More Are Lesser

Two rafts of Scaup, each numbering in the hundreds of birds, cruised near the center of the North Basin Cove. As far as I could tell, they were Greater Scaup, with a few Bufflehead keeping them company. On the south edge of the cove, near the flooded Virginia Street Extension, swam more Scaup, but a much smaller flock, barely a dozen strong. On close examination, these were the first Scaup I have seen on this body of water that I would positively identify as Lesser, not Greater. It’s that steep vertical forehead and the higher peaked head that mark the most visible difference between otherwise indistinguishable species.

The Cornell bird lab website has these “Cool Facts” about Lesser Scaup:

  • Lesser Scaup chicks don’t waste any time. As soon as their down dries, under the water they go. The little ones are a bit too buoyant to stay down for long, but by the time they are 5 to 7 weeks old, they can dive for up to 25 seconds and swim up to 60 feet underwater.
  • Lesser Scaup spend the winter farther south than any other diving duck in their genus (Aythya)—some go as far south as Central America and the Caribbean.
  • In lakes or wetlands with a lot of tiny crustaceans called amphipods that float about in the water, Lesser Scaup often look like they are doing somersaults or other odd acrobatics as they try to pick off the amphipods that cling to their belly feathers as they swim through the water.
  • Lesser Scaup is the most abundant diving duck in North America, with a global breeding population estimated at 3.8 million.
  • The oldest recorded Lesser Scaup was a male at least 18 years old.

The Wikipedia writers note that when counting Scaup gathered in large numbers, it is generally impossible to distinguish Greater from Lesser, and so the count is for generic Scaup. I find consolation here, as I may very well have misidentified Lesser as Greater in the sizable flocks I’ve seen here over the years.

Interestingly, the two species of Scaup do not seem to hybridize, or at least this is disputed. It would be extremeley difficult to tell the hybrids from either of the parent species. DNA confirmation would be required, and remains absent.

Lesser Scaup male (Aythya affinis)

Links: Cornell Audubon Wikipedia