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A
chapter from the electronic book:
Life Histories of Familiar North American
Birds
Brown
Thrasher
Toxostoma rufum
[Published
in 1948: Smithsonian Institution United States National Museum
Bulletin 195: 351-374]
*** During some 60 years of acquaintance with the brown
thrasher in eastern Massachusetts, I have formed a somewhat
different impression of it from that gathered from the published
accounts of it in more western and southern regions. Ever since I
was a small boy, the catbird has lived and raised its young in my
father's yard, and more recently in my own yard, every year, and
this close to the center of the city of Taunton, almost within a
stone's throw of brick and mortar. But the thrasher never has
nested here, and only on rare occasions have I seen a straggler in
my yard. Any my experience has been similar to that of other
observers. Here the thrasher is essentially a bird of the rural,
woodland, and farming districts, living in bushy pastures,
sproutlands, brier patches, tangles along fences, dry thickets,
brushy hillsides, and the edges of woodlands, almost always far
from human habitations. On large estates and in parks or
reservations, where there are scattered woodlands and plenty of
shrubbery, the brown thrasher may find a congenial home, and here
it may build its nest close to a house; but such cases are
exceptional in New England, so far as I can learn; as a rule, our
thrashers are shy, retiring birds of the more open countryside.
Miss Sherman (1912) writes:
In eastern Massachusetts it is said to be a nesting bird of
the woodlands, rarely coming close to the homes of men to build
its nest. This may in part be due to the pruned, trimmed and
shaven condition of trees, shrubs and lawns. I remember once
seeing a pair nesting in a hedge quite near a house at Quaker Hill
in eastern New York. It is a bird that seeks a bit of thick and
tangled growth in which to build, but in Iowa it finds such places
to its taste in the man-planted trees and shrubs that grow upon
prairie soil, usually not far from human homes. It is eminently a
house-yard bird, although it sometimes nests in patches of bushy
second growth that have sprung up on clearings made in the woods.
Dr. W. G. Erwin (1935) made his extensive studies of the brown
thrasher on the campus of George Peabody College for Teachers, in
Nashville, Tenn., where several pairs nested near the buildings
and in the shrubbery, in spite of much human activity. At
Fairmount Hill, a suburb of Wichita, Kans., Dwight Isely (1912)
found this bird "in large numbers all over the city, and in
the parks. Its nests are very abundant in osage orange hedges. In
May and June the old birds, followed by the young, may be seen on
the lawns everywhere, pulling worms out of the ground. They feed
also in the fields and a few follow the plow." And, in Kansas
City, Mo., according to Harry Harris (1919), "they breed
freely within the city in the same districts and in the same kind
of brushy cover as the Catbird. The two species do not nest close
together, however, as they are mortal enemies during the breeding
season and have been known to battle to death over a disputed
nesting site." Similar habitats are frequented in other
western and southern states, which are quite different from our
conception of the haunts of the brown thrasher in New England;
perhaps, if we had more neglected brush heaps and tangles of
unkempt shrubbery and vines about our grounds, we might tempt the
thrasher to be
more sociable and nest near our homes.
Spring.--Many of the early spring
birds, the bluebird, the robin, the phoebe, the grackle, and
others, have come to Massachusetts during March and the early
April days; they have advanced and they have retreated as gentle
spring struggled to overcome relentless winter; but, during the
last 10 days of April, when the pussy willows are decorated with
golden tassels, the swamp maples are glowing with bright red
blossoms, and the shadbush and the cherry trees are in full bloom,
it seems as if spring had really come, with nature awakening all
about us. Then we may look for the coming of the brown thrasher.
As we walk along some country road on a bright spring morning,
warmed by the rising sun and the soft south wind, we may see him
perched in the top of some wayside tree or on some tall bush on
the border of the woods, pouring out his delightful song, with his
head held high, his bill wide open, his long tail drooping, and
his whole frame vibrating with the ecstasy of his song. We may
imagine that he is telling the farmer in the adjacent plowed lot
how to plant his corn; at least, his words seem to say so; but,
more likely, it is just an outburst of joy, to announce that he
has found his summer home, a warning to any rival that he claims
his territory, or an invitation to an expected mate to come and
join him in his homemaking. What a thrill of springtime pleasure
such a scene must give to the appreciative mind! I pity the sordid
soul that can pass it by unheeded, for he misses much of the
beauty in the world about him.
Territory.--Each pair of
thrashers has a definite breeding territory, which it defends
during the nesting season. The male arrives some days in advance
of the female and begins at once to look the region over with a
view to selecting his territory; at first he is furtive and quiet
but soon announces his choice in his loud outburst of song, an
invitation to his mate. The actual nesting site, probably selected
by the female, may or may not be very near the singing tree.
Aretas A. Saunders writes to me: "In the spring of 1923 I
noted during early morning walks that a brown thrasher sang daily
from a small tree along a roadside in Fairfield, Conn. The bird
sang from April 27 to May 13. On the 14th, not hearing the song at
first, I soon discovered the bird in a tangle of weeds and
blackberry almost directly beneath the singing tree. Another bird,
evidently the female, was with him and he was following her around
on the ground, singing constantly a song like the normal one in
form but so faint I could not have heard it had I not been very
close to the birds. After that time I no longer heard this bird in
song and did not see it or its mate again until May 22, when I
discovered the nest with four eggs and a bird incubating them. The
nest was in almost the exact spot where I had observed the
courtship and almost directly beneath the singing tree of late
April and early May."
