All The Ducks!
On a recent birding trip to Merced National Wildlife Refuge, I tallied up a list of sixteen different species of ducks. Only a few more species, around twenty in total, are expected in the Central Valley of California's freshwater marshes during the winter, so I consider that to be an excellent day for ducks!
North American ducks are broadly separated into two categories, largely based on their methods of foraging for food.
Dabbling ducks, also known as "puddle ducks," tend to frequent shallow water, where they are commonly seen tipping bottoms-up to feed on plant matter and invertebrates in the water and on the muddy bottom. They are most at home in water, but walk easily on land as well, as their legs are positioned near the center of their bodies. The wings of dabbling ducks are relatively large, which allows them to take off from the surface of the water, straight up into their air. Dabbling ducks almost all nest on the ground, near water.
Diving ducks are at home in deeper water, where they dive several feet beneath the surface, submerging completely with a forward leap into the water, to forage for invertebrate prey on the lakebed. Their legs are positioned far back on their bodies, giving them excellent underwater propulsion, but making it awkward for them to walk on land. The smaller wings of diving ducks require that they take a running start across the surface of the water in order to gain enough speed for lift off. Diving ducks tend to nest on platforms of floating vegetation, or in tree cavities.
Many species of ducks, especially dabblers, that spend the winter in California breed up north in the Prairie Potholes, a region that covers parts of the northern midwestern states and Canadian provinces. This mosaic of grasslands and wetlands is one of the most important ecosystems for nesting ducks in North America. Learn more about the Prairie Pothole region here.
And now, here they all are: Twenty ducks found in California's Great Central Valley, presented here in all their glorious dabbling and diving diversity.
Dabbling Ducks
As a general rule, these are the ducks that show up in large winter flocks in wetlands of California's Central Valley.
Wood Duck
Though first in my list of dabblers, Wood Ducks are technically "perching ducks." They are very unlike other dabbling ducks and never show up in large flocks anywhere! Easily our flashiest duck, the Wood Duck is entirely unique in North America; its closest relative is the Mandarin Duck of Asia. As its name suggests, Wood Ducks live in bodies of water that are heavily wooded, like swamps and riparian areas, where they nest in tree cavities and manmade nest boxes. In my experience, Wood Ducks are secretive, flighty and difficult to get very close to.
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| Male Wood Duck. The female is muted brown in color, with a teardrop-shaped white eyering. |
Mallard
Our most common and familiar duck, the emerald-headed Mallard is equally at home in city parks and wilderness wetlands. Most breeds of domestic duck have been developed from the Mallard, and wild Mallards and their domestic counterparts interbreed freely when given the chance; an aberrantly colored "mallard" is probably one of these domestic offshoots or hybrids.
Learn more about Mallards, as well as duck physiology and behavior, in this article.
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| Male and female (left) Mallard |
Gadwall
Unlike most males in the duck world, the male Gadwall is nearly as subdued in color as the female. But look closely: The brown of the male Gadwall is shaded and patterned with exquisite detail, and off-set by just the smallest, most elegant touches of black and white.
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| Male and female (left) Gadwall |
Northern Pintail
Arguably our most elegant duck, Northern Pintails have distinct silhouettes on the water as well as in flight: long, thin necks in front and long, pointed tails behind. A thin stripe up each side of the chocolate-colored necks of the male only adds to their grace, and in good light, the "plain" brown head takes on a lustrous, iridescent greenish sheen.
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| Male and female (front) Northern Pintail |
American Wigeon
In good light, the bright white forehead patch and iridescent green thumbprint smudge around and behind the eye of the American Wigeon is diagnostic, while the small, almost stubby-looking bill can be a helpful identifying feature in poor light. In flight, American Wigeons show large white oval patches on their wings. But perhaps my favorite identifying feature of the American Wigeon is its sound: a distinct three-syllable whistling that I think sounds a little like a squeaky toy or a kazoo. (Listen here.)
