BirderBert wrote:is it an adult or Juvenile?
First off, I think it's great that you're asking this question. Trying to age birds provides a much more challenging aspect once the species identification becomes easier.
Second, the answer to your question is neither. The juvenal plumage of a bird is relatively short-lived in many species. In the case of many songbirds it is only a few weeks long. For Lesser Scaup juveniles are around until about August/September after which time they begin their preformative moult. Once this moult occurs they are no longer juvenile, and would more correctly be labelled "immature". Throughout the winter and spring they gradually begin to look more and more like adults.
Eclipse males can look similar to immatures, but this plumage is typically held during the summer/early fall, before they undergo another moult back into the pattern we most typically think of or see in field guides.
Given the date of your sighting (Feb. 22nd) and plumage characteristics, I believe your bird is an immature male in its first-winter (formative plumage).
Nathan Hentze,
Victoria, BC