Another experience of his was quite different. On a small hill
near his house was a dense thicket of sumacs, rambler roses, and
other shrubs, in which for a succession of years a pair of song
sparrows and later a pair of catbirds had nested. "The
catbirds nested there until 1938. That spring the male catbird
arrived and sang as usual, and a week or so later his mate
arrived. On May 18, when the catbirds were just beginning to
gather nesting material, a pair of brown thrashers arrived rather
suddenly; they at once took over the thicket and started
nest-building. I saw no fighting between them and the catbirds.
The latter simply retired to a neighboring yard.
"I had heard no thrasher song anywhere near my home, and I
did not hear it now. The birds had simply moved in from elsewhere
after they had become mated. The nest was soon finished and the
eggs laid. During the period of incubation, I heard the male
thrasher sing a few notes one day, but that was all the song I
heard from the bird that summer. They produced a brood of young
successfully.
"I believe that both the brown thrasher and the catbird
are territorial in nesting behavior. But in this region the
catbird is extremely abundant and the thrasher only fairly common.
For catbirds territory is scarce, but for thrashers it is
abundant. Evidently a pair of thrashers can have their pick of
territory, once they are mated, by simply taking that of the
catbirds. So they often move elsewhere after the mate arrives,
whereas catbirds must stick to the territory they have selected.
"So, it seems from this observation that the male thrasher
does not always select the nesting territory, but merely one to
which it first attracts a mate by its singing. The nesting
territory, in some cases at least, is selected after the mating
has taken place, and then it would seem likely that the female
would have more to do with the selection than her mate."
From Dr. Erwin's (1935) studies of the territorial behavior of
the brown thrasher on Peabody College campus, "it seems that
the male Thrasher selects a desirable area immediately after
arrival, and remains in this area for 10 or more days before
beginning his song. The author was unable to secure data which
would indicate whether territorial fights occurred within this
interval or not." He continues:
An effort was made to locate the boundaries of the
territories of each pair of Thrashers on Peabody Campus. The
method used was the observation of the limits of their feeding
grounds and the locations and results of territorial fights. . . .
There seemed to be a definite tendency for the Thrashers to adopt
buildings, driveways, walks, and shrubbery rows for boundaries in
many cases. After a territory was established, the activities of
the particular pair of Thrashers seemed to be almost entirely
confined to this area. All nests of the season were built within
this territory. . . .
Thrashers almost always object to the presence of other
Thrashers in their territory, although they usually do not object
to the presence of birds of other species so long as they do not
go near their nest, or do not interfere with their feeding
activities.
Courtship.--The loud, tree-top
song of the male is the first step in the courtship performance,
the curtain raiser, as it were. It will be noted from the above
account that the male does not begin to sing immediately on his
arrival but waits until he can expect the arrival of a possible
mate, a matter of perhaps 10 days or 2 weeks. Then he issues his
loud invitation, which, under favorable circumstances, may be
heard at a long distance. This song is also a challenge to rival
males, and territorial fights between the rivals may occur during
the early stages of courtship. When the male and the female
finally come together, the song of the male becomes so subdued and
soft that it is almost inaudible, as the pair play about close
together under the shrubbery. Dr. Erwin's (1935) records show that
the male "sang very softly when the female was nearby, but
when she flew away he also [as did another] began to sing much
louder, as if to call her back, and at one time followed her a
short distance, singing on the wing."
The more intimate part of the courtship is not easily seen, as
it usually takes place under dense cover, but Dr. Erwin has
published the following account of it in his excellent paper:
April 29, 9:00 a.m., both male and female were observed
under the shrubbery at the right of the exit. The female hopped
out in the grass away from the shrubbery about 10 feet and began
to dig in the ground with her bill. After about 5 minutes the male
came out a distance of about a foot from the shrubbery. The female
picked up a small twig in her bill and hopped back to the male,
fluttering her wings vigorously, giving soft chirps. No further
activities were observed as they searched for food among the
leaves for 8 minutes. Then the female hopped out on the grass,
again secured a twig, and began to flutter her wings and give soft
chirps as before. The male picked up two dead leaves and hopped
toward her, whereupon she fluttered her wings even more vigorously
and issued chirps a little louder. Both dropped the materials held
in their bills and engaged in coitus. Both birds then hopped down
the shrubbery row, the female gathering twigs and fluttering her
wings several times, after which both went under the shrubbery.
He did not see any show of display or strutting in this or
other courtship antics. Audubon (1841b), however, says: "The
actions of this species during the period of courtship are very
curious, the male often strutting before the female with his tail
trailing on the ground, moving gracefully round her, in the manner
of some pigeons, and while perched and singing in her presence,
vibrating his body with vehemence."
