Common Merganser - Mergus merganser

At Lake Solano Park (Putah Creek) we got good views of a Common Merganser pair, Mergus merganser. The late morning like highlighted the green sheen on the black head and neck plumage of the male. In the first photo the resting pair have tucked their impressive red-orange bills, as many birds will do.

The second shot is a crop to show the serrations on the bill edges, which help a bunch on a bird that depends heavily on catching slippery prey like fishes. Note also the thick base  of the bill (compared to the more slender bill of the Red-breasted Merganser), and how the nostril is positioned well towards the midpoint.

In the third shot we get a good view of the green sheen, and how the longer feathers at the rear of the head form regular rows. The extensive white on the flank and breast of the male often dominates the photo, but makes for an easier identification at a distance.

Found this good summary of feather color from the Cornell Lab:  "Color in Birds"

With birding there is "always something new", at least for my eyes. At the Marin Civic Center I watched a mated pair swimming in the middle of the pond. The female assumed a rather striking posture, swimming low in the water with neck outstretched and almost touching the water as she followed the male in a leisurely paddle out and back. 

This display was described by Townsend in 1916, as documented in the Bent series in 1923:

" At last she succumbs to the captivating display and submerges herself so that only a small part of her body with a bit of the crest appear above the water, and she swims slowly beside or after her mate, sometimes even touching him with her bill. Later she remains motionless, flattens herself still more, the crest disappears, and she sinks so that only a line like that made by a board floating on the water is seen. One would never imagine it to be a live duck."

This particular solicitation was not consummated. Common Mergansers have bred only rarely in Marin (D. Shuford, Marin Breeding Bird Atlas).

Here the female is seen following the male, always staying pretty close. 

Nearby on an island there were 3 female Mergansers that had not found a male yet, but posed nicely as they rested.

The Common Merganser is one our largest ducks, the male weighing up to 3.4 pounds. They prefer fresh water, i.e. lakes and rivers and prefer to nest in a tree cavities in northern climes, i.e. Alaska and all across Canada.