BIRDING BY HINDSIGHT: A Second Look at Ducks
If ever there were an unassuming group of birds, one that attracts relatively little attention from birding experts or identification articles, this would be it. If you’re a hunter or wildlife refuge manager, sure, ducks and other waterfowl are of great import, but to many birders they tend to be taken pretty much for granted. The males, at least, usually just sleep or swim there in our spotting scope’s field of view as we match their generally unambiguous patterns with the pictures in the field guides. And if one of those nondescript females drifts into view, most of the time there’s a male of the same species next to her which is a lot easier to figure out.
Hawks...shorebirds...gulls...flycatchers... confusing fall warblers...sparrows — now here we have some real birds to worry about and argue over. It’s these that get all the publicity, not those perfectly obvious Wood Ducks and their ilk.
Still, I often see birders struggling with the identifications of some ducks that I would consider straightforward. And there are apparently enough difficulties to necessitate an identification reference devoted to ducks and other waterfowl, namely: Waterfowl: An Identification Guide to the Ducks, Geese and Swans of the World by Madge and Burn. This book is recommended to anyone trying to solve the more difficult identifications which are beyond the scope of this article or your Geographic field guide.
Note, however, duck difficulties are relatively few in number. It is also necessary to pay attention when examining the color plates of Waterfowl, since the arrangement of the species is frustrating and confusing. In most cases, the placement of a species’ illustrations inexplicably does not match the placement of that species’ text and range maps on the facing page!
Following are some brief comments on the identification of those ducks which may pose difficulties for Minnesota birders. Most of these involve female-plumaged birds at rest, since ducks are more easily identified when their wing patterns are visible. In most cases here, "female-plumaged" also applies to full-grown immatures in late summer and fall, adult males in eclipse plumage in summer and early fall, and adult females at any season.
Teals with Green Wings
Sometimes swimming female ducks do us a favor by arranging their folded wings in such a way that their wing patches become visible. So, if you’re looking at a dabbling duck small enough to convince you it’s one of the teals, and a piece of a green becomes visible on the folded wing, are you safe in assuming it’s a Green-winged? Sorry, it’s not that simple, since Blue-wingeds (and Cinnamons, for that matter) also have a green secondary patch in addition to their blue wing coverts.
With practice or direct comparison, you’ll also see female Green-wingeds appear darker overall than Blue-wingeds, with a smaller bill and a steeper forehead profile. More difficult is the separation of female-plumaged Blue-winged and Cinnamon teals. Given a good look or direct comparison, though, Cinnamons appear richer brown overall, with a plainer face pattern and a larger bill; Blue-wingeds are more grayish brown, with a more obvious line through the eye and a pale spot at the base of a smaller bill.
Nondescript male Cinnamons in eclipse plumage during summer and early fall offer an additional clue if you’re close enough: their eyes are red. The real problem is with immature teals in fall of both sexes and all three species, since those plumage differences mentioned above do not apply. When faced with a teal you’re not sure of, consult Madge and Burn’s Waterfowl guide, and it is also worth finding and reading the article on teal identification in Birding magazine (23:124–133).
[Author's Note, February 2016 – As pointed out in The Sibley Guide to Birds, a good mark on female-plumaged Green-wingeds is the buff or white horizonal bar on the side of the tail; however, this feature is often less conspicuous than shown by Sibley and may be concealed by other feathers.]
If ever there were a duck birders take for granted and spend little time examining with a critical eye, it would be the ubiquitous Mallard. Still, a female-plumaged Mallard is quite nondescript if its diagnostic wing pattern is not visible, its plumage is as featureless as that of a female teal, and birders frequently have trouble distinguishing between a teal and Mallard when size is unclear.
A most frequent and underrated identification problem involves males in eclipse plumage in summer and fall. Before these Mallards regain their full breeding plumage, their chest is dark enough to make their head look contrastingly paler than the rest of their generally brown plumage. The result is that these ducks become misidentified as American Black Ducks.
While female Northern Pintails often give beginning birders problems, this is one duck that should be relatively easy to figure out. The combination of blue-gray bill, long and thin neck, and overall uniformly grayish buff plumage should make a pintail relatively easy to pick out of a flock. In addition, a female-plumaged pintail is just as easy to tell in flight. Not only is its long, thin neck distinctive, but its tail is visibly longer and more pointed than most other ducks.
I say “most” because birders are generally unaware that the tail of an American Wigeon also appears visibly pointed and quite pintail-like in flight. But this wigeon-pintail resemblance ends when a female-plumaged wigeon is viewed at rest. It’s actually as distinctive in appearance as the pintail: it also has a bluish gray bill, but note the wigeon’s unique pattern of grayish head contrasting with buffy brown sides.
