BIRDING BY HINDSIGHT: A Second Look at Redpolls

There is a redpoll at my feeder right now. It’s a Hoary Redpoll. . .I think!

Paragraph one is a short one, perhaps, but it already illustrates Rule Number One in redpoll identification. Don’t say: “I see a Hoary Redpoll,” or “There’s a Hoary Redpoll.” Instead, it’s almost always a better idea to say something like: “I think I see a Hoary,” or “That one sort of looks like a Hoary,” or “The redpoll on the left looked pale enough to be a Hoary, but it just flew away.” (The last statement is probably your best choice. Wait until the suspected Hoary flies, so you can then either not have to deal with it, or call it a Hoary after it’s gone without fear of contradiction from someone else.)

Separation of Hoary Redpolls from Commons is certainly one of the most challenging ID problems faced by Minnesota birders, at least in the northern half of the state where Hoarys can be expected in small numbers most winters among the Commons. On the average, I would venture to say that Hoarys make up one to two percent of the redpoll population here. However, there have been several times when I’ve scanned through a couple hundred redpolls or more without detecting a single Hoary, and, conversely, I have sometimes seen an “obvious” Hoary Redpoll with only a few Commons around. Years ago, I once studied a group of eight redpolls in the Sax-Zim Bog near Duluth, and all eight were typical Hoarys!

While there are many redpolls that look dark enough to be safely called Commons, there are an awful lot of marginally pale redpolls out there which I feel defy any confident identification. It certainly rivals the problem faced when one tries to distinguish a paler Thayer’s Gull from a darker Iceland Gull. Both problems could be remedied if the scientists would face reality and start lumping, but, given the current fad of splitting almost everything in sight, this prospect seems unlikely. In fact, there is even talk of splitting the two redpolls into three or more separate species!

So, how does one proceed when trying to add Hoary Redpoll to one’s list? After you master Rule Number One, my suggestion is to follow Rule Number Two: Wait. That is, just keep looking at redpolls and simply wait until the inevitable day when you see a redpoll so pale and “frosty" overall that there is no question it’s a Hoary. It may look larger than the Common Redpolls with it; its upperparts will appear more pale gray overall rather than brown; the streaks on its sides will be narrower, shorter, and fewer in number (or perhaps essentially absent altogether); both its rump and under tail coverts will be devoid of any visible streaks; its bill may have a noticeably shorter and stubbier shape; and, if a male, its breast will have only a faint blush of pink.

If, however, you lack the patience for Rule Two and want to plunge forward with all those “in-between” redpolls, one way to start is to find a copy of the December 1995 issue of Birding magazine and read “Identifying Common and Hoary Redpolls in Winter” (27:447–457). But please read the article and study the photos carefully, and don’t expect them to answer all your redpoll ID questions. If anything, they should raise more questions than they answer — at least they did in my case.

To begin with, the first page of the article includes a highlighted paragraph with the following caveat: “Separation of Hoary and Common redpolls in the field is notoriously difficult, but it can be attempted under ideal conditions and at very close range. Identification is complicated by overlap...between the palest Commons and the darkest (female and immature) Hoarys.” Therefore, be prepared to leave as unidentified all those marginally pale individuals you encounter. Most will simply have to be called redpolls, period. And, as with all difficult identifications, identifying redpolls is a matter of using a combination of as many field marks as possible. When a difficult ID is based on only one or two marks to the exclusion of others, a misidentification often results.

The text of the article continues with additional warnings about the difficulties involved. Words like “variation”, “overlap”, “indistinguishable”, “inseparable”, and “bewildering” are used when discussing the plumages of Hoary and Common redpolls. “Not every individual will be field identifiable to race, or even to species,” the reader is reminded. A full-page chart appears to neatly organize the differences between Hoarys and Commons, but like the main text it is liberally sprinkled with qualifiers: e.g., “pattern probably overlapping,” “measurements overlap completely,” “lots of overlap with Common,” “feature is not particularly evident,” “feature may be faint,” “paleness of the head varies,” “feature does not hold for all individuals,” etc. And these patterns, measurements, features, and extents of paleness are allegedly the diagnostic differences between the two redpolls!

