General Description: Greater Scaup (Aythya marila) are small, sexually dimorphic pond ducks. Males have white sides, and otherwise are black with a green iridescence on the head. The bill is bluish and uniform in color (compare with Ring-necked Duck). Females are mottled brown overall with white around the dark bill. In flight, both genders show white on the trailing half of the secondaries (primaries are all black; again, compare with Ring-necked Duck).

Taxonomy: Anseriformes, Anatidae, Anatinae

Favored Habitat: High arctic ponds and marshes during the breeding season, larger bodies of water during migration (mostly in the eastern U.S.), and coastal areas during winter.

Where to Find: Greater Scaup are uncommon or rare around Las Vegas. Don't look for them anywhere, but keep an eye out during migration at Lake Mead, the Henderson Bird Viewing Preserve, the Pahranagat Valley, and the Overton Wildlife Management Area.

Comments: Difficult to tell from Lesser Scaup. Lesser Scaup are more likely to be seen around Las Vegas because they tend to be more inland than Greater Scaup during winter. Lesser Scaup males may show a purple gloss on the head, whereas Greater Scaup show a green gloss. Lesser Scaup have a bit of a peaked head, whereas the head of a Greater Scaup is more rounded.