white with fine vermiculation resembling the weave of a canvas, which gave rise to the bird's common name. The bill is blackish and the legs and feet are bluish-gray. The iris is bright red in the spring, but duller in the winter. The adult female also has a black bill, a light brown head and neck, grading into a darker brown chest and foreback. The sides, flanks, and back are greyish brown. The bill is blackish and the legs and feet are bluish-grey.