And speaking of wigeons, how does one identify a female Eurasian Wigeon, and what about the problem of Eurasian x American hybrids? Good questions, for which there are no good answers possible within the space limitations of this article. Most female Eurasians have richer brown heads than the gray-headed female Americans, but some Eurasian Wigeons have grayer heads and would be identifiable only if their gray axillaries are visible in flight (white axillaries on Americans). It would be best to consult Madge and Burn’s book for more information on these females.
The issue of hybrid wigeons, males included, is even more complex. A short article in Birding magazine (28:309–310) discusses this problem in general and refers the reader to a more specific article on these hybrids in the journal Western Birds (24:105–107). Read them both and let me know what you learn, since I have no idea how to tell a hybrid from the real thing.
As indicated earlier, the plumages of female teals and Mallards are best described as nondescript. Now add female-plumaged Gadwall to this list, since it looks a lot like a female Mallard when wing patterns are not visible. Note, however, the Gadwall’s bill is evenly bicolored: dark gray on the top half, orange on the lower half. A female Mallard’s bill is also dark gray and orange, but the line dividing these colors tends not to be as straight. Look also for the Gadwall’s steeper forehead profile (more sloping on the Mallard) and its fainter eye line which often disappears in front of the eye (the Mallard’s eye line is bolder).
All the field guides correctly point out the difference in the head-bill profiles of Canvasbacks and Redheads. But too many birders are unaware that the plumages of these two ducks — whether male or female — is usually easier to see. If it’s a male, note the Canvasback’s bright white back and sides, which are quite unlike the dingy gray back and sides of the Redhead. The females are almost as distinctive, with the Canvasback having a buffy head/neck and pale gray back/sides, unlike the Redhead which is darker and more uniform brown overall.
Redheads vs. Ring-neckeds
So, if a female-plumaged Redhead fails to resemble a Canvasback, how does it differ from a female-plumaged Ring-necked Duck? A good question, and one that is not asked often enough. I have yet to find a field guide which considers them similar species, and not too many years ago I was still not entirely sure how to separate these two females.
The guides do note the Ring-necked’s white ring near the bill tip, its eye ring, and its white line behind the eye, but they fail to mention that some Redheads have similar features. The useful differences are two-fold. First, note the Redhead’s rounder head profile, unlike the Ring-necked’s clearly peaked head shape. Second, the Redhead’s overall plumage is more uniform brown, while the Ring-necked’s plumage is two-toned with its crown, hindneck, and back darker than its face, foreneck, and sides.
The difficulties of Lesser vs. Greater Scaup identification have long been a topic of discussion among birders and in the field guides. Field marks such as the male’s iridescent head colors (which are unreliable and dependent on light conditions), wing stripe lengths (often hard to clearly see and frequently intermediate), and head shapes (now we’re getting somewhere) are all familiar enough that they need not be repeated here. Instead, in addition to the Madge and Burn guide, I would refer the reader to the chapter on scaup in Kaufman’s Advanced Birding guide for further information.
My only comments here are three-fold. First, note that some female scaup – Greaters more than Lessers? – show an obvious white spot on the ear coverts as the breeding season approaches. Be aware that such scaup might be mistaken for female-plumaged Surf or White-winged scoters.
Second, while comparative head shape is perhaps the most useful scaup field mark of all, be aware that actively diving Lessers often appear as round- or flat-headed as any Greater. Greaters always seem consistent in their rounder head profiles, but I see Lessers all the time with what seem to be intermediate head shapes — or a shape that appears to alternate between peaked and round.
This leads me to point number three: I seem to be getting worse, not better, at scaup identification. The more I have been looking at scaup in recent years, the less confident I seem to be about their identity. It’s that head shape problem that seems to be most troubling, something that never apparently confused me in the past. You’re certainly not alone, therefore, if scaup identification is something you have yet to feel comfortable with.
Just finding an eider in Minnesota is hard enough, and once you do things don’t get any easier as you try to identify it. While adult males are no problem, it is most likely you’ll encounter a female-plumaged bird or a young male. Most King Eiders (the more likely of the two eiders possible in Minnesota) have a white eye ring and stripe behind the eye, which most Commons lack. On female Kings, try to see the shorter, V-shaped barring on the sides; female Commons have longer, straighter lines on their sides.
