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White-crowned
Sparrow
Zonotrichia leucophrys
[Eastern White-crowned Sparrow]
Contributed by Roland C. Clement
[Published in 1968:
Smithsonian Institution United States National Museum Bulletin 237
(Part 3): 1273-1291]
The tremendous energy which drives small birds toward their
breeding grounds in spring is well illustrated by the way in which
some of them overshoot their destination. Witness the occurrence
of the eastern race of the white-crowned sparrow on Fletcher's Ice
Island (T-3) on June 16, 1957, when it was at 82o37'
N., 99o50' W., only 150 miles
from the North Pole and some 2,000 miles beyond the nearest
nesting habitat of the species, as reported by Spencer Apollonio
(1958).
Because unusual observational opportunities are required to
recognize such events, we are less aware of them than the facts
probably warrant. But it is this sort of random exploration of
extralimital territory that helps account for the ability of so
many species to colonize new territory as soon as it becomes
suitable. We know, today, that the margin of the tundra which
forms the northern limit of the white-crown's range has been both
farther north and farther south during the last10,000 years, and
that the range and the population of this species have varied
accordingly.
The eastern white-crown is best described as a subarctic and
alpine zone bird, but so extensive is its range that only
ecological characterization is really helpful. This has seldom
been done and as a result "life zone" pigeon-holings are
rampant with apparent contradictions. The only full awareness of
the ecology of this bird in all the material before me is Harrison
F. Lewis' excellent description, in a letter of July 1,1963:
"In coasting along the north shore of the Gulf of St.
Lawrence from west to east, in latitude slightly north of 50o,
one enters the breeding range of the white-crowned sparrow
abruptly on passing Saint Genevieve Island, the easternmost of the
Mingan Archipelago. The reason for the abruptness of this boundary
is that the Mingan Islands, which border the coast for some 50
miles, are formed of limestone, as is, also, much of the adjacent
coastal mainland. Eastward from Saint Genevieve, the mainland and
the coastal islands are of acidic pre-Cambrian rocks, such as
granite and gneiss. The vegetation of the limestone belt is much
superior to that which grows on the adjacent pre-Cambrian rocks,
and the bird life reflects this; for example, the ovenbird nests
on the limestone of the Mingan region, but not beyond. West of
Saint Genevieve I have only a few records of sporadic occurrence
of the white-crown in the nesting season."
This Mingan region is an outlier of Paleozoic rocks. In his
monumental photo-reconnaisance of the vegetation and physiography
of the Labrador-Ungava peninsula, F. Kenneth Hare (1959) marks it
as the eastern terminus of the Laurentide massif and considers it
an outlier of the coastal tundra that fringes the southeast coast
of Labrador. Climatologists bring the 55o
F. July isotherm, which transects the peninsula from west to east,
to the coast just east of this region, and forms a rough boundary
between the open subarctic woodland to the north, the closed-crown
forest to the south and west, and the scrubby forest
characteristic of the eastern tip of the peninsula at this
latitude.
It is open, stunted tree growth and brush that attracts nesting
white-crowned sparrows. At Goose Bay, Labrador, for example, I
found them nesting only in the open, often burned, black spruce
and dwarf birch on the high, sandy delta of the airport plateau.
In better sites nearby, white-throated sparrows nested. An
awareness of such temporary ecological changes in distribution
allows me to view with interest the nesting reports of
white-crowns at North Bay, Ontario, and at Baie Comeau and Godbout
on the north shore of the St. Lawrence, as well as near Godthaab,
Greenland, in 1824 (Salomonson, 1950); though I cannot credit them
for lack of corroborative details on the ecology of the site.
Despite the fact that it was the first known and is the most
widely distributed race, the eastern white-crown has been one of
the least studied. No one has yet reported in any detail on the
biology of the alpine populations of the Rocky Mountain massif,
and the eastern group has only recently begun to attract the
attention it deserves. In a study of geographic variation in the
entire leucophrys group, Richard C. Banks (1964) reduces
Harry C. Oberholser's (1932) Cordilleran race oriantha to
synonymy with the eastern race, discounts W. E. Clyde Todd's
(1953) proposal of the name nigrilora for the "ultratypical"
Labrador peninsula population, and considers the slightly larger,
reddish-backed and black-lored nominate leucophrys to be
the ancestral population. "The species," he writes,
"appears to be essentially a northern one which has extended
southward only where summer conditions approximate those found in
subarctic regions. Thus, in the western. . .United States,
White-crowns are found only in high mountains and along the cool
Pacific coast."