Brown thrashers do not always remain mated through even one
breeding season. Samuel Elliott Perkins, 3d (1930), has shown this
to be so in at least some cases by banding and recovering adult
thrashers during the rearing of their first and second broods. He
reports "a case of a pair of birds changing mates 2 months
after they had raised a brood together, under conditions which
proved that it was not the seeking of a new mate after the death
of the previous one." In this case, each of the original pair
was trapped and found to be paired with a new mate. He continues:
"We have had four other pairs of Brown Thrashers in the same
area under observation, where only one of each pair was a banded
bird. The inference seems irresistible that after each brood is
raised there is a complete shuffling of mates among the Brown
Thrashers." Apparently the brown thrasher is no more constant
in its marital relations than is the house wren. Arthur T. Wayne
(1910) was told by a man he considered to be reliable of a female
brown thrasher being mated with a male mockingbird.
Nesting.--I have been surprised to
read in the literature and in contributed notes that, throughout
the western and southern portions of its range, the brown thrasher
very seldom builds its nest upon the ground, for that is certainly
not the case in New England, or at least in eastern Massachusetts.
Miss Sherman (1912) writes:
In Iowa I have never found a nest nearer than 18 inches or 2
feet of the ground, one of these being in the lower branches of a
spruce tree, the other in a brush pile. Another was found built in
a brush pile, but farther from the ground; these are the only
nests thus situated that have been found, but brush piles on
prairie land are rare. The next locations nearest the ground are
where nests are built in such bushes as gooseberry, lilac, and
syringa, when they are from two to three feet above the ground.
The highest nest situation found was one in a tame crabapple tree
about ten feet up; the other trees frequently used are spruce,
willow, apple, and plum trees in which a majority of the nests are
about five feet from the ground.
A. Dawes DuBois has sent me his data on 19 nests, found in
Illinois, only one of which was on the ground "under a large,
cattle-eaten bush in a pasture"; he remarks that this is the
only nest he ever found on the ground. His other nests were mostly
in bushes, hedges, or low trees; one was 3 feet from the ground in
a large osage-orange hedge, and one was in the top of an apple
tree.
Frank W. Braund's data sent to me show five nests, found in
Ohio, all 2 1/2 to 4 feet up in bushes or small trees. One nest
found near Jackson, Tenn., but not collected, was of rather
unusual construction, begin made of coarse grasses, with a few
leaves, and lined with fine grass.
There is a set of six eggs in my collection, taken by W. L.
Griffin in Pulaski County, Ky., that came from a nest 15 feet from
the ground in a gum tree; the eggs were evidently laid by two
females, as two of them were more heavily marked than the other
four; furthermore, three adult birds appeared and made the usual
demonstration while the eggs were being taken.
Evidently none of the nests studied by Dr. Erwin (1935) at
Nashville, Tenn., was on the ground; his lowest nest was a foot
from the ground in a thick growth of smilax; one pair of thrashers
started a nest 14 feet up on a horizontal branch of a maple but
never completed it. Of the 59 nests examined, nearly 80 percent
were between 2 and 7 feet above ground; only nine were higher and
three lower. "The most common locations for nests on Peabody
Campus were Golden Bell (Forsythia sp.) and Privet (Ligustrum
sp.). Other shrubs and smaller trees were occasionally used."
W. Leon Dawson (1903), referring to Ohio, writes: "Nesting
sites are various, but the bird shows a decided preference for
those which are naturally defended by thorns. Nearly every full
sized Crategus (thorn apple) has at one time harbored a nest.
Hedges of osage-orange are well patronized--almost exclusively so.
. . further west--and the honey-locust tree is not forgotten. Next
after these come wild plum thickets, grapevine tangles, brush
heaps, fence corners, and last of all, the ground." He shows
a photograph of a nest in a corner of a Virginia rail fence.
H. O. Todd, Jr., tells me that out of 109 nests found in
Tennessee, only one was on the ground.
It is rather unusual for a thrasher to build its nest close to
a house, but several such cases have been reported; E. S. Cameron
(1908) reports a nest built close to a window in his house on his
ranch in Montana; and E. D. Nauman (1930a) writes: "While
myself and family were living on a farm near Thornburg, Iowa, some
years ago, we had a thriving rose bush standing directly in front
of the kitchen window and close up; so close in fact that some of
the foliage and roses touched the glass. One season the Brown
Thrashers (Toxostoma rufum) made their home in the rose
bush. Their nest was twenty inches from the window glass."
The birds were not in the least disturbed by activities within the
house. The only report I can find of any considerable number of
brown thrasher nests on the ground in the Middle West comes from
Edmonde S. Currier (1904) in Minnesota. He says: "Several
nests seen, and all of them were sunken in the ground after
the manner of a Towhee's. In Iowa I have seen the nest thus
placed, but it is very unusual, and it is strange that the Leech
Lake bird should prefer such a situation, though there must be a
reason."
On the contrary, ground nests are common in New England. One
half of the nests in southeastern Massachusetts, as recorded in my
field notes, were on the ground under bushes, trees, or thickets.
The others were in bushes, small trees, or brush heaps; the
highest nest I find recorded was only 4 feet from the ground in an
arborvitae. Frederick H. Kennard's notes for the vicinity of
Boston record 23 nests, 10 of which were on the ground. All
authorities seem to agree that, in this region, ground nests are
of common occurrence, especially on the higher lands, where the
ground is warm and dry and where the thrasher evidently prefers to
nest.
