Update; January 19, 2001: click
here to see a "normal" green-morph Pine Siskin from
Newfoundland.
This page demonstrates and discusses my recent encounter with
a green-morph Pine Siskin (Carduelis
pinus):
With higher-than-normal numbers of Pine Siskins (PISI) at my feeders
in December, 2001 I had been enjoying close studies of up to six
at a time, and on December 29 I was looking to see if my heavily-marked
bird (see first siskin web page) would make a reappearance; instead
I glimpsed a very bright, yellow-and-greenish individual at my
sunflower feeder, and grabbed a quick snap through the window;
even this fuzzy photo (with a female House Finch behind it) shows
how striking it was:
Luckily it moved to one of my thistle feeders, allowing me to
get better photos:
note in the first image above, the pointed outer tail feathers,
making the green-morph individual a first-basic - compare it to
the more-rounded tail of the adult normal PISI above it (from
Pyle et al's banding guide).
- after a few minutes all the birds flushed; most returned, but
I have not since seen this individual.
- compare a close-up of the wing of the green-morph bird to that
of wing of the normal PISI from the above photo, followed by another
close-up of the green-morph bird from a different photo:
- the bright yellow in the outer retrices made it difficult to
assess the undertail coverts:
I know of two articles describing the green- morph PISI: "Eurasian
Siskins in North America - distinguishing females from green-morph
Pine Siskins" by McLaren, Morlan, Smith, Gosselin, and Bailey;
American Birds, Vol 43 number 5 ( Winter 1989); "Identifying
Eurasian and Pine Siskins" by Lethaby; BIRDING vol 30
number 2 ( April 1998).
The first-referenced article above did the ground-breaking work
on the hithero-undescribed green-morph PISI, and Lethaby largely
re-stated the conclusions in his piece (that focused more on separating
normal PISIs from EUSI). To summarize green-morph birds:
a) they are (thus far) all males, presumed to be examples of schizochroism,
in that the brown pigments are reduced/absent, while the green
and yellow pigments are enhanced.
b) they have larger-than-normal amounts of yellow in the tail
and in the wing base - much more than on EUSI.
c) they have yellow on the flanks and undertail coverts, but not
across the upper breast - EUSI has white undertail coverts and
flanks, with a yellow wash on parts of the face and across the
upper chest (note that Lethaby feels some EUSIs can also have
some yellow on the flanks).
d) the underparts streaking is reduced such that the upper (chest)
streaks resembe the thin streaks of EUSI, but the lower flank
streaking is also thin - very different from EUSI's thick, well-defined
lower flank streaks. The extent of streaking is typical
for PISI in that it meets across the breast, while most EUSIs
have little or no central streaking.
e) The wing bars are typical of PISI in that they are both rather
narrow, with a white median covert bar and a slight tinge of yellow
in the greater covert bar (some of this effect comes from the
bright yellow transverse primary patch showing though the feather
tips), - EUSIs have thicker median and greater covert bars and
both are genuinely tinged with varying amounts of yellow. The Fort Worth bird above appears to establish that some of
these criteria are not reliable, in that:
1) it does have bright yellow in the tail, but nowhere near as
much as in previously documented green-morphs - and I feel it
is within the range exhibited by EUSI.
2) the yellow in the base of the primaries is rather small - smaller
than an average PISI, and again within range of EUSI.
3) The pattern of streaking (but not the extent) is an
extremely good match for EUSI, in that the upper streaks are fine
but the lower flank streaks are thick, blackish and well-defined.
4) The median wing bar is distinctly tinged with yellow, and thicker
than normal for PISI - but perhaps still slightly too thin for
EUSI?
5) The greater wing bar is tinged with yellow throughout its length,
and not mainly as an artifact of an underlying yellow primary
patch - but again it is probably not thick enough for EUSI. NOTE:
there is evidence of wear in the plumage of this juvenile/first-basic
green-morph bird - compare the edges of the tertials with those
of the normal (adult) PISI - thus the wing bars may originally
have been thick enough to match EUSI; all published pics of female
EUSIs are adults (stated, and evident based on tail shape), and
thus probably fresher (= thicker wing bars); for example this
adult female EUSI by Nick Lethaby, from Japan:
So why isn't the Fort Worth bird a EUSI? (apart from the fact
it was in Texas!):
i) the bill looks to be normal for PISI (although I feel there
is some overlap in bill shape with EUSI, and thus this does not
rule out EUSI).
ii) in the field I could not see any yellow on the undertail coverts,
but the photos seem to show a small amount - EUSI has pure white
undertail coverts.
iii) EUSI would have more yellow across the breast, and most have
more yellow in the face (although the FW bird does have traces
of yellow in the supercilium and auricular crescent)
iv) the extent of underpart streaking is at the extreme end for
EUSI and normal for PISI.
v) the wing bars are not thick enough (altough this may be affected
by wear).
vi) the pattern of the folded primaries - see
3rd siskin page.
As always, I would value informed comment
on this page - please indicate whether your comments are to be
considered private/anonymous - thank you.
