Ring-necked Duck - Aythya collaris

This year we've been fortunate to view greater than average numbers of Ring-necked Ducks,Aythya collaris. At Las Gallinas in November we watched a raft of up to 100 Ring-necks, swimming and foraging as a pretty close group, but seemingly not paired up. Similarly, in early December at the Sacramento NWR we counted a flock of over 400 unpaired Ring-necks in the pond near the viewing platform. Since then numbers have declined at both locations, for whatever reason(s). Perhaps the drought has played a role, but water levels seemed about the same at these managed areas.

Fast forward to January 30, where we watched a few Ring-necked ducks on Jan 30, close to the viewing platform on the auto route at Sac NWR. The pair shown here appeared to have formed a bond, as they rested quietly.

Pair formation in Anatidae, the Duck Family, is variable. The Geese and Swans are known to mate for life, whereas most the the usual duck species we see here (dabbling and diving ducks) are seasonally monogamous, forming the pair bond on the wintering grounds or during migration. The Ring-necked Ducks are thought to form pairs during migration, which for them means March and April, as they head to subarctic breeding areas across Canada and the the northern U. S.  Perhaps this paired were simply hanging out as birds of a feather, rather than a bonded pair, but they did not drift apart in the period we watched.

Good article on waterfowl breeding:http://www.ducks.org/conservation/waterfowl-biology/waterfowl-mating-systems/

Overcast afternoon light is usually bad for birds with bright coloration or complex plumage, but it works nicely for species that have a lot of black and white. 

The identification of the male Ring-necked Duck is pretty straightforward if you can see the bill, with the prominent white outline where the bill joins the face. When the bill is tucked it's still pretty straightforward, as there are only 2 diving ducks (Aythya species) with black backs, and the grayflank with the upward white spur at the shoulder is distinctive for the Ring-necked male. The uncommon Tufted Duck, Aythya fuligula, is the other black-backed diving duck, but the male has a bright white flank and a less prominent spur at the shoulder. So when viewing a large flock of diving ducks, say at an area like Lake Merritt in Oakland, check for ducks with black backs, and then check their flanks to see if gray or white.

Here's a shot of a Tufted Ducks taken at Aquatic Park, Berkeley about 6 years ago.

Note the very white flank and the lack of a white ring on the bill. Oh, and the tuft!

And here's one from Lake Merritt, Oakland. Can't see the tuft well, but note the white flank and the lack of a white ring on the bill.