Natural History: The Greater Scaup dives primarily for mollusks and other aquatic invertebrates but also feeds on aquatic plants, especially in freshwater environments. In the winter it can be seen in small to large flocks. It nests in depression in mash grass in the arctic.

General Distribution: In the Presidio, this species can be found in salt and fresh water environments.

Frequency: This animal is commonly seen in the fall, spring and winter; it breeds in the arctic in the summer.

Identifying Characteristics: The males of this species have a black head and chest and white underside. The females have a dark head with a white patch in front of the bill, and a rusty color chest and dusky brown body. The bills are bluish. The head is more smoothly rounded than that of the Lesser Scaup.