Lesser Later

Scaup, probably Lesser Scaup (Aythya affinis)

Weeks after the thick rafts of earlier Scaup departed (See “Ignored Tailwind,” October 18 2021), a second shift of them arrived here on the North Basin. These mostly organized themselves into two rafts, then three, of about a hundred birds each. Sometimes they scattered, maintaining a social distance of twenty feet or more. At other times they formed dense trains following a lead duck in one direction or another.

Distinguishing Greater Scaup from Lesser is really above my pay grade. Nevertheless, I’m going to hazard a guess that these are Lesser. It’s the steep slope of the foreheads and the resulting more pointy crowns. The Lesser are known as late migrants, both coming and going. But opinions will differ.

In the photo below, the female is on top, with characteristic white patches above the beak. Her back and flanks are darker than the male’s. The males are mostly silent. The females do most of the vocalizing.

These birds do their breeding mostly in the northwest, including Alaska, British Columbia, and inland areas west of the Mississippi. They stay below the Arctic Circle. There are some breeding colonies in Washington, Oregon and northeast California. In late fall, they migrate south in large numbers, descending by the millions on the shores of the Gulf of Mexico. What we see here constitutes a tiny sample. They migrate mostly at night, taking off shortly after sunset. They can fly at around 50 mph.

Scaup prefer a carnivorous diet, feeding on shrimp, clams, mussels and the like. However, the video above shows them feeding on seaweed. They take what they can get.

Scaup, probably Lesser Scaup, female (top) and male, (Aythya affinis)

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