Eggs of the brown thrasher have been found in the nests of
other birds. There is a set of eggs in the American Museum of
Natural History, in New York, taken by H. B. Bailey on June 5,
1886, near South Orange, N.J. It was taken from a wood thrush's
nest, which contained four eggs of the thrush, incubated about 7
days, and two fresh eggs of the thrasher. Thrasher eggs have also
been found in nests with those of the mockingbird, the robin, and
the cardinal. Dr. W. C. Herman (1923) tells of a remarkable dual
nest, in which "the foundation was typical of that of the
thrasher, while the center was that of the robin, both nests being
well made and complete in every detail. His photograph of it shows
four eggs of the thrasher and one of the robin. The thrasher was
on the nest, which was afterward destroyed by some unknown enemy.
E. D. Nauman (1930b) found a thrasher incubating on its nest, with
two of its own eggs and two of the cardinal under it. The
cardinal's eggs were evidently deposited about a week after
incubation had begun on the thrasher's eggs, for the next time he
visited the nest it contained two young thrashers and two eggs of
the cardinal, on which the latter bird was incubating. This nest
also came to grief.
Dr. Erwin (1935) gives a very full account of the building of
the nest, in which both birds take part, and a good description of
the composition of the nest:
The later nests were more poorly constructed than the
earlier ones. Five to seven days were usually required for the
construction of the earlier nests, while only three to four days
were required for the later ones. It also seemed that the type of
location of the nest had something to do with the amount of
materials used.
Twenty-three nests were carefully examined to discover the
architecture and materials of construction. The nests were
composed of four concentric layers, or baskets. The first basket
was composed entirely of twigs, usually from four to twelve inches
long and from 1/16 to 1/4 of an inch in diameter. The second
basket was composed principally of dead leaves. A few pieces of
paper, thin bark, and tiny twigs were sometimes used. The third
basket was composed of tiny twigs and grass stems. In a few of the
later nests this basket was almost completely lacking. The fourth
basket, or lining, was usually composed of well-cleaned rootlets,
mostly from grasses. In a few cases petioles of the Honey Locust
were used exclusively.
He gives an account of the building operations in too great
detail to be quoted here. The birds had considerable difficulty in
carrying the twigs through the thickly entwined branches of the
shrubbery; often the twigs were left hanging where they were
caught, and sometimes they were recovered but sometimes not. When
the female apparently discovered a desirable place, "with her
bill she pushed the twigs closer together, then got on the thickly
matted stems and began the movements in which many birds engage
during nest building. She intermittently lowered her head, relaxed
her wings, and with rapid jerks shifted her feet sidewise."
This method of nest-shaping was continued with each of the
successive layers. At one nest he noted that the female made 28
and the male 21 trips to the nest between 2:45 and 4:40 p.m.
Soon after the young have left the first nest, the female
starts building a second nest, leaving the male to care for the
first brood of young. At one nest the young left the nest on May
5, and on May 10 the female was discovered putting the lining into
the second nest. Another female was seen completing a second nest
11 days after the young had left the first nest. Mr. Saunders
tells me that a pair that he watched "produced a brood of
young successfully, which left the nest on June 15. On June 17
they began a second nest. Incubation of the second set began on
June 24."
Nesting sites in the South are apparently similar to those in
the Midwest--hedges, shrubbery, brush heaps, thickets, grapevine
tangles, vines, and trees. A. H. Howell (1932) states that
"Nicholson found a number of nests at Orlando [Florida] in
oak and orange trees, 8 to 20 feet above the ground."
Frederick V. Hebard mentions in his notes from southeastern
Georgia a nest in a "sea-myrtle bush about 20 inches above
ground. This nest was badly constructed of dried grass supported
by twigs, one of which was over 14 inches long. Corn husks were in
the nest. The nest had an inside diameter of 3 3/4 inches, an
inside depth of seven-eighths inch, and an outside depth of 3 3/4
inches." Another nest was in a camphor tree, 7 feet above
ground.
Eggs.--Nearly all the nests of the
brown thrasher of which I have record contained either 4 or 5
eggs, generally 4; the one set of 6 eggs in my collection was
evidently the product of 2 females. Eggs were laid in 52 of the
nests examined by Dr. Erwin (1935) in Tennessee; 31 contained 4
eggs, 13 contained 3 eggs, 7 contained 5 eggs, and one contained
only 2 eggs. Six eggs have been recorded.
The eggs are not handsome, but they show considerable variation
in color and shape; they are usually ovate, but some are somewhat
elongated and some are short-ovate. The ground color is very pale
blue, bluish white, or white, with sometimes a greenish tinge.
They are usually rather evenly covered, more or less thickly, with
very small spots or fine dots of reddish brown or duller browns.
Sometimes the markings are so small, scarce, and faint as to make
the egg appear almost white. Very rarely a set of eggs is
immaculate. Occasionally the markings are grouped in a ring around
one end. A rare and handsome type has a darker green ground color,
with bright reddish spots.
The measurements of 50 eggs in the United States National
Museum average 26.5 by 19.4 millimeters; the eggs showing the four
extremes measure 30.2 by 19.8, 26.7 by 21.3, and 21.3
by 16.3 millimeters.
