The winter of 2005/2006 started out in a rather ordinary way here along the German Baltic sea coast. November had passed, fall migration had basically ceased and everybody - well, maybe not the general public but those who truly matter: the birders - was awaiting the influx of the winter birds from Scandinavia.
Around the end of the month though, things took a sudden and unexpected turn: Redpolls!
Well, Redpolls aren't very special around here. The central/western European form cabaret has recently colonized this part of Germany and breeding pairs are now frequently seen in gardens and cemeteries all over the place. Each winter, small flocks of the northern flammea are also regulars, usually numbering in their 20ies or 30ies and even though you won't see them each day you're outside, they are around. The winter of 2005/06 however saw an influx of Common Redpolls the like I have never experienced up here. Redpolls were everywhere and even though most flocks were below 100 birds, some exceeded 300.
Then it happened: neighbouring countries, like Denmark to the North and Poland to the East started to report relatively high numbers of Arctic Redpolls within these flocks of Commons and once reports came in from the Netherlands to the West, it was clear that we, too were being overrun by Arctics. Problem was: no reports yet.
How could that be?
Arctic Redpolls are a very rare species in Germany. As a matter of fact, they are really rare. In most years there won't be a single acceptable record and every second or third winter might lead to one or two birds being reported and approved of by the records committee. And that's even an optimistic guess. So my optimistic guess was that none were reported from here not because the species had decided to avoid Germany of all the European countries but because people were seeing but not recognizing them.
All of a sudden, I was a man on a mission.
I ordered all the identification articles I was able to find out about and spent hours and hours in front of my laptop searching for and studying pictures of all sorts of Redpolls. Finally, I felt I was ready and I took my theoretical knowledge to the test: I went out in search for Redpolls.
Okay, I'll cut it short to get to the main point of my post: in the following three months, I studied a total of well over 1,000 Redpolls and found no less than a minimum of 6 Arctics, which might be a record number of Artics found by a single observer in one winter in Germany. So it was pretty good fun.
Yet again, though, there was a problem: back then I didn't have a camera and my digiscoping equipment was horrible, so I had no definitive proof of my "claims". Surely I had told other birders of the Arctics but very frequently, these observers would look at the same flocks the day following an Arctic observation by me and not find the bird amongst the commons. Yet again, I felt, they were seeing but not recognizing!
So what is the problem with identifying an Arctic Redpoll?
The problem seems to be that it is so bleaking similar to the Northern flammea form of the Common Redpoll that even when you look at an Arctic amongst a flammea flock, you don't have that certain light bulp moment kicking in.
You see, when you check through one Warbling Vireo after another in search for a Philadelphia, you go through all of the subtle characters on each bird and often have these moments were you think that this particular Warbling somehow looks different and might show traits of a Philadelphia. So you struggle, and check again, and don't really know what to think of it. But the moment you actually find a Philadelphia, it is plain obvious, bam, there it is, clearly a different species and no mistaking it!
This is not the case with the Arctic Redpoll. Identifying an Arctic Redpoll completely relies on checking a few key field marks but even when you have established that a particular bird simply must be an Arctic, it still doesn't feel like a different bird species amongst the Commons, it just looks like a subtly different bird of the same species.
Therefore, preparation is everything.
And this is something Sibley knows (again!) as well. He's written a short - and I hope he'll extend it like he did on the "Great White" Heron - post on the key identification criteria here to get North American birders prepared for the Hoaries or rather Arctics headed their way. And it seems we might also have another Redpoll invasion this winter here along the southern Baltic coast...
First up, though, there's a need to clarify the taxonomy we are talking about here.
Currently, the Redpolls are divided into three species (two for the more conservative taxonomists):
1. Arctic or Hoary Redpoll Carduelis hornemanni, with two subspecies: C. h. hornemanni breeding on Greenland and neighbouring parts of Canada and exilipes, breeding from Northern Europe accross Siberia into Northern North America.
2. Common Redpoll Carduelis flammea, with three subspecies: islandica on Iceland, rostrata on Greenland and flammea from Scandinavia all the way East to Northern North America.
3. Lesser Redpoll Carduelis cabaret (sometimes considered a subspecies of Common Redpoll), no subspecies: central and western Europe.
So when North American and European birders are searching Redpoll flocks for Arctic/Hoary Redpolls, they are looking at the same forms, trying to find Carduelis hornemanni exilipes amongst Carduelis flammea flammea. Well, some East Coast birders in North America might encounter the Greenland forms, but I'll just forget about that for now...
So now, finally, the part of this post that might bring profit in the form of knowledge to my readers, links and hints:
A very nice homepage for those who can read Swedish (not so much different from German or English) is here, with some bits already translated into English.
