Lesser Scaup Summer Plumage Transition

By Bobby Brown

One interesting thing about having unusual species spend a summer at a location is that you can track an individual bird, since it's the only one of its species present. Rose Valley Lake is a great location for that to happen with ducks. This is a case study of the plumage transition of a male Lesser Scaup during May through September 2020. Of course, we can't be absolutely certain it is the same bird, but it's the most likely scenario.

May

The bird started to seem like he was going to stay for the summer when he was present in late May. At that point, he was still in breeding plumage.

May 22, 2020

June

In early June, the bird was still mostly white in the flanks.

June 7, 2020

By later in the month, brown started appearing in the flanks.

June 21, 2020

July

The bird was not seen for a few weeks, but then was seen again in mid-July, with noticeably browner flanks. It's possible that the bird was "lying low" while molting his flight feathers, which is why he wasn't seen.