Young.--The period of incubation
is stated by several observers to vary from 11 to 14 days,
according to weather temperatures and other conditions. Dr. Erwin
(1935) says: "Of the 32 nests in which eggs were laid on
Peabody Campus, only 17 were successfully incubated. Nine of these
required a period of 13 days, six 12 days, one 11 days, and one 14
days. The set of eggs which required 14 days was in an early
nest." Both sexes shared the duties of incubation. During a
period of 14 hours 15 minutes, the female incubated 9 hours 11
minutes; and the male sat 3 hours 51 minutes, about 27 percent of
the total time, perhaps to give the female a chance to feed.
"For 12 successful nests on Peabody Campus, the average
nestling period was 11 days. Two of the nests had young with a
nestling period of 13 days. Both of these nests were early. The
nestling period for one nest was 12 days, for four 11 days, for
four, 10 days, and for one, 9 days."
He noted that both parents helped to feed the young in the
nests. A total of 8 hours 6 minutes on parts of five days was
spent in observation of the feeding process at two nests. He says:
During this period, the different females made a total of 40
trips to the nest with food, and the males, 31 trips. This food
consisted almost entirely of white grubs, soft caterpillars, and
earth worms. A small part of the time was spent in brooding, this
duty being shared by both male and female. Most of the periods of
brooding occurred in the early morning when the weather was cool
and the young still were without a full coating of feathers. On
one occasion the female, being unable to cover the five young,
used her bill to pull them toward her. Both male and female always
inspected the nest for excreta before going on to brood. Excretion
always occurred immediately after the nestling, or nestlings, were
fed. The excreta was encased in a transparent bag, which prevented
it from soiling the nest while being removed. The excreta from the
very young birds was almost always eaten, while that from the
older nestlings was usually carried away and dropped. . . .
In cases where a second nest was built after young were
successfully brought off the preceding nest, the female remained
to help care for the young only a few days, after which she built
the second nest without assistance of the male, his duty being to
care for the nestlings. There were only two nests in which this
occurred during the year. The other nestlings were brought off too
late, due to previous failures, for the adults to build another
nest. In two instances where the female did not build another nest
after the young were brought off, the young were divided, the male
taking a part of the young, and the female the remainder. Also in
these two instances, the territory was also divided. . . . After
the first brood of young became independent, it seemed that the
male returned to assist the female in care of the second brood.
Dr. Ira N. Gabrielson (1912) made a careful study of a brood of
young brown thrashers in Iowa; the nest was on the ground, which
he remarked was unusual; when it was discovered, on June 17, it
held four young, "not more than 24 hours old," and an
addled egg; a blind was set up near the nest and observations
began on June 23 and continued until the young left the nest on
June 28. He says:
[On June 23] the afternoon was hot and sultry and the nest
was in such a position as to be exposed to the hot rays of the
sun. One or the other of the old birds brooded almost all of the
time. During the afternoon, the male brooded once for a period of
26 minutes and the female for 20 minutes, but the periods as a
rule were short, being from 2 to 5 minutes in length. At about 2
o'clock the shadow of an oak tree was thrown on the nest and the
old birds ceased brooding. . . . There was a marked difference in
the position assumed by the male and female in brooding. The male
sat on the edge of the nest with his feathers ruffled up, or stood
in the nest in much the same posture, affording very poor
protection for the young as compared with that given by the
female. She spread her wings, ruffled her feathers, and stood in
such a position as to completely shade the nest.
He made a careful record of the food given to the young and
published a long list of insects, larvae, spiders, and worms
supplied. "The four insects consumed in the largest
quantities were found to be as follows: grasshoppers 247, Mayflies
425, moths 237, and cutworms 103. Two of these, at least, are
positively destructive insects; and in the summer of 1911 the
grasshoppers were almost a plague in parts of northern Iowa. Many
fields of grain were destroyed and many more were cut green to
prevent destruction, making the oats light weight and poor
quality. The grasshoppers stripped the oats from the straw by
cutting the stem of each grain. This was done while the grain was
in the milk, so it was a total loss."
A record was kept of the number of feedings by each parent each
day; the longest and largest record was made on June 27; from 3:30
a.m. to 9:00 p.m. the male fed the young 98 times and the female
fed them 186 times, or a total of 286 feedings, including twice
that the young were fed without the sex of the parent being known.
In order to determine the quantity of food received by each
nestling, the young birds were marked with green, orange, blue,
and white thread. "From June 26 at 4:11 p.m., until Green
left the nest on the 28th, at 12:19 p.m., he was fed 152 times;
Orange 142 times; White 169 times; and Blue 133 times. Orange was
a small and active bird; White was large and inactive, but
seemingly possessed plenty of strength; Blue was weak and
timid." The total amount distributed during this time, parts
of 3 days, was 976 insects, or an average of 219 to each young
bird. Gabrielson continues:
Sometimes it seemed as if chance determined which individual
would receive the morsel, and at other times looked as if there
were other factors. There seemed to be a tendency to feed the one
nearest the parent bird, and, as the old birds almost invariably
approached the nest from the south, it would follow that the
nestling on that side would get the most food. However that may
be, the young were constantly trying to get to that side of the
nest. One would no sooner get into place on that side than another
would crowd him out. This was not always the case, for at times
the parents would reach over and feed those on the farther side.
Again it seemed as if the nestling that made the greatest
disturbance received the food.
The nest was kept scrupulously clean through the efforts of
both parents; on June 27, from 3:30 a.m. to 9:00 p.m., the nest
was cleaned 18 times by the male and 38 times by the female.
