Listen up! There is a lot of information in this post. I'm sure there have been dissertations galore about black and white diving ducks, and I am going to try to cover it off in one post. Well, it is all relative to how much one knows. One post is all I can muster.
Four Bay Ducks commonly frequent the ponds and bays of Newfoundland. The least often, but regularly spotted, is the Ring-necked Duck. When seen up close, this species (both male and female) is very easy to identify by the white ring that crosses its bill. Other notable features are also helpful: The female has a dark eye surrounded by a white eye ring. This is different from the yellow-eyed scaup and Tufted Ducks. The male also has a white vertical mark behind the black breast and before the wing.
While the record-keepers at e-bird designate the Tufted Duck as being rare in Newfoundland, those of us in St. John's can see them on any and every day of the winter. A flock of a dozen or more moves around the inner-city ponds, making them easily accessible.
When in doubt about the species, check out the head. The tuft on the male and female Tufted Ducks is very obvious, especially on a windy day. The female Tufted does not always have white/rust at the base of the bill. They can be all brown, and in fact, appear to be a darker brown than the female scaup.
The male Greater Scaup and male Lesser Scaup can be tricky to differentiate. I have collected a few shots of both species, mainly to educate myself as well as share the information. The male Greater is often whiter than the lesser. It typically has a green head rather than a purple, although this feature can sometimes not be a reliable field mark to tell the two apart. The Greater has a rounder head, wider beak with a large black nail at the tip.
The female is much more difficult to identify. Like the male, the head is quite round, the beak is wider than the lesser and also has a large black tip. When watching the scaup this week at Mundy (Windy) Pond, I found it helps to be able to view both species together to actually see the differences.
The male Lesser Scaup has a more peaked head, the bill appears more blue and the head is often purple. The beak is more tapered and has a smaller nail.
The female Lesser Scaup often has a cleaner white patch near the base of the bill. As these pictures illustrate, that is not always the case. However, the head is much more peaked than the Greater, and the picture on the right of the grouping shows the tapered, rather than wide, bill. It helps to see the birds paired off, because the female lesser tends to stay with the male lesser...duh!
So, that brings us to the point that actually prompted me to work on this post. I saw two bay ducks right in the center of Forest Pond a while back. I looked and looked but from the distance, I couldn't be sure what I was seeing. At first, I considered Ring-necked, but then changed my mind and thought they were probably Tufted Ducks. It turned out they will Ring-necked. Why couldn't I be sure? I told one of the experienced birders in town about my confusion, and this is what she advised me when trying to identify black and white birds from a distance: Look at the color of the back. Tufted and Ring-necked Ducks have a black back. Check the white vertical line before the wing. A large vertical white line denotes Ring-necked. The scaup have a gray back, and it is almost impossible to distinguish one from the other when far away. This info, by the way, was passed on to my source from another birder. So hoping that I got it right, pass it on!
Now, having shared all of these pictures with a little information, which scaup is this? Its head appears peaked, its head is green, its bill is wide and the nail is large. The sides appear to be bright white. So, despite the appearance of a peaked head, this is probably a Greater Scaup just getting ready to dive.