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Cursory glances or occluded views
might lead an obderver to think these three birds were all of
a species, espcially if all were seen proxmally on the the
same day. Superficially the three are similar - ground
foraging birds with erect postures, dark upperparts, obbious
eyering - it could be a whole flock of these guys, or maybe
its an invasion! But let's slow down and cast some
critical focus on structure and on the shape and extensity of
those spots.
A)
Good Photo, Easy Bird
Those of you who have followed
this feature from its inception have seen this species
before. And you should have immediately noticed this
bird's short, conical bill is quite different than the longer,
thinner, straighter bills of our other two quiz birds, for
sure placing it in a different family than theirs.
This bill shape says
"sparrow," and the combination of light bill with
lighter lower mandible and the heavy, sharply triangular
breast spots resembling mountains on a map which coalesce into
one large central spot says "Fox Sparrow." Our
January/February, 1999 quiz also featured a Fox Sparrow, with
the note that "at least one is reported somewhere around
the Valley every winter." This year there were at
least three and possibly four wintering at the
arboretum. That is a flock for species of bird that
isn't considered a flocking species!
End of story? Not
quite! Some ornithologists, though acknowledging zones
of intergradation, consider the four main subspecies of Fox
Sparrow to be separate and distinguishable, and the species
may be taxonomically split if and when DNA studies are
completed. The "Red" Fox Sparrow, the nominate
subspecies, iliaca, breeds across the northern taiga
and winters primarily in the southeast.
"Sooty" and "Slate-colored" Fox Sparrows, fuliginosa
and schistacea respectively, breed in the northwest and
winter in the southwest. The
"Thick-billed" of California, stephensi,
closely resembles Slate-colored by has a massive bill.
The consensus of experienced
birders who saw multiple Fox Sparrows at the arboretum this
winter was that there were two Sooties and at least one
Slate-colored present. Our quiz birds is one of those
Sooties, photographed last October, showing little or no
facial contrast and heavy spotting extending all the way down
the flanks. Slate-coloreds often have little or no
spotting on the belly and lower flanks, a noticeably paler
loral area, and enough of a lower face pattern to be
considered sub-moustachial and malar stripes. My side
view slides of our quiz bird showed no wingbar and dorsal
contrast, whereas my slides of the Slate-colored showed a
faint but distinctive wingbar and a definite contrast between
gray back and rump and red wings and tail.
B)
Good Photo, Difficult Bird
Were this quiz in color and
our quiz bird's tail not partially in shadow, this would not
be a particularly hard bird to identify. The think,
straight bill, the icy stare rendered by the proportionately
large eye on the relatively plain face, the just-popped-erect
posture, and the speckled breast pattern tell us immediately
this is one of our spotted thrushes. In fact, those same
filed marks say the same thing about our third quiz bird
too. There are six possibilities. Let's eliminate
Bicnell's, based on geography, and see if we can sort out the
remaining five.
Our quiz bird has a thin,
petite jizz. It shows no face pattern other than its distinct
eyering and a thin, dark malar stripe. Its spots are
bold and dark against a white background, at least on the
chest, but they are not crisp. They run together forming
streaks, continue down the flanks becoming indistinct, and
fade out against a background which could be gray or brown but
is decidedly darker than our bird's white chest.
Wood Thrush is a spotted
thrush, but it belongs to the genus Hylocichla. It is
the biggest of our spotted thrushes, its larger size usually
apparent because of its relatively plump body and
proportionately large head which often appears peaked because
this species raises its crown feathers when agitated.
Woodies have bold white lores and eyering, distinctive
horizontal black and white streaking on the ear coverts, and
crisp. almost perfectly circular spotting that extends down
the flanks, all the way on |
a clean white
background, but stops at the lower belly. This
description does not fit our second bird, so let's explore the
four remaining species which, in addition to Bicknell's,
belong to the genus Catharus.
Separating the Catharus
thrushes without benefit of color is going to be an exercise
in oversiplification. It will grate on the purists, but
remember that the purpose of the quiz is not to make you an
identification expert but to give you some starting points,
some building blocks, and for this genus of structurally
identical species, we're going to have to do it with plumage
features.
Veery shows an indistinct
eyering and a very weak malar stripe. Its spots are weak
and light against a buffy background which is decidedly darker
than its white belly. It has gray flanks but its spots
do not extend down into the flank area. This is not a
Veery. Veery is possible but not to be expected in fall
migration in Arizona. It has nested locally in the White
Mountains in the past, but not recently. If you
see a Veery in Arizona, he Arizona Bird Committee wants
documentation.
Swainson's Thrush typically
displays the strongest face patterns of the Catharus
congerners. It will show a warm and distinctly buffy
eyering and loral area which gives the species a pronounced
"spectacled" appearance. It has dark spotting
which runs together to form streaking against a warm, buffy
background which fades to off-white on the belly. Based
mainly on our quiz bird's rather plan face, this is not a
Swainson's. Swainson's nests locally in the White
Mountains and is rare fall migrant.
Gray-cheeked Thrush has no
face pattern at all. The eyering is indistinct and
incomplete through there may be a thin, dark malar
stripe. It is heavily and darkly spotted against a
light, buff to off-white background. It has the darkest
and most extensively colored flanks of the Catharus
thrushes. Based mainly on our quiz bird's bold and
complete eyering and its very light, probably white, chest
color, this is not a Gray-cheeked. Gray-cheeked is an
accidental fall migrant in Arizona, not to be expected.
If you see a Gray-cheeked Thrush in Arizona, the Arizona Bird
Committee wants documentation.
The Hermit Thrush was
photographed at the arboretum in January, '02. Without
the benefit, in living color, of the contrasting reddish tail,
without the consideration of probability, and with the
presence of at least half a dozen other Hermies (a veritable
flock!), I believe this bird could for sure be passed off as a
Gray-cheeked, possibly as a Swainson's, but probably not as a
Veery and certainly not as a Woody. Hermies are common
breeders in Arizona's mountains, common migrants throughout
the state, and are not hard to find in the lowlands in the
winter. They are in fact, the only thrushes found in the
U.S. in winter. Based on this bird's white chest, it is
probably the Rocky Mountain subspecies. Watch for
Hermits' distinctive behavioral characteristic of cocking and
then dropping the tail, particularly after landing.
C)
Bad Photo, Easy Bird
Often when a
bird is partially occluded by vegetations, I will take the
shot anyway if the face is unobstructed and sharply
focused. I always think it's going to look cool to see
the sharp eye peering out through the unfocused
foreground. Wrong! Either the bird gets lost in
the overly busy frame or, as in this case, it looks like I
photographed part of my thumb, and the lower half of the bird
is soft or muddy. This contrast between sharp and soft
never seems to be appealing to the eye, no matter how many
ways I try it.
Based on the
plumage characteristics we've discussed, how would you
describe this third quiz bird? It's all right up there
in the paragraph beginning with "Wood Thrush...."
isn't it? This is the Woody discovered at the arboretum
in the fall of 1991 by Anita Van Auken, The quote from
my notebook the day I took this photograph reads "It's
great to see this fat, dapper thrush here in the desert after
looking at so many plain littler Hermits all these
years."
One of my most
memorable early birding experiences was seeing all five
spotted thrushes within two days on my first trip to Pelee in
mid-May of 1981. Another place to study them
side-by-side is the upper Texas coast, third week of
April. And you might see them together again in this
space too.
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