As we are getting further into winter duck season, I wanted to mention a few things about scaup ID, specifically on the Fairfield/Bridgeport flock.
Captain's Cove in Bridgeport is a known traditional wintering spot for numbers of Lesser Scaup. The ratio varies year to year and month by month each year, but typically, the majority of scaup at this location are Lesser. Greaters are also present, but in smaller numbers.
eBird makes it easy to report and track numbers of each scaup species, but also gives way to making assumptions about the ratios, a problem, since eBird is in itself a scientific database that obviously strives for accuracy in data. Watching eBird checklists over time, I see a number of reports that do not seem to align with the current generally known distribution of scaup at those times, such as Captain's Cove reports with only Greater or mostly Greater with no detail as to how that conclusion was reached.
Recently at Jennings' Beach, part of the Captain's aythya flock (containing the Tufted) has been present offshore. Having searched through them on multiple different days, I noted that the vast majority of them are Lessers. eBird checklists of this current flock that report mainly (or only) Greater cause conflict in the data, resulting in inaccuracies one way or the other. Please use caution in what numbers of these species you are reporting from Jennings' or Captain's-- make a careful estimate, and if not, enter them as Greater/Lesser Scaup. It's not at all useful to simply enter Greater or Lesser without going through the flock.
Another caution about Jennings' is that we tend to think of flocks of scaup on the Sound itself as mostly Greaters. This is usually true, but this current aythya flock off of Jennings' is an exception.
Scaup identification makes this more challenging. Greg Hanisek has sent detailed posts in the past about their identification.
Also on a (somewhat) unrelated note, there is a female scaup off of Jennings' that nearly completely lacks any white on the face. Its face looks completely brown from a distance. Using additional features is important in identifying the Tufted.