Spring.--The interaction between
internal and external factors in the eastern population remains
almost unreported. Only Marshall B. Eyster (1954) has shown that,
compared to such congeners as the white-throated sparrow and the
junco, the white-crown is much more prone to pre-migratory
nocturnal unrest (zugunruhe).
Viewed from the central wintering grounds of the southern Great
Plains, the spring migration involves a radiation northward. One
population segment goes northwestward into the Rocky Mountain
uplands, another more or less due north to the Cypress Hills of
Saskatchewan and the Hudson's Bay country, but the largest segment
trends far to the east of north, to summer in northern Quebec and
western Newfoundland.
In an analysis of 198 recoveries and 9,107 returns from
nearly 232,000 white-crowns banded between 1920 and 1963, Angelo
J. Cortopassi and Richard L. Mewaldt (1965) show that migration is
of a broad-front type and not oriented to landmarks--of 6,000
birds banded while on migration, not a single individual returned
to the place of banding. Migration is by hops of at least 200
miles, with one 310-mile hop recorded in spring, and with a daily
mean of about 50 miles. One bird banded by Ralph K. Bell at
Clarksville, Pa., May 6, 1962, was recaptured 1,500 miles to the
north at Battle Harbor, Labrador, on June 12, having averaged 40
miles per day.
The rapid northward surge of this species results in "a
high fidelity of timing" as Cortopassi and Mewaldt put it--94
percent of the birds pass through 1,000 miles of the northeast's
most populous countryside between May 2 and 18, with May 11 the
median date for banding migrants in this region. Milton B.
Trautman (1956) gives the principal movement at Buckeye Lake,
Ohio, as May 8 to 20. In a letter to Ralph K. Bell, Gordon Wilson
of Bowling Green, Ky., who has chronicled the birds of his region
for 45 years, gives average departure as May 10, with May 28 as a
late date.
The only evidence of physiographically-controlled spring
migration I have seen is a letter from Clark S. Beardslee to Mr.
Bent in 1951, reporting that in spring northbound white-crowns
move eastward through Ontario, cross into New York State in the
Buffalo-Niagara isthmus, then presumably circle eastward around
the south side of Lake Ontario before moving northward into
Quebec. Harold D. Mitchell has kindly confirmed these observations
for me.
Dispersal into the subarctic breeding grounds on the interior
Quebec-Labrador plateaus normally occurs during the last week of
May, though late ice and snow may sometimes delay arrival a whole
week. I was impressed by the influence of seasonal conditions when
I arrived at Knob Lake in interior Quebec on May 18,1957. A raging
blizzard made it plain that winter's grip was still firm.
Returning to within 15 miles of the St. Lawrence above Seven
Islands, I found white-crowns abundant and obviously "dammed
up" by weather, for they were occupying all sorts of habitats
that are not usual for them. They sang softly while awaiting
better conditions for concluding their migration. The first birds
arrived at Knob Lake on May 23 that year, but even so, they had to
spend several days feeding along plowed roadsides until the snow
melted from the territories they were to occupy. Harrison F.
Lewis' notes show that conditions were even more severe a decade
earlier; his June 4, 1947 journal entry records that this
"was an abnormally cold, late spring, with consequent heavy
loss of life among small migrant passerines." He recorded 120
obviously delayed migrant white-crowns at Seven Islands, south and
west of the breeding range.
Territory.--Territorial behavior
has not yet been described for this race of the white-crown. I
have twice seen fights in early June in the Knob Lake region, the
birds facing each other breast to breast, then jumping, clawing,
and flying at each other. Such jousts are usually short-lived.
The white-crown does best in "hybrid" habitats, where
disturbance of the surface by fire or mechanical means has
increased diversity and the shrub growth is still young. Under
such conditions I have found two nests only 300 feet apart, and
computed territory sizes as between .88 and 1.85 acres each. On
the other hand, a breeding bird census of 18 1/2 acres of open
lichen woodland--the most extensive vegetative type of central
Labrador--revealed a low density of two nests, or about 1
territory per 9 acres. This would be about 70 pairs per square
mile, but Thomas H. Manning (1949) estimated that in western
Ungava the population was between 10 and 30 pairs per square mile,
the higher counts being in burnt areas.