Three interesting facts were noted in connection with the
passage of the excreta: viz., the young birds made no attempt to
void the excreta except when one of the parent birds was present;
second, only one of the nestlings voided the excreta at any one
visit of the parent birds; and third, almost always the bird fed,
or if two were fed, one of the two voided the excreta. . . . The
results of these observations seem to indicate that the feeding
may possibly be the direct stimulus to the voiding of the excreta,
as out of a possible 112 times 104 sacs of excreta were removed
from the nestling receiving the food at that visit, while only
eight were removed from different birds. The parents always
stopped a few seconds after feeding, possibly waiting for the
appearance of an excreta sac. In the case of the nestling voiding
the excreta, there were usually some premonitory signs: viz.,
general uneasiness, ruffling the feathers, and flirting the tail.
Then followed the elevating of the posterior end of the body, and
as the sac came away the parent bird seized it and either devoured
it or carried it away. . . . It would seem. . .that about the
eighth or ninth day the old birds ceased devouring the excreta and
commenced to carry it away. . . .
At about noon, June 28, the young birds became very
restless, especially Green and Orange. They were continually
crawling out of the nest and back again. At 12:30 p.m. Green
crawled out of the nest and sat chirping for a short time. He then
spread his wings and made an attempt to fly, but only succeeded in
going a few inches. Immediately on falling he commenced to hop
rapidly away; stopping a short interval at a fence about 10 feet
distant. One of the old birds returned at this time and coaxed him
along until he reached the top of a little hill some 60 yards
away. . . . At 2:10, Orange left the nest in much the same way.
The male went with him and by coaxing him a short way at a time
soon had the second nestling on the little knoll occupied by
Green. The male busied himself the rest of the day caring for
these two while the female fed White and Blue in the nest.
The next morning White started away at 7:07 and was coaxed
along by the female for about 30 yards. Blue remained alone in the
nest until 7:45, being fed only once in the interval, though White
was fed three times. 7:45 Blue left the nest, but no parent bird
returned to aid in the journey as long as the observations were
continued. At 8:15, when the observations ceased, Blue was still
alone in the grass. Later all four fledglings were found in the
ravine nearby. They were noticed here several times, July 25 being
the latest date on which they were positively identified.
Amelia R. Laskey tells me that "a fledgling fed by hand,
but given freedom, was noted singing a very soft song on July 24,
when 44 days old. This song was similar to the autumn singing
heard each year in August and September in the garden."
A. L. Pickens sends me the following note on the method used by
a thrasher in coaxing its young from the nest: "The young had
been hatched in a rose vine at the edge of our front porch and
were at that stage where they could clamber out of the nest and
perch in the surrounding vines. They could not fly, but the old
bird seemed anxious to have them leave a spot so frequently
examined by human eyes. Coaxing having failed, the parent resorted
to strategy. She came to the nest with a small piece of paper so
folded and compressed together as to resemble, especially in size,
the morsels of food usually brought to the young. This she held
temptingly first above one young one's mouth, then above
another's. But as the young beaks were expectantly extended she
raised or withdrew the bogus morsel still farther away. Then she
flew away to a short distance still temptingly holding the bit of
paper. At last one of her offspring, fluttering and clambering,
dropped to the ground, and she began leading it along a route that
led through the yard and grove, evidently to the denser growth of
a small wood nearby. Fearing for the young's safety I captured it
and brought it back to the nest amid angry protests from the
parent. In this outburst she dropped her imitation morsel, and I
took particular pains to carefully retrieve and examine it."
Plumages.--I have not seen any
young brown thrashers in natal down. The juvenal plumage is softer
and looser, less compact, and easily recognized. It resembles the
adult plumage in pattern but is paler and duller throughout; the
top of the head is darker and the rump lighter, and all of the
upper surface is more or less streaked or spotted with dusky; the
wing bars are buffy, and the tertials are edged and tipped with
buffy; the underparts are dull white, the streaks and spots being
more numerous and less sharply defined. The iris in the young bird
is gray.
A postjuvenal molt occurs in late summer or early fall,
beginning the last of July, and involving the contour plumage and
most of the wing coverts, but not the rest of the wings or the
tail. This produces a first winter plumage, which is practically
indistinguishable from that of the adult at the same season.
Adults have one complete annual molt, the postnuptial, in July
and August. In fresh fall plumage the colors are darker and richer
than they are in spring, the upper surface being deep cinnamon-rufous,
and on the lower surface the throat, sides, and crissum are washed
with ochraceous-buff; the wing coverts are cinnamon-rufous, and
the wing bands are buffy white. There is no evidence of a spring
molt, but wear and fading are considerable, the buffy shades
disappearing and the whole plumage becoming more or less ragged
before midsummer. The sexes are alike in all plumages.
