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January
2, 2009 - Last November we were surprised to see
a white throated sparrow foraging by double
scratching in the dried leaves under the far
feeders. This one had the black and white stripe
on his head.
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| The latest snow and ice blew in a small flock of
white throated sparrows dancing like mad in the
gentle snow drifts trying to unearth seeds and
goodies. They happily mixed with the cardinals,
juncos, house finches, and mourning doves. As
can be seen from these photos, the mourning
doves learned quickly, that the sparrows could
easily uncover hidden corn and seed. The doves
would follow the sparrows around and jump into
the holes they created in order to find the
larger seeds that didn't appeal to the sparrows.
Good times for all. |
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Our latest crowd of sparrows consisted of both
types of white throated sparrows (the black and
white stripes and the brown and tan version). |
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In
late November 2008 we saw a white throated
sparrow foraging on the ground under the feeders
with some juncos. This version had the black and
white head (sure stands out in a crowd) and, of
course, the yellow spot at each eye. Our
backyard is located at the line between
migration and summer, which makes him a surprise
visitor, but always more than welcome. |
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This distinctive sparrow has
two bright yellow spots from the base of the
beak to the top of each eye. The white throated
sparrow is polymorphic ( two color variations).
The stripes on his head are dark with either
white stripes or with tan stripes. For an as
yet undetermined reason, studies show that a
white striped sparrow will only mate with a tan
striped bird (white striped male with tan
striped female or tan striped male with white
striped female). |
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| Early observers (cited in old
bird books) believed that the tan striped
versions were the juveniles of the white striped
ones. In researching information on the
white throated sparrow I even found a reference
that stated all tan striped sparrows were the
females. |
| But the most astonishing
theory was, while the opposite colors "almost
always" mate, all males (whether white or tan)
prefer females with white stripes. Both
types of females prefer males of tan
stripes. (Who did that survey, anyway?) The
white striped version is more aggressive than
the tan, so the white female will select the tan
male. While the other two may mate by
default, studies show that the tan female is
more nurturing than the white striped one.
And only the white female will sing, as do both
versions of the male. This might be one of
nature's strange trade-offs.
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| Our backyard falls in the
migration transition between only summer and
only winter stays . We first saw the white
throated sparrow on April 25th. That and later
sightings on May 3rd and 6th were all of the
white striped version. It wasn't until I
was ready to do this introduction and after some
research, that I realized I had pictures taken
on May 12th of the tan striped morph along with,
oddly enough, a white crowned sparrow.
Their migration time had overlapped in our yard.
Sure hope we don't miss a return pass through. |
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Size:
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Length: 6-7 in
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Weight: .9 oz
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Wingspan: 8.75-10 in |
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ID:
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Male: Gray underparts with some
darker gray streaking; back, wings and
tail streaked brown and black; bright
yellow supraloral stripe (area between
the eye and the base of the beak); two
separate morphs (white and black striped
head; the other tan and brown striped
head); white or tan throat matching head
stripe; two white wing bars; beak short,
dark gray and sharp; pinkish brown
anisodactylous feet (three toes point
forward and one toe points backward)
Female and Juvenile:Head pattern less
bold than male; dull yellow lores;
grayer throat; streaking on breast more
pronounced
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Habitat:
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Mixed woodland undergrowth; thickets
and bushes; residential areas in winter
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Diet:
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Insects, spiders, seeds (at ground
feeders), and berries; forages on ground
and in vegetation by double scratching
(slight hop forward with both feet, then
a sweep backward kicking aside debris
exposing any food); loves sunflower
seeds
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Family Behavior:
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Mating Habits: Monogamous and
solitary; each breeding pair consists of
one white morph and one tan one; 1 brood
per year
Local Breeding Period: Mid to Late
May
Nests:Cup-shaped; female builds; made
of coarse grass, twigs and wood chips,
and conifer needles; placed at edge of
clearing concealed by low shrub or log
Eggs:4-6 greenish white to bluish white
with reddish brown markings; female
incubates 11-14 days
Nestlings: Born altricial (helpless,
naked, eyes closed) and stay in nest
7-12 days; male and female feed
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Social Activities:
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Joins mixed species flocks in winter
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Range:
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Breeding: Across Canada to extreme
north east US
Winter: Mid to southern US
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Vocalization:
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Clear whistled rhythmic pattern of
notes that begin with two notes on one
pitch and next 3 or 4 on another; call a
loud, sharp chink for alarm or tseet in
flocks
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| Lifespan: |
Up to 10 years |
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