Once you've familiarized yourself with the basic identification criteria (summarized nicely in Sibley's post), I have found it very useful to study the bird images available on the Internet, especially tarsiger.com and birdpix.nl, with the Arctic Redpoll links being here and here and the Common Redpoll pics being here and here.
As Sibley has pointed out, there are a few key criteria, and after reading up on Redpoll identification and studying a couple' hundred pictures, I came to the following set of three field marks that a Redpoll must show in order to be identified as an Arctic by me:
a) largest undertail covert purely or almost purely white
b) white rump
c) narrow or no streaking on breast and flanks (as if drawn with a very sharp pencil)
Using these criteria, I was sure to miss a few Arctics as not all Arctics show a combination of these three criteria, but considering the rarity of the species in Germany and the high number of records I obtained during the winter of 2005/06, I considered a very conservative approach appropriate.
Most male Arctic Redpolls are quickly found in a flock of Common Redpolls by their paleness and soft pink breast colouration.
Here, however, are a few tricks and pitfalls I encountered using these criteria.
A general problem:
Redpolls are very active and flighty birds and rarely remain still for more than a couple of minutes before taking to the air again. Searching such an active flock of Redpolls for an Arctic by these subtle characters takes a lot of time and quite frequently I would search a flock of no more than 50 or 60 Redpolls for more than an hour before finding an Arctic.
Furthermore, Redpolls are very active birds, and I can only emphesize that what I wrote back then was not a joke:
"You see, the problem was that one field mark could only be seen from below (undertail coverts) while the other one could only be seen from above: the rump.
Now, Redpolls usually were seen feeding somewhere near the ground in high grass or low in bushes until one of the flock got nervous or maybe bored and decided to cause a bit of a stir, so the whole flock flushed and flew around for a few seconds just to settle down at roughly the same spot again. If this happens every minute you have a very hard time checking all these field marks: 30 seconds to find a potential Arctic, 15 seconds to triple check for the one field mark you are able to look at depending on the bird's relative position to you, 15 seconds to wait and hope the bird would turn around so you could check the other key field mark ... Whoops, sorry, 60 seconds are over and the cards get shuffled again.
30 seconds to find a potential Arctic, 15 seconds to triple check for the one field mark you are able to look at etc."
Arctic Redpolls require patience. Lots of cool-blooded patience.
The white undertail coverts:
The white undertail coverts appear to be the most reliable field mark of the Arctic Redpoll. If your bird shows entirely white undertail coverts, it seems that you can safely call it an Arctic/Hoary. Some Arctics, especially females and immatures, might show a thin dark line on the greatest undertail coverts and if the rest of the bird looks like a "classic" Arctic/Hoary, it is still a safe bet. But a strong, dark, arrow- or drop-shaped mark is almost a dead ringer for Common Redpoll.
However, be sure you are looking at the largest, last undertail covert. A Common Redpoll may show no dark pattern (pure white!) on all but the largest, last undertail covert and that can be misleading! This is something to keep in mind.
On most Common Redpolls, the dark tear-mark on the largest undertail covert is rather obvious and can even be seen on this truly horrible digiscopes image of a male.
The white rump is not a very strong field character of the Arctic as quite a few pale - mostly male - Common Redpoll can show a rump that's close to white (mostly very pale pinkish or a light grey-brown). If your candidate shows a white rump, it might very well be an Arctic, but you still have a few more steps to take before making a certain identification. However, if your bird does not show a white rump, it very, very likely is not an Arctic, not even an immature or female bird.
Beware though that Redpolls often fluff up part of their feathers above the folded wing (on the sides of their back), and when seen from the side, this will very much "definitely" look like a white rump.
This can be seen on the two images below. The first image shows a likely Arctic (female/immature type). The rump is white and the "back flanks" above the wing are fluffed up, leading to a complete white V-shape on the bird's lower back.
The following image shows the same bird again on the left, with a Common Redpoll to the right. Note that the Common also shows a lot of White on the back but that the rump itself is grey/brown, hence producing a pattern of two white lines along the sides of the back but not a complete white "V"-pattern. And yes, that stick is a bit unfortunate but you can still see what I mean...
The finely streaked flanks
Arctics mostly show close to no streaks (males) or very few streaks along the upper breast and flanks and these streaks are mostly very thin and sharply defined, as if drawn with a very pointed pencil.
Beware though that some Commons also show reduced streaks and that the streaks on a Common Redpoll can also be quite sharp and well-defined on the breast. The flanks however should always show a more broad, diffuse pattern of stripes.
As Sibley put it so nicely:
And patience, heaps of patience, I may add.