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| Male and female (back) American Wigeon |
Eurasian Wigeon
The Old World cousin of the American Wigeon, Eurasian Wigeons show up in small numbers each winter, associating with flocks of wigeons and other dabbling ducks. A Eurasian Wigeon is always a treat to find, and males are easily distinguishable by their cinnamon-red head and gray body; females look very similar to female American Wigeons.
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| Male Eurasian Wigeon |
Blue-winged Teal
Less abundant than the other dabbling ducks and never, in my experience, found in large numbers in the Central Valley, Blue-winged Teals are one of the most highly sought-after of the dabblers. The white crescent-moon on the steely blue-gray face of the male is typically what grabs the eye first, but don't miss the intricate patterns and subtle shadings of the body feathers as well! Females show a faint hint of white crescent, but are much more subdued than the males in color. The large blue wing patch is best seen in flight.
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| Male and female (back) Blue-winged Teal |
Cinnamon Teal
There is no other North American duck colored as richly as the Cinnamon Teal, with its ruby-red eyes, ebony black bill, deep cinnamon-colored body, and gold-streaked scapulars and tertials (the feathers more or less on its back). Restricted to the western United States, this special duck is a target bird for many visiting birders, and those of us in the west never get tired of seeing it either!
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| Cinnamon Teal males and female (center) |
Northern Shoveler
The Northern Shoveler, with its characteristically large bill, is one of our most common and numerous dabbling ducks, often occurring in flocks of hundreds or thousands of birds in shallow wetland areas. Though females are nondescript in color, they can be readily identified by their large, broad, spoon- or shovel-shaped bill, which they use to filter seeds and invertebrates from the water.
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| Northern Shoveler males and females (with their heads tucked) |
Green-winged Teal
Our smallest dabbling duck, Green-winged Teals often gather in large flocks. When spooked, flocks of these little ducks take to the air in one body, maneuvering acrobatically through the air in a style that, from a distance, is surprisingly similar in appearance to that of a flock of sandpipers in flight. The male's whistled "peep" call is a good indication that a flock of Green-winged Teal is in the area. And while the females are fairly nondescript, their small size and delicate proportions are a clue to their identity.
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| Male Green-winged Teal |
Diving Ducks
Typically, diving ducks don't gather in large flocks in Central Valley wetlands, and are more likely to be encountered in large numbers on deeper bodies of water, like reservoirs and coastal bays.
Canvasback
Named for its bright whiteish back, the distinct silhouette and dashing colors of the Canvasback make it easy to spot. Even from a distance, the sloping forehead stands out in a crowd, and this feature makes even the more cryptically-colored female easy to identify. In Central Valley wetlands, Canvasbacks are usually found in small numbers, while larger flocks gather at deeper water overwintering sites around the San Francisco Bay.
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| Canvasback males with female (center) |
Redhead
Like Canvasbacks, Redheads never appear in Central Valley wetlands in large numbers, and picking one or two out of a distant flock of ducks is always a fun surprise. While colored similarly to the Canvasback, the two species have very different and distinct silhouettes. Additionally, in good light, the male Redhead's blue bill and golden eye stand out prominently, while the Canvasback's black bill and red eye often blend into their darkly colored heads.
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| Distant male Redhead with Green-winged Teal |
Ring-necked Duck
Perhaps a more descriptive name for this duck would be "Ring-billed Duck," since the chestnut-colored ring around their dark necks is not usually visible in the field. Look for the white ring on the gray and black bill instead, and note the black back of the Ring-necked Duck to distinguish it at a distance from similarly-colored scaups. Also notice the distinctly peaked shape of this species' head, which is often visible from a great distance and a helpful diagnostic feature. In good light, look for the breeding male's chestnut neck ring on individuals in flight with necks outstretched, but don't count on it to clinch an ID!
