Aythya valisineria
The Canvasback (Aythya valisineria), so called because of its bright white back, is a diving duck which breeds across much of the United States and Canada. The species winters in the southern U.S. and Mexico. The first 2 shots on this page show a male Canvasback which was wintering in Tucson, Pima Co., Arizona, in March, 2009. These images were taken with a Canon EOS 1D Mark III and EF 70-200mm F/2.8 L IS lens and 2X extender.
The next 2 shots of a female Canvasback were taken in January, 2010, in Austin, Travis Co., Texas, with a Canon EOS 1D Mark III and an EF 800mm F/5.6 L IS lens and 1.4X extender.