Courtship.--The sexes being
alike, it is difficult to follow territorial disputes and
courtship until birds have been color-marked. No one has yet done
this early enough in the season to unravel this phase of the life
history of the eastern subspecies.
Within a week after arrival on the breeding grounds a good deal
of territorial song is heard from about 5:00 a.m. to 10:00 a.m.
and again in the evening. For a week or so thereafter the birds
utter much high-pitched trilling with depressed crowns, either
from the ground or from no more than 4 feet above it. This trill
is quickly communicated to the whole nearby group, several other
birds then repeating it. The trilling bird often attracts a
companion who approaches with crest high and loud pete
notes, as though alarmed, and they fly off together. Three-party
nuptial chases are common at this season. More specifically, the
bird that emits the high, trilling dreeeee note often
crouches low, with head up, and flutters its wings as though
rotated from the "wrist." I did not notice the
tail-spreading and the spasmodic wing opening and closing that
caught the attention of Francis Harper (1958) in this same area.
As I proved by collecting, the female gives a loud chatter during
these mating chases (this female contained oocytes up to 1
millimeter in diameter). Two weeks after the population arrived,
while trilling was going on everywhere, I saw a female crouch and
trill (I wrote whimper), and the male then mounted quickly three
times. Soon afterward song fell off noticeably.
The male of the eastern white-crowned sparrow seems to share
some notes and postures heretofore (Nice, 1943, and Blanchard,
1936) ascribed to the female only. On June 13, 1957, I collected a
trilling, wing-flipping bird that turned out to be a male. Error
is easy under the stress of collecting in close quarters, and a
male that entered unobserved may have been the inadvertent victim
of my search during the few seconds involved; but, again, on June
24, 1958, I saw a color banded male, the mate of a female with
eggs in the nest, rotate its wings "at the wrist," in
the slow wing-flutter that the female gives while trilling in
invitation to copulation (Blanchard, 1936).
Nesting.--Whereas Alfred O. Gross
(1937) could write that "the height of the breeding season of
the White-crowned Sparrow on the Labrador coast is during the
first two weeks of July," for the Labrador peninsula as a
whole, most eggs are laid by mid-June. This varies greatly from
season to season, however, and from region to region; the season
in the higher southern third of the vast peninsula, for example,
is usually later than in the lower areas farther north.
In mid-morning on June 16, 1957, I surprised a bird forming a
nest. It had pulled out mixed hairy-cap mosses and Cladonia
lichens for a proper cup in the shade of a dwarf birch. From a
total of some 30 nests examined in situ, it seems safe to
consider my description (in Todd, 1963) as typical: "four
inches in outside diameter and two and five-eighths inches inside.
The inside depth was one and one-half inches. The main body of the
nest is woven of fine grass stems, the outside is made up of mixed
moss stems, and the bottom is lined with very fine root fibers, or
in one case with white ptarmigan body-feathers." Harrison F.
Lewis (in litt.) once found a nest lined with light gray
hair, perhaps that of a dog. Most nests set into the moss-lichen
or lichen-crowberry mat are partly concealed by overhanging
branches of dwarf birch or Labrador tea; not infrequently a nest
is neatly tucked into the lower side of a moss or crowberry (Empetrum)
mound. Much less frequently, nests are built into moss hummocks on
a string of heath shrubbery some distance out in a sphagnum bog.
Although I have never seen an elevated nest, Arthur A. Allen wrote
me that whereas all the nests he had found in the Churchill region
were on the ground, on the Labrador Coast (North Shore) "the
few nests I saw were in small firs." Earlier, Oliver L.
Austin, Jr. (1932) had quoted Moravian missionary Perrett's notes
from Makkovik, Labrador, concerning a nest "about three feet
from the ground in bushes thrown over a boat to protect it from
the sun."
On June 30, 1957, I found an otherwise typical white-crown nest
in a "hybrid" habitat near the airport at Schefferville
(Knob Lake), Quebec, which contained 8 eggs and had 3 birds in
attendance. On July 2 the eggs and the two birds that came to
incubate between 10:45 a.m. and 1:30 p.m. were collected by Don R.
