Greater Scaup
Aythya marila
The adult greater scaup is 39–56 cm (15–22 in) long with a 71–84 cm (28–33 in) wingspan and a weight of 726–1,360 g (1.601–2.998 lb). It has a light blue bill with a small black nail on the tip, yellow eyes, and is 20% heavier and 10% longer than the closely related lesser scaup. The male has a dark head with a green to purple sheen, a black breast, a light back, a black tail, and a white underside. The drake or male is larger and has a more rounded head than the female. The drake's belly and flanks are a bright white.
ID text from Wikipedia, CC BY-SA 4.0
Redhead
Aythya americana
The redhead is a pochard, a diving duck specially adapted to foraging underwater. Their legs are placed further back on the body, which makes walking on land difficult. The webbing on their feet is larger than dabbling ducks and their bills are broader to facilitate underwater foraging. In addition, pochards have a lobed hind toe. No pochard has a metallic colored speculum, something that is characteristic of other ducks. Voice: There is little information on redhead vocalizations outside of breeding calls. When the neck is fully extended in the neck-stretching display, males emit a cat-like wheee-oww. Males may also produce a soft coughing call, although this call is less frequent. Females emit a soft errrr note when inciting a male.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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