Lesser Scaup
Aythya affinis

The Lesser Scaup and the Greater Scaup are difficult to distinguish, even for experienced observers. Head shape is one way to differentiate them, but winter habitat can help too. If seen in favorable light, during the breeding season in alternate plumage, there is a greenish sheen to the Greater Scaups’ head, while the Lesser Scaup’s sheen is purplish. If viewed in profile, the Greater Scaup’s head is rounded at the crown. The Lesser’s (if in an alert pose) is flattened behind the crown. When seen from a distance, such identifiers are difficult to sort out, and often experienced surveyors will list scaup species in their reports. The nail at the end of a duck’s bill is another useful diagnostic feature. You must have the bird in hand for a measurement. The Greater Scaup’s nail is wider. A more general guideline mentioned in the literature to differentiate the two species is that the Greater Scaup is more of a saltwater bird and the Lesser is more of a freshwater bird. However, this rule seems to break down on the Texas Gulf coast, where the Lesser Scaup is present in greater numbers during the non-breeding season.
During southern California winters, we often find Lesser Scaup on our inland lakes, and Greater Scaup in salt water environs, such as San Diego Bay. When I visited Texas, I learned the scaup gathered in large numbers on the saltwater lagunas between the barrier islands and the mainland were Lesser Scaup, and not the Greater Scaup I first assumed. It seems that winter habitat preferences differ between eastern and western scaup populations.
Pair bonds often occur on the winter grounds and last until the hens lay their eggs. Then the males collect in bachelor groups to molt, leaving the hens in charge of child-rearing. Most of these ducks breed in Alaska and western Canada, but others breed in the northern tier of the western states. They spend winters from the Pacific Northwest and mid-Atlantic coasts south through the southern USA, Mexico, and Central America, the West Indies and Caribbean and slightly into northern South America.
Taxonomists regard the Lesser Scaup as monotypic (i.e. there are no subspecies).
While I was winding up my 2005 Alaska adventure, I stopped at Midway Lake in east-central Alaska and met a Lesser Scaup hen with ducklings in tow. It was the only image of this species I collected on the expedition.
12 Photos

Lesser Scaup(Aythya affinis) |
Description: Salton Sea at Poe Road. Imperial County near Westmoreland, California. |
Date Taken: 2015:04:27 15:59 |
Location:
Poe Road |
Camera Information: NIKON D3X, 800 mm, f/10.0, 1/2000 |
File Name: D3X7525-LesserScaup |
© 2015 Jack Daynes, shadeTree-Imaging.com |


Lesser Scaup(Aythya affinis) |
Description: Pair at the Salton Sea at Poe Road. Imperial County near Westmoreland, California 2015-04-27. |
Date Taken: 2015:04:27 16:16 |
Location:
Poe Road |
Camera Information: NIKON D3X, 800 mm, f/10.0, 1/1600 |
File Name: D3X7623-LesserScaup |
© 2015 Jack Daynes, shadeTree-Imaging.com |


Lesser Scaup(Aythya affinis) |
Description: Salton Sea at Poe Road. Imperial County near Westmoreland, California. |
Date Taken: 2015:04:27 16:17 |
Location:
Poe Road |
Camera Information: NIKON D3X, 800 mm, f/10.0, 1/1600 |
File Name: D3X7635-LesserScaup |
© 2015 Jack Daynes, shadeTree-Imaging.com |


Lesser Scaup(Aythya affinis) |
Description: Pair at the Lower Klamath National Wildlife Refuge, south of Klamath Falls Oregon in California 2016-05-05. |
Date Taken: 2016:05:05 18:10 |
Location:
Lower Klamath NWR |
Camera Information: NIKON D7200, 800 mm, f/8.0, 1/400 |
File Name: D721263-LesserScaup |
© 2016 Jack Daynes, shadeTreeImaging.com |


Lesser Scaup(Aythya affinis) |
Description: Family at Midway Lake, East of Tok, Alaska, on the AlCan Highway 2005-07-12. |
Date Taken: 2005:07:12 11:36 |
Location:
Tetlin |
Camera Information: NIKON D2X, 280 mm, f/5.6, 1/350 |
File Name: JCD8314ScaupFamily |
© 2005 Jack Daynes, shadeTreeImaging.com |


Lesser Scaup(Aythya affinis) |
Description: Miramar Lake. San Diego, California. |
Date Taken: 2005:01:15 12:33 |
Location:
Scripps Ranch |
Camera Information: NIKON D1X, 400 mm, f/8.0, 1/800 |
File Name: JCD_2559LesserScaup-M |
© 2005 Jack Daynes, shadeTree Imaging |


Lesser Scaup(Aythya affinis) |
Description: Female at Miramar Lake. San Diego, California. |
Date Taken: 2005:01:15 13:25 |
Location:
Scripps Ranch |
Camera Information: NIKON D1X, 750 mm, f/8.0, 1/400 |
File Name: JCD_2687LesserScaup-F |
© 2005 Jack Daynes, (shadetree-Imaging.com) |


Lesser Scaup(Aythya affinis) |
Description: Female at Miramar Lake. San Diego, California. |
Date Taken: 2005:01:15 13:47 |
Location:
Scripps Ranch |
Camera Information: NIKON D1X, 800 mm, f/8.0, 1/250 |
File Name: JCD_2743LesserScaup-F |
© 2005 Jack Daynes, (shadetree-Imaging.com) |


Lesser Scaup(Aythya affinis) |
Description: Miramar Lake. San Diego, California. |
Date Taken: 2005:01:15 13:50 |
Location:
Scripps Ranch |
Camera Information: NIKON D1X, 800 mm, f/8.0, 1/250 |
File Name: JCD_2767LesserScaup-M |
© 2005 Jack Daynes, shadeTree Imaging |


Lesser Scaup(Aythya affinis) |
Description: Miramar Lake. San Diego, California. |
Date Taken: 2005:01:15 13:58 |
Location:
Scripps Ranch |
Camera Information: NIKON D1X, 800 mm, f/8.0, 1/500 |
File Name: JCD_2811LesserScaup-M |
© 2005 Jack Daynes, (shadetree-Imaging.com) |


Lesser Scaup(Aythya affinis) |
Description: Miramar Lake. San Diego, California. |
Date Taken: 2005:01:15 14:04 |
Location:
Scripps Ranch |
Camera Information: NIKON D1X, 800 mm, f/8.0, 1/750 |
File Name: JCD_2832LesserScaup-M |
© 2005 Jack Daynes, (shadetree-Imaging.com) |


Lesser Scaup(Aythya affinis) |
Description: Tingley Beach Reserve in Albuquerque New Mexico. |
Date Taken: 2016:03:22 12:58 |
Location:
Tingley Beach |
Camera Information: NIKON D7200, 800 mm, f/8.0, 1/1250 |
File Name: D726365-LesserScaup |
© 2016 Jack Daynes, shadeTreeImaging.com |

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