Oliver of the McGill University Subarctic Laboratory and shipped
to me at Brown University, where William Montagna dissected them.
Both birds were females in comparable stages of gonadal
regression, with equally developed brood patches. One bird showed
two clear follicles and what appeared to be two coalesced
follicles; the other had three clear follicles and one
questionable follicle. Although polygyny has been reported in
Emberizines before (e.g., corn bunting) this appears to be the
first American record and is unusual in that only one nest was
involved.
Some pairs may mate a second time. On July 10, during their 7th
day of caring for young, the banded pair I had under observation
at Schefferville, Quebec, performed elements of the nuptial
display. The female trilled and fluttered her wings as she left
the nest; later I heard her trill while out of sight behind my
blind and thought that the sounds indicated a mating chase; that
same day the male twittered on crossing her in flight as they
exchanged visits to feed the young. E. P. Wheeler, II (in
litt.) once found a bird with unhatched eggs as late as July 30 on
the Labrador coast.
Eggs.--The white-crowned sparrow lays
three to five, and rarely six eggs. They are ovate, though some
may tend toward either short or elongate ovate, and are slightly
glossy. The ground is pale greenish or creamy white and is heavily
marked with spots and blotches of reddish browns such as
"Natal brown," "Mars brown,"
"chestnut," "Verona brown," or
"russet." There is quite a range of variation;
frequently the spottings obscure the entire ground, while in other
cases considerable ground is showing with the markings
concentrated toward the large end where they may become confluent.
On eggs with much ground showing, undermarkings of "pale
neutral gray" may be discernible.
The measurements of 50 eggs of Z. l. leucophrys average
21.5 by 15.6 millimeter; the eggs showing the four extremes
measure 24.1 by 16.5, 21.6 by 17.0, 18.9 by
15.8, and 19.8 by 14.5 millimeters.
Of 29 sets recorded, 23 sets had four eggs, 5 had five eggs,
and only one had six eggs. I therefore assume the three-egg
clutches occasionally reported are probably incomplete.
A color-banded pair had four eggs on June 24, 1958, when
discovered, and hatching occurred July 4, so incubation
is at least 11 days. The female did all the brooding of the young,
so it seems likely that she also did all the incubating of the
eggs, as I found her on the nest after dark. Another bird was so
bothered by the wind flapping my blind during a 3-hour watch that
she was off the nest as much as she was on; she changed every 1
1/2 minutes as a rule, and her longest periods on the eggs were 6
to 7 minutes.
Young.--I found that for the first
and second days after hatching, the female turns the young, just
as she turned the eggs earlier, at 10- to 20-minute intervals. Her
brooding schedule is controlled by the male's visits, for she gets
off the nest when he brings her food. He comes silently and
directly to the nest, whereas she lands10 to 15 feet away, always
on the same side, then hops in slowly, nearly always using the
same perches. On reaching the nest she gives a few alerting chips,
to which the young make no vocal response until the 5th day, and
the male responds to their trilling only after the 7th day. In
1957 I noted:
"It is surprising to see how well the pale lining of the
female's feathering causes her to blend unobtrusively with the
straw border of the nest as she broods. The young grow so quickly
that on the third day they push up the female, beg, and gape
without parental provocation. They nestle deeply into the nest
when the sun dips in late afternoon. On the fourth day their eyes
are open during shady intervals, and fully open the next day. They
hug the nest when the female scolds and no longer gape at my
touch. The tail feathers are now one quarter inch long.
"By the seventh day the female has trouble brooding since
the young toss and turn. The next day they scratch and preen for
the first time, and anticipate the parent's return by
trilling."
Feeding and nest-sanitation are shared almost equally by the
parents, the male making slightly more than half the feedings, and
removing slightly more than half the fecal sacs. Usually the old
birds carry the fecal sacs away, but they occasionally eat the
small ones. On their 8th day the young receive feeding visits on
an average of one every 10 minutes. On the 9th day they will leave
the nest if disturbed, but probably stay on another day or two
when not pressed.
Plumages.--One-day-old young are
fluffy in mouse-gray natal down which covers capital, dorsal, alar,
and femoral tracts, but not the ventral tract.
My Labrador notes contain a description of a fledgling about 2
days off the nest. It had dark brown eyes, the bill was brown, and
the gape and most of the commissure corn-yellow, the tarsus lilac,
and the toenails light horn gray. Francis Harper (1958) describes
a young bird as having vermillion mouth linings, with commissure
and tomia corn-yellow.