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| Ring-necked Duck male and female (right) |
Lesser Scaup
Similar in color scheme to the Ring-necked Duck, but with a lighter-colored back and less-flashy bill, the Lesser Scaup is the likelier of the two scaup species to be found on freshwater wetlands and reservoirs of the Central Valley. Distinguishing between the Lesser and Greater Scaup can be challenging, and is usually a matter of analyzing head shape: Lesser Scaup has a taller, more peaked head, while the head of the Greater Scaup is more rounded. Other subtle differences in bill and head color are even more tricky to discern and less reliable.
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| Lesser Scaup male and female (right) |
Greater Scaup
The Greater Scaup is far less common in the Central Valley than the Lesser Scaup, and is much more likely to be seen along the coast of California on larger bodies of water, especially saltwater bays.
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| Greater Scaup male |
Common Goldeneye
Named for pale gold-colored eyes that stand out strikingly against the male's dark green head as well as the female's light brown head, Common Goldeneyes certainly are beautiful ducks. (It's unfortunate that I don't have a better photograph of one!) Like other diving ducks, goldeneyes prefer larger bodies of water and are commonly seen on rivers as well. Common Goldeneyes breed in the boreal forests of Canada and Alaska, where they nest in tree cavities. Very rarely a Barrow's Goldeneye will turn up in the Central Valley, mixed in with a flock of Common Goldeneyes, but they are more likely to be seen around the San Francisco Bay and, interestingly, along the American River in Sacramento.
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| Common Goldeneye male (center) and female (behind the male) with a flock of mostly female Bufflehead |
Bufflehead
Definitely a contender for our cutest species of duck, the diminutive Bufflehead is also North America's smallest duck. This quintessentially rubber ducky-shaped duck is an active diver, frequently disappearing completely under the surface of the water only to reappear some distance away. Often, entire flocks dive together! Males are striking black and white from a distance, but in good light, their heads show brilliant green and purple iridescence. Females (pictured above) are less dramatically colored but no less adorable. Bufflehead nest in tree cavities made by woodpeckers in the boreal forests of Alaska and Canada, and some also breed in suitable habitat in the Rocky Mountains, Cascades and northern Sierra Nevada.
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| Male Bufflehead |
Hooded Merganser
Two species of mergansers (fish-eating ducks with unusually thin, serrated bills) are regularly seen in the Central Valley, and the Hooded Merganser is the less-common of the two. In the summer, they nest in tree cavities near wooded ponds and streams in the northwestern and eastern U.S., and in the winter they seem to favor similar partially wooded habitat. (In my experience, they are usually both secretive and flighty.) The keys to identifying these nifty little ducks are their thin bill and extravagant crest, which can be raised and lowered in both sexes to dramatically alter the silhouette of the bird.
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| Creeping up on distant Hooded Merganser male (left) and females (right) |
Common Merganser
Slightly more common in winter than the Hooded Merganser, Common Mergansers favor streams and larger bodies of water. In the summer, they nest in tree cavities along wooded lakes and rivers in northern forests. Look for the male's dazzling forest-green head and red bill; females have a cinnamon-colored head with a shaggy crest and prominent white chin patch. Watch as hunting mergansers put their heads underwater to look for fish below the surface, like a kid playing with a new pair of goggles in the pool!
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| Male Common Merganser |
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| Female Common Merganser |
Ruddy Duck
The small yet stocky Ruddy Duck is another classically cute rubber ducky-shaped duck. In winter, they are somewhat drab in color, though the white cheek patch of the male is a good field mark to look for. Come spring, male Ruddies transform into gorgeous rufous-red ducks with black heads and incredible oversized sky-blue bills. As our only "stiff tailed" duck, Ruddy Ducks have a distinct silhouette: their somewhat long, fan-shaped tails are held stiffly upright, or straight out in the water. Check out this article for more on Ruddy Ducks.
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| Winter (nonbreeding) male Ruddy Ducks, just beginning to develop their amazing bright blue bills for spring |
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| Male Ruddy Duck, looking his best in spring |
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