First off, I, personally, am a wee bit skeptical about the specific
status of hoary redpoll! Carduelis hornemanni has two races -
C.h.hornemanni (the race that breeds in Greenland and that is seen as a
vagrant in Europe [where it is called arctic redpoll]) is a beautiful
little snowball of a bird and quite different from common redpoll. What
we in the NE call hoary is usually the exilipes race. Exilipes is a
different challenge, entirely. It is known that it interbreeds with
common in the northern breeding areas and, in my experience, apparent
intergrades appear in our area. I wonder if what we call hoary is
actually just one end of the normal variation in common redpoll.

Anyway, that aside, here are the field marks that I have culled from
lots of different sources. In my opinion (and all of the below is simply
that - not fact), three words of caution are important: (1) common and
hoary redpolls present famously difficult ID problems and should be
treated with caution; (2)given the high degree of variability in both
"species" I think that it is probably not sufficient to just tick off
one or two of the characters listed below and call it a hoary; (3)these
characteristics probably apply most to adult males. Females and
juveniles may overlap greatly with commons and intergrades and I am
skeptical that they can be separated. 

Overall color - much frostier than male, female or juvenile commons. The
ground color on which the streaking is superimposed is rather more
frosty grey, than the more brownish grey of common.

Rump color - a sizeable patch of unstreaked white, not grey, sometimes
(often?) with a pinkish overtone.

Flanks - unstreaked white or with fine pencil like streaking (unlike the
heavy streaking of typical commons)

Breast - white, sometimes (often?) with faint pinkish overtones (not
like the reddish on commons)

Head and bill - this, I think, may be the most important
characteristics. The face of C.h. exilipes has a "pushed in" look. This
is because the bill is much shorter and stubbier than commons and the
culmen of the upper mandible is either straight or may even appear
slightly concave.

Overall shape - C.h. exilipes is often described as being "fluffier
looking" than commons due to the fact that they, apparently, fluff out
their body feathers more.

Undertail coverts - either unstreaked or with limited streaking.

This is as far as my knowledge goes. However, I have to come clean and
admit that this knowledge has not been all that useful in the field!
Over the last few winters I have looked closely at lots of redpolls and
have not seen an undoubted hoary, though I've seen a few possibles. All
of the above characters seem to vary more or less widely. The rump and
undertail coverts are a case in point: I have seen lots of males that
have virtually unstreaked coverts or that have unstreaked white rumps
but that are otherwise typical commons. The head and bill shape (since
it is structural) might not vary as much, but who knows. I am not saying
that hoarys don't occur, or that they are not identifiable, only that
because of my experiences I treat the ID with great caution.

I guess that when faced with a likely candidate in the field my first
criteria are head and bill shape and overall coloration. If the bird
passes those tests, I would then go on to the other characteristics. If
the bird passed all of these tests would I call it a hoary? Maybe, but
I'd be more likely to err on the side of caution and call it hoary-type.


Hope this helps!!!  


 

Hector Galbraith PhD
Galbraith Environmental Sciences LLC
837 Camp Arden Rd., Dummerston, VT05301
802 258 4836 (phone)