Richard R. Graber (1955) describes in detail the juvenal
plumage on the basis of a bird from Colorado and another from
Labrador:
"Forehead and crown streaked throughout with black. Crown
and forehead white medially, brown laterally. Occiput dark,
mottled brown and black. Nape mottled, white and black. Back
streaked, black and buff. Rump and upper tail coverts rusty-buff,
streaked with black. Rectrices and remiges black. Primaries edged
with buff, secondaries and tertials with dull rust color.
Uppermost (proximal) tertials edged and tipped with buffy white.
Lesser coverts gray; medians black, edged with white; greater
coverts black, edged with buff, tipped with white. Two white wing
bars. Lores dark, brownish or gray. Narrow white supra-ocular
stripe from eye to nape. Auriculars buff-tinged gray,
post-auriculars like nape. Chin and throat white, flecked with
black, and with black "mustache" marks. Under parts
white, or lightly tinged with buff on chest, sides, and crissum.
Chest, sides, and flanks heavily streaked with black. Belly and
crissum immaculate. Leg feathers dark brown, edged with
white."
Jonathan J. Dwight (1900) presumes that the first winter
plumage is "acquired by partial postjuvenal moult, probably
in August on its breeding grounds, which apparently involves the
body plumage and the wing coverts partly but not the rest of the
wings nor the tail." This is the "brown Livery,"
the conspicuously more buffy immature plumage, in which the head
is marked by broad reddish-brown stripes instead of the black and
white of the adult.
Dwight also writes that first nuptial plumage is "acquired
by a partial prenuptial moult beginning the end of March which
involves chiefly the head and chin and a few scattering feathers
elsewhere. The black and white crown is assumed, which soon shows
nearly as much wear as the rest of the plumage. This becomes
grayer and the stripes clearer. Old and young become practically
indistinguishable" at this stage. Furthermore, "adult
winter plumage is acquired by a complete postnuptial moult."
Robert A. Norris (1954) reports an extensive prenuptial molt
during March and April, except for "the alulae, the
primaries, secondaries and their greater (outer) coverts, the ten
outside tail feathers, and some of the feathers of the "wing
lining." He felt it was "fairly certain that nonmolting
birds such as my mid-March specimens would show. . .overlap
between periods of molt and migration," assuming that
completion of the molt requires 2 months.
Amelia R. Laskey of Nashville, Tenn., wrote Mr. Bent that she
noticed unusually early beginning of crown molt during the first
week of November 1932 and again in1934. In the experience of both
Mrs. Laskey and Ralph Bell, crown molt is normally complete by
late April. Bell's notes show that crown molt takes at least 20
days.
Food.--Perhaps the most interesting
item on the food of white-crowns is Francis Harper's (1958)
discovery that in spring on the breeding grounds, these birds eat
the green capsules of Polytrichum juniperinum, the
hairy-cap moss. In 1957 I watched one bird pick and eat 120
capsules in exactly one minute. A female collected on June 8 had
nothing but these capsules in her crop, and though all the
white-crowns were utilizing this food at the time, some birds also
picked up small brown seeds, a few sand grains, and black flies (Simulium
sp.).
Like other terrestrial passerines, the white-crown is an
opportunist. The hairy-cap moss capsules it consumes in late May
and early June, when snows have just melted but before many
insects emerge, are at that time the most available food. I have
watched them eat the new green catkins of willows. The young are
fed insects as nestlings, and themselves catch flies, mosquitoes,
and spiders, as everyone who has studied them has noticed. In
winter they are primarily seed eaters, and in spring or any other
time these are available, they take fleshy fruits such as the red
mulberry or the crowberry.
Behavior.--The white-crown has
long had the reputation of being an aristocrat among the
Emberizines. His neat attire, striking crown, and his habit of
stretching his head upward to look around have probably combined
to earn him this title.