Food.--E. H. Forbush (1929) gives a
very good account of the food of the brown thrasher, based largely
on Prof. Beal's (Beal, McAtee, and Kalmbach, 1916) report:
An examination of 266 stomachs of the bird from various
parts of the country was made by Prof. F. E. L. Beal of the
Biological Survey, and it showed that the food consisted of 37.38
percent vegetable and 62.62 percent animal food, the latter nearly
all insects. The insect food was rather evenly divided among the
various orders. Beetles were eaten regularly the year round. Such
pests as May beetles, white grubs, twelve-spotted cucumber
beetles, many weevils, including the cotton-boll weevil,
curculios, snap-beetles and wire-worms, rose-beetles,
strawberry-crown girdlers and wood-boring beetles, caterpillars,
including canker-worms, army-worms, cut-worms and hairy
caterpillars such as the tent and gipsy caterpillars, also bugs of
many kinds, especially those that eat berries, also leaf-hoppers,
tree-hoppers and cicadas, quantities of grasshoppers and locusts
and many crickets are eaten, also many of the ants that destroy
timber. A small proportion of beneficial ground-beetles are taken,
and very few wasps and bees; daddy-long-legs, sow-bugs, small
batrachians, lizards and snakes are taken more or less.
Professor Beal (Beal, McAtee, and Kalmbach, 1916) says that
beetles form the largest item in the thrasher's food, 18.14
percent; caterpillars come next, 5.95 percent; other insects are
eaten in much smaller quantities, as are also spiders, myriapods,
crawfish, snails, and angleworms. "Bones of lizards,
salamanders, and tree frogs (in all, 0.92 percent) were found in
11 stomachs." He gives the thrasher credit for destroying
only 2.43 percent of the grasshoppers and crickets for the year,
with a maximum of 8.5 percent in September, whereas Dr. Gabrielson
(1912) says that, at the time of his study in Iowa, 20 percent of
the food of old and young thrashers consisted of grasshoppers.
On the vegetable food, Professor Beal (1916) writes:
The vegetable food of this bird is nearly equally divided
between fruit and a number of other substances, of which mast is
the most prominent. Wild fruit, the largest item in the vegetable
portion (19.94 percent), was eaten every month in varying
quantities, the month of maximum consumption (45.69 percent) being
September; January and February, with dried-up fruit from the last
summer's crop, stand next. Altogether about 30 species of wild
fruits or berries were identified in the stomachs. Those most
eaten are blueberries, huckleberries, holly berries, elderberries,
pokeberries, hackberries, Virginia creeper, and sour gum. Some
seeds not properly classified as "fruit" were found, as
bayberry, sumac--including some of the poisonous species--pine,
and sweet gum.
Domestic fruit, or what was called such, was found in nine
months, from April to the end of the year, most of it (53.19
percent) in July. Raspberries or blackberries, currants, grapes,
cherries, and strawberries were positively identified by their
seeds, but as all of these grow wild, it is probable that much
that is conventionally termed domestic fruit is really from
uncultivated plants. The aggregate for the year is 12.42 percent.
Mast, principally acorns, was estimated at 23.72 percent for
the year, and grain only 2.57 percent. "The grain was nearly
all corn, with a little wheat, but from the season in which it was
taken most of it evidently was waste." The thrasher has been
accused of pulling up planted corn, but this is probably local and
restricted to a few individual birds.
W. L. McAtee (1926a) mentions some additional insects, eaten by
the thrasher, that are injurious to wood lots, such as nut
weevils, the wild cherry-leave weevil (Epicaerus imbricatus),
oak weevil (Eupsalis minuta), and the yellow-necked
caterpillar (Datana ministra); and, also to the above
lists, he adds the Japanese beetle, clover-root weevil, billbugs,
and the chinch bug, as of more interest to the agriculturalist.
The brown thrasher spends most of its time on or near the
ground and obtains the greater part of its food there. One may
often be seen foraging among the fallen leaves on the ground under
trees or shrubs, or in more open spaces. It apparently seldom
scratches for its food, as do the fox sparrow and the towhee, but
uses its long, strong bill much as a haymaker uses a pitchfork in
spreading hay; thus, with powerful sidewise strokes, it sends the
leaves flying in all directions, and then stops to pick up what
desirable morsels it finds beneath them. In this way it works
diligently over considerable ground, occasionally picking up a
leaf to cast it aside but more often pitching them away with its
closed bill. Some writers have suggested that his name may have
come from this habit of thrashing about among the leaves and
rubbish; another suggestion is that his habit of thrashing large
insects or other prey on the hard ground to kill or mutilate them
has suggested the name; a still more fanciful notion came from
someone who had been thrashed by the bird in defense of its nest.
Milton P. Skinner (1928) writes of its feeding habits in North
Carolina:
One was seen that picked the ground for a time and then
alternated its picking strokes with some sidewise scoops of its
bill. Later it ran swiftly along for 6 feet and caught an insect
that was flying low. Another Thrasher was seen making
flycatcher-like sallies from the ground, and later from well up in
an oak. They sometimes chase lively, erratic insects through the
grass, and at other times adopt the Flicker method of digging down
a good inch and a half into the sandy soil, probably for grubs.
Brown Thrashers sometimes pick up acorns and carry them away in
their bills, and later open them as the Jays do. But they are
ground birds, unlike the Jays, and when they try to split the
shell from an acorn by pile-driver blows, they often drive the
acorn down into the soft ground. In spite of this difficulty, they
persevere and the shell eventually flies off. I have seen one eat
a shelled acorn in a few bites. Apparently, acorns are an
essential part of their winter food.