With first-year males (which are highly variable in plumage) and females, concentrate especially on the feathering at the base of the bill: rounder in shape and stopping short of the nostril on Kings; more pointed in shape and extending up to the nostril on Commons. Once again, for more information consult the Madge and Burn Waterfowl guide.
Contrary to most field guide illustrations, female-plumaged Harlequin Ducks usually appear to have two, not three, head spots. That small third spot in front of the eye either tends to be indistinct or it merges with the spot at the base of the bill. As a result, these "two-spotted" Harlequins are frequently mistaken for female scoters when relative size is unclear.
This article has already touched on how female scaup and Harlequin Ducks can be misidentified as scoters, but how does one separate non-adult male scoters from each other? Sure, part of the White-winged’s wing patch often pokes out into view on a swimming bird, but it’s amazing how long one of these scoters can swim without offering a glimpse of that white.
Such White-wingeds then look a lot like Surf Scoters, but it’s helpful to look for two features before claiming a genuine Surf Scoter. First, the base of a Surf’s bill meets the face and the first of its pale head spots as a straight vertical line, while the base of the White-winged’s bill is curved. Second, and probably a more useful difference, the Surf’s crown is contrastingly blacker than the rest of the face, while the White-winged lacks this contrast. (But beware: this blacker crown is even visible on a distant Surf Scoter when its head spots may not be evident, and it will then resemble a female-plumaged Black Scoter.)
Female-plumaged goldeneye identification is indeed one of those few problems with ducks that cannot be adequately covered in an article such as this. Of course, Madge and Burn’s guide is recommended, and it would also be helpful to consult the article on goldeneyes in Birding magazine from a few years ago (18:17–27).
While space limitations preclude discussion here of the finer points of goldeneye identification, there are four points to be aware of when addressing this problem. First, contrary to what that Birding article implies, there is no useful difference between the two goldeneyes in the amount of white visible in the folded wings of a swimming bird: this depends entirely on how the duck chooses to arrange its feathers.
Second, beware of bill colors, since female Commons infrequently appear to have entirely yellow or orange bills. And, contrary to that Birding article, all adult female Barrow’s have yellow or orange bills. A goldeneye with a bicolored bill is most likely a Common, and would probably only be a Barrow’s if in transition between juvenile and adult plumages or if an adult female of the non-migratory Iceland population (see Birding 19:21–22).
Third, immature goldeneyes are not golden-eyed. They have duller, browner eyes, and, more importantly, they may not yet have developed the “correct” head profile and bill shape of an adult. Therefore, while an adult female goldeneye’s head/bill profile is important, do not rely on it when looking at a brown-eyed immature.
Finally, female-plumaged Barrow’s may tend to have darker brown heads than Commons, but this is often tricky to determine depending on light conditions. Also note that in strong light a female Common’s head clearly appears reddish brown, which, in combination with its grayish body, has misled more than one beginner into mistaking it for a male Redhead.
It was only a few years ago I began to notice something about Buffleheads and Hooded Mergansers that had somehow escaped me before then. This revelation was that first-year males of both these species, especially in spring, are generally dark overall with a white patch on the side of the head. In other words, they both look like adult female Buffleheads. While one of these young male Buffleheads is not much of a problem (no harm done if you mistake it for an adult female), but be aware of the potential for misidentifying a young male Hooded Merganser as a female-plumaged Bufflehead.
The standard field guides have always been adequate in showing the difference between female Common and Red-breasted mergansers. A Common shows an obvious and clean-cut contrast between its reddish brown head and its white throat and chest, while these colors are blurred on a Red-breasted.
There is a problem, though, with immature Commons in summer and fall which have less distinct head-throad-chest patterns and look very much like female Red-breasteds. When faced with such an ambiguous merganser, concentrate on its forehead profile (sloping on Common; more vertical on Red-breasted) and its bill shape (thicker at the base on Common; more uniform throughout its length on Red-breasted).
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Now is as good a time as any to concentrate on your duck identification abilities, since fall is winding down (a favorable time to encounter rarities) and Christmas Bird Count time will be here before you know it. A late-lingering duck you encounter now might well be a lone female without any males around to help you figure out her identity. But at any time of year, by all means, there is no better way to reinforce your skill at identifying females than by noting and identifying the males they associate with.
Don’t assume, however, that a female hanging around a male will necessarily be of the same species. For example, male Cinnamon Teals in Minnesota are often attracted to female Blue-wingeds, and male Barrow’s Goldeneyes will similarly associate with female Commons. These lonely males are out of range, they probably can’t find a female of the same species, and out of desperation they end up doing what many birders do – i.e., misidentify a female duck!