But nobility should imply natural dominance. It was not until I
saw white-crowns nesting adjacent to white-throated sparrows at
Redmond Lake south of Schefferville, Quebec, that I realized that
the white-crown is more mousy than regal in bearing, at least in
summer. I found white-throats more deliberate, less upset by
intrusion, their alarm notes a quiet announcement of awareness,
and their flights shorter. White-crowns, on the other hand, were
much more high-strung, always running while on the ground--even if
they did this by hopping with both feet--and their alarm notes
were more insistent, sharp, or nervous. These differences have an
environmental basis, as the white-crowns occupy open country where
they are more exposed to potential enemies and pressed by the
wind, whereas the white-throats occupy the sheltered brushy
borders of the closed crown, Canadian-zone woodland that here
reaches a northern limit.
This demeanor changes on the wintering grounds. Albert F.
Ganier of Nashville, Tenn., who has studied their ways since the
turn of the century, writes me that in his region the white-crowns
remain in compact groups of 10 to 20 birds, hugging the same
habitat week after week, either in a weed- and brush-grown fence
row along some little frequented road, or in an abandoned piece of
farmland where plant succession is throwing up clumps and patches
of herbaceous and sapling growth. "Here," he writes,
"they feed quietly on the ground, but when intruded upon rise
to the top of the low growth and eye the intruder with apparent
curiosity, rather than with fear. They crane their necks to get a
better look and it would appear that they have not yet evolved a
fear of man to the extent of most other birds." They are
apparently not easily flushed out of these preferred coverts, as
are the white-throats that fly ahead of the intruder.
Woodward H. Brown (1954) was impressed by the aerial feeding of
white-crowns and saw them "occasionally spring 15 -18 inches
in the air, returning to former positions on grape vines, catching
gnats or other small insects."
In Quebec-Labrador I was impressed by the fact that females
when disturbed always sneaked off the nest for 10 or 20 feet in a
sort of "mouse run," but without the wing-dragging
display that shore birds and other species often add before
sounding any alarm. On July 3,1958, while crossing a very wet
sedge bog near Lake Matamace north of Schefferville, I watched a
white-crown, which I took to be a male, catch insects by running
in water up to its "knees," throwing up its tail,
raising its white crest high, and "flashing" its wings
much as a mockingbird does to flush out the insect life from the
bog mat.
On July 10,1944, at Goose Bay, Labrador, I flushed a pair of
anxious adults and after 10 minutes of hunting finally drove out a
close sitting fledgling which a companion and I captured with
difficulty. It was interesting that three adults drove at us
frantically as we chased the young bird. They decoyed boldly with
the "broken wing" feint, and drew me 40 feet from the
young one, returning to me each time I hesitated in following.
In 1958 at an elevation of 2,600 feet on Irony Mountain in
central Quebec-Labrador, Henri Ouellet of the Canadian National
Museum watched a white-crown feed a still-downy willow ptarmigan.
E. P. Wheeler II, who has shared notes made during many years of
patient field work in Labrador, noticed that white-crowns
sometimes scratch for food very vigorously, using both feet at
once as the fox sparrow does. This trait, and the tendency of
white-crowns to take easily to man's newly created habitats in the
northern wilderness, as song sparrows and their western congeners
do farther south, raises interesting questions about the
relationship of all these species. Raymond A. Paynter, Jr. (1964),
in the course of a review of some North American Emberizinae,
reaffirms the view that the basic differences between the song
sparrows, the fox sparrows, and the crowned and white-throated
sparrow groups are not clear-cut, and therefore urged that the
genera Melospiza, Passerella, and Zonotrichia
be merged. The existence of hybrids among the white-crowns
(Miller, 1940), between the white-crown and the white-throat
(Abbott, 1958), and between the white-crown and the song sparrow
and the white-throat and the junco (Dickerman, 1961) lends
impressive weight to the Paynter proposal.
Voice.--Often as I sat in the dusk
in my tent or some miner's shack in the iron ore belt of interior
Labrador in 1957, the song of the white-crown reminded me of that
of a diminutive eastern meadowlark. "Especially is this so in
chorus," I wrote, "and the first two notes are often
like the black-capped chickadee's sweet-ee call." I
syllabified one common version as, "teu-dee. . .et tu
aklavik," a phrase which will mean more if pronounced in
French. Everyone recognizes this song as like an imperfect
white-throated sparrow song. To Ludlow Griscom it had the quality
of a black-throated green warbler song, while Francis H. Allen
wrote Mr. Bent that to him the song was "doleful rather than
plaintive--the sweet expression of a state of utter boredom, as if
the bird were saying, 'Oh, well, what's the use?"'