In spite of all this variability, the chart attempts to list Hoary Redpoll characteristics in order of their usefulness in the identification process:

1) unstreaked, or narrowly streaked, under tail coverts (which can be hard to determine when fluffed up);

2) usually unstreaked rump (but some have Common-like streaks);

3) usually whitish or grayish ground color on back (but some are browner like the Common), with contrastingly whiter lower back;

4) little or no streaking on sides (streaks usually, but not always, narrower and shorter than on Common);

5) adult male with only a faint pink wash on breast, paler and usually (but not always) less extensive than on male Common;

6) paler hornemanni subspecies larger overall, especially the head (but size of exilipes Hoary subspecies overlaps Common);

7) usually (but not always) shorter and “stubbier” bill profile;

8) often thicker wing bars and whiter patch on folded secondaries;

9) head often (but not always) paler, washed with buff and contrasts more with back color.

Obviously, however, redpoll identification is not a simple nine-step process. For one thing, I would rank points 5 (pink breast on males fainter; the extent of the color remains unreliable) and 7 (stubbier bill) higher in the usefulness scale. No, these features are not present on all Hoary Redpolls, but when present on a redpoll in question they are strongly indicative it’s a Hoary. And I would consider the whiter lower back feature in point 3 and all of points 8 (whiter wing markings) and 9 (paler, buffier head) to be so dubious that they should have been left off the chart entirely.

To illustrate how difficult all this is, several photos by the author are included in the article, but they often contradict — rather than support — the points made in the chart. A photo of a male Hoary shows its pink extending lower on its underparts than on a male Common in another photo, contrary to point 5. The head size of a hornemanni Hoary in one photo clearly looks small to me, not large (see point 6), and the photo with the largest-headed redpoll of them all is of a Common.

The same Hoary appears in two photos: in the first photo its underparts streaks look much less distinct than in the other photo, and in the latter photo the streaks on this Hoary are just as thick as on a Common in another photo (see point 4). One photo of a redpoll with a whiter lower back (see point 3) is of a Common, not a Hoary. And the Common Redpoll in this same photo (along with some Commons in other photos) all show thick white wing bars and bold white markings in the secondaries, contrary to point 8.

By now, it should be evident you’re not necessarily missing any Great Redpoll Revelations if you don’t have this Birding article at hand. You may do just as well by sticking with Rules Number One and Two, as explained earlier. Beyond these, about the only other thoughts I have on the subject are as follows:

• A redpoll always looks paler when perched overhead (when you’re mostly observing its whitish underparts) than it does when on the ground (when its darker upperparts are more visible). Many times I have found myself looking up in a tree at a potential Hoary which turned into a Common after it flew down to the ground.

• When redpolls are perched overhead, however, this is the time to closely study their under tail coverts for the presence or absence of streaking. But be cautious in your examinations. It’s often difficult to distinguish between an actual streak and a shadow or crease in the coverts, and fluffed-up covert feathers may conceal or diminish a Common’s streaking, potentially leading to a misidentification.

• When looking for Hoary Redpolls, the colder the day the better, at least when trying to study rump patterns. Why? On colder days redpolls tend to fluff themselves up more, droop their wings, and thus reveal their rumps.

• Generally, pink-breasted adult male redpolls tend to look paler overall than females (and immatures). Therefore, don’t necessarily jump to conclusions if a paler redpoll appears among some darker ones, especially if it’s a male.

• There may be a difference in call notes and songs, although more study on this is needed. It is possible the Hoary’s call notes are higher-pitched than a Common’s and not as rapid, and its song may also be higher-pitched, slower and more musical.

• And there seems to be a tendency for Hoary Redpolls to prefer more open habitats: i.e., weedy fields and marshes, smaller stands of alders and tamaracks, etc. Certainly Commons are also found in such areas, and I have seen Hoarys in the woods, but if I want to look for a Hoary I usually head for the wide open spaces.

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By the way, as I started writing this article there actually was a redpoll at my feeder. And there it is again...and it really is a Hoary! I think. Sort of. Never mind — it just flew.