Harrison F. Lewis told Arthur A. Allen that he rendered the
song as "Oh gee--it was the whiz-whiskey," to
which the fox sparrow, so often a neighbor in the northland, would
answer, "Well, my dear, why did you take it?" The
open, windy nature of the semibarrens that the white-crowns occupy
in summer diminishes the impression their song makes on human
visitors; so many songs are wafted away on the wind that only
dominant phrases force themselves on the traveler's attention. The
word renditions given above are the subjective efforts of
pre-technological field ornithology. Today's field students use
tape recorders and analyze their input from the visual record of a
sound spectrograph that allows direct reading and comparison of
duration and pitch. Donald J. Borror (1961) has analyzed a number
of white-crown song recordings made by W. W. H. Gunn in northern
Ontario and has provided the following objective description:
The song usually begins with one to three clear whistled
notes that are steady in pitch, and ends with three buzzy notes,
the last lower in pitch than the two preceding. The first note is
about 0.5 sec in length; if there are two or three similar
introductory notes the second and third are a little shorter. The
final buzzy notes are uttered at three to four per sec. Sometimes
there are short clear notes or two-note phrases in the middle of
the song and sometimes the second or third note of the song is
slurred. One or two of the final buzzes (except the last) may
begin with a short sharp note or be slightly up-slurred or both.
Some songs end in a low trill rather than a low buzzy note. The
songs of a given bird are usually very similar, but those of
different birds often vary slightly.
The pitch of the white-crown's song is between 2,600 and 7,200
cycles per second.
Morning and evening song periods usually involve 15 to 20
minutes of uninterrupted song, and as each song is of 2-second
duration and the interval between songs is 9 to10 seconds, the
total output during such a burst may be 100 or more songs. I have
counted 194 consecutive songs.
Francis Harper (1958) writes the principal call note as "a
tsit, which, when heard near at hand, seems to have a
slight metallic rasp." Charles W. Townsend and Glover M.
Allen (1907) distinguished a metallic chink call note from
a sharper chip alarm note. In my field notes I described
the call note as pete, identical by both sexes, and the
alarm notes as higher pitched than the ordinary scold note.
Amelia R. Laskey (in litt.) mentions a ventriloquial
song of the immature as follows: "At first the songs, coming
at intervals, seemed to emanate from shrubs some 15 feet behind
the bird, but as it came closer I could see its bill open and
close. It was a lengthier song than the adults give in spring, and
the bird erected its crown feathers as it sang."
Mortality.--It seems to me better
to get away from the connotations of the word "enemy"
and simply to point out that the white-crown is subject to the
usual factors that cause attrition in animal populations, whether
disease, the complex of factors engendering winter mortality, or
direct predation by accipitrine hawks, shrikes, weasels, and the
like.
It has its normal share of parasites, both external and
internal. Oscar M. Root has kindly furnished a note on the
identification of Hippoboscid louse-flies, Ornithomyia
fringillina, found on immature birds by Gary C. Kuyava in
Minnesota; Francis Harper (1958) has taken a mite of the genus Lealaps
from a juvenile specimen in Quebec; and Robert A. Norris (1954)
found biting lice (Mallophaga) on dried skins and also found that
four out of nine specimens examined in Georgia had protozoan
infections of the blood (Leucocytozoon), and one of these, a
smallish individual which had not begun its prenuptial molt on
March 17, was doubly infected with the malarial parasite,
Plasmodium. One adult was heavily infected with abdominal
helminths, the filarid nematode Diplotriaena. The
individual infected with Plasmodium also had foot tumors caused by
the virus Epithelioma contagiosm. Alfred O. Gross (1937)
reports the mallophagan Philopterus subflavescens (Geof.)
from young on the Labrador coast, and Herbert Friedmann (1938)
reports parasitism by the cowbird at Okotoks, Alberta.
Of greater population significance, probably, is the loss of
young birds during the first migration. For the Quebec-Labrador
segment, especially, this must be a significant decimating factor
because the young of the year are often wind-drifted out to sea,
where they perish unless they are fortunate enough to reach an
island from whence they can return. I have been particularly
impressed with this problem in their lives at Block Island, R.I.,
where hundreds of white-crowns appear in autumn, when cold fronts
pass out to sea, all of them immatures.
Fall and Winter.--Young
were on the wing as early as July 11, 1945, at Indian House Lake
in northern Labrador, and Austin (1932) saw young flying on July
16, 1928 on the coast, although late July is a more normal date
there. In August at Indian House Lake they were in loose family
groups, feeding and playing in the alder strand that fringes the
George River, and by mid-September when they leave the region,
they are usually restricted to dwarf birch thickets in timberline
areas on the slopes. On July 31 and again on August 3, 1957, at
Scheffeville, Henri Ouellet noted a goodly number of both adults
and young in the open, "feeding very little, and seemingly on
the move." E. P. Wheeler's last date for Kutsertakh on the
Atlantic slope of Labrador is Oct. 5, 1934.
At Buckeye Lake, Ohio, Milton B. Trautman (1940) records first
arrival as October 1 to 8, with the peak of migration October 10
to 27, and the last departure November 3. White-crowns first
wintered there in 1953. The ratio of immatures to adults, M. B.
Trautman reports, was usually 2 to 1, though in some years there
were 97 immatures to 3 adults. As earlier mentioned, on Block
Island, 10 miles off the Rhode Island shore, immature birds are
almost or quite alone, which suggests that adults are too
experienced to allow themselves to be wind-drifted out to sea
during migration. Robert A. Norris (1954) reports a wintering
flock of 30 immatures to 1 adult in Georgia; he considered the sex
ratio balanced.
Concerning autumn habitats, Milton B. Trautman (1940) writes,
"As in spring, the birds were found in brushy situations, but
many were also present in dense patches of high weeds, and in
weedy uncut cornfields. Autumn sparrows were somewhat more
secretive than were spring birds, and it was only by remaining
quiet in a dense weed patch or brushy thicket and giving a Screech
Owl whistle that a true indication of numbers could be
obtained."
Robert A. Norris (1954) writes that white-crowns do not flock
with other species and that on the Georgia wintering grounds he
studied, the birds are "found in more open country with less
cover and also farther from water than is typically the case with
White-throated Sparrows." The March-April weights of his
Georgia birds ranged from 23.7 grams for the smallest female to
31.2 grams for the largest male, the 13-bird sample averaging
30.05 grams. In a larger sample, however, Paul A. Stewart (1937)
found that 21 adults ranged from 19.9 to 37.1 grams, with a mean
of 31.26 grams; 31 immature birds ranged from 23.5 to 32 grams,
with a mean of 27.56 grams.
Cortopassi and Mewaldt's (1965) plot of the distribution of
this species from the Christmas Bird Counts of Audubon Field
Notes shows that the wintering population has two centers of
concentration, one in western Texas and southeastern New Mexico
and the other in the Appalachian plateau and its western
extension, the interior low plateaus and Ozark plateaus. In these
two broad belts the bird-watcher may expect to see from 1 to 10
birds per hour afield during a full day's quest. They warn,
however, that the Texas-New Mexico area of concentration may be
the result of the oasis-like nature of suitable habitat, and the
special attention this receives from the bird counters. According
to their analysis of banded bird data, only the eastern race of
the white-crown is regular east of the 90o
parallel. Between 90o and 105o
(the Great Plains region) the eastern and Gambel's races migrate
and winter together. Intergrades from the west side of Hudson Bay
winter mostly in the Dakotas.
The eastern white-crown has apparently been extending its
winter range both eastward and northward since about 1950. A very
few now winter fairly regularly as far northeast as the New York
City region (John Bull, 1964), where winter reports were hardly
credible 20 years earlier (Cruickshank, 1942), and quite unknown
when Ludlow Griscom (1923) summed up the status of that region's
bird life. The climatic amelioration of the first half of the
century may have facilitated this range expansion, but such new
land-use practices as the planting of multiflora (Rosa
multiflora) hedges and the great number of bird-feeding
stations that have come into vogue during this period have
unquestionably helped tide over individual birds.
White-crowned Sparrow*
Zonotrichia leucophrys
[Eastern White-crowned Sparrow]
Contributed by Roland C.
Clement
*Original Source: Bent,
Arthur Cleveland and collaborators (compiled and edited by Oliver
L. Austin, Jr.). 1968. Smithsonian Institution United States
National Museum Bulletin 237 (Part 3): 1273-1291. United States
Government Printing Office
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