He says that thrashers "occasionally fly up on the weed
stalks and pluck the seeds direct" and also that they are
very fond of sumac berries; one "ate for some minutes, quite
stripping the head of all fruit; then rested a few minutes before
eating another score of the berries." He adds that they
sometimes eat persimmons and smilax berries but found that sumac
berries were a favorite food in December.
Behavior.--As suggested by Miss
Sherman (1912) and as mentioned in the first part of this account,
there seems to be some variation in the general behavior and in
the disposition of the brown thrasher in New England from what has
been noted in the Midwest and South. In Massachusetts I have
always regarded it as a shy, retiring, and somewhat unfriendly
bird, shunning human society and especially hostile to the
intruder near its nest. In other parts of the country, it seems to
be more sociable, more friendly, and more inclined to make its
home in parks in towns and villages, or even cities, in gardens,
orchards, and close to human dwellings. These are not, however,
hard and fast rules, for there are exceptions in both cases.
The thrasher is one of the most valiant and aggressive
defenders of its nest and young among all our small birds,
exhibiting the greatest bravery and boldness. While the late
Herbert K. Job and I were photographing birds near West Haven,
Conn., on June 5, 1910, we found a thrasher brooding her young in
a nest 5 feet from the ground in a thick bush. She allowed Mr. Job
to stroke her on the nest before she left and then set up a loud
cry of protest and defiance, which soon brought her mate to join
in the attack. As I attempted to examine the young, both birds
flew at me and attacked me savagely; they flew at my face, once
striking a stinging blow close to my eye and drawing blood; within
a few seconds I was struck on the side of my head, and we decided
to withdraw from the scene of the battle, leaving the brave birds
masters of the situation. Mr. Job had had a similar experience
with fighting thrashers a few years previously; they attacked his
hands when he attempted to touch the young, and scratched and bit
holes through the skin.
Mrs. Amelia R. Laskey, of Nashville, Tenn., writes to me:
"Almost all brown thrashers show much concern when I look
into the nest or remove young for banding. Most of them scold or
squeal excruciatingly as if suffering intense pain. I have found
several individuals that were very pugnacious in attacking me and
very bold in their close approach. One bird struck the top of my
head with great force, apparently striking with both feet. Another
made a swift stab at my temple, striking with its beak with such
force as to draw blood. Another attacked the hand, removing and
replacing the young for banding purposes, with such venom that
drops of blood stood on several fingers from jabs made by its
beak."
Mr. DuBois tells me of one that attacked him, alighting on his
back and swooping down repeatedly to strike his hat. And there are
other reports of similar behavior toward human and other enemies.
Dr. B. H. Warren (1888) writes: "When their home is invaded
by a black snake, they assail such intruder in a most vigorous
manner. I once saw a dog, which had upset a nest containing young
Thrushes, forced to make a speedy retreat when attacked by the old
birds who flew at his head and struck him in the eyes." Dr.
T. M. Brewer wrote to him as follows:
I found a nest containing three eggs, which I removed,
leaving in their places three Robin's eggs, and retired to wait
the issue. In a few moments the female approached, gave the
contents of the nest a hasty survey, and immediately flew off. She
returned in a short time in company with her mate, and both flew
to the nest apparently in the greatest rage, took each an egg in
their claws, and dashed it against the ground at a distance
of more than a rod from the nest, the female repeating the same to
the other egg. This done, they continued for some time to vent
their rage on the broken eggs, tossing them about, and at the same
time manifesting their displeasure in every possible way. They
afterwards forsook the nest.
But not all thrashers are too shy, hostile, or vindictive. In
regions where they are closely associated with human activities,
notably in the Midwest, some individuals have become quite tame
and friendly, come freely to feeding stations, bathe in bird
baths, and have on rare occasions been induced to feed from human
hands (see Bird-Lore, vol. 10, p. 253, and vol. 20, p. 299).
Sidney E. Ekblaw (1918) reports the following interesting
experience:
It was in the latter half of June that the brown thrasher
first appeared at our home near Rantoul, Ill. My mother and sister
were at work on the back porch when the bird alighted on the
ground. Its apparent tameness attracted their attention, and when
it flew to a nearby fence-post my sister went out to it. When she
approached, the bird flew to her shoulder, where it stayed
contentedly for at least 3 minutes.
For 2 days it stayed about the place, not in the least
afraid, in no wise concerned about household activities carried on
about it. It allowed the various members of the family to pet it,
while it perched upon an arm or shoulder; it ate cherries that my
brother fed it, while he held it in his hand; and it showed not
the least objection to having its picture taken. The second day it
disappeared and we saw it no more.
The brown thrasher lives in the lower levels of the trees and
shrubbery, except when it mounts to the top of some outstanding
tree to sing its springtime challenge. It is especially at home
upon the ground, where it probably spends most of its time,
walking or running with short easy strides, or hopping about when
in no hurry. If necessary it can run quite fast to catch some
insect prey; or it can cover considerable ground with a series of
long high hops, where walking or running is not convenient. The
use of its strong bill to obtain its food is explained in the
section headed "Food."
Its flight is rather slow and, apparently, heavy; its short
wings are not adapted for swift or protracted flight; it usually
flies low and not for any great distances unless in crossing an
open field or a river. We often see the long, brown bird in the
middle of a country road, taking a dust bath in some dusty hollow,
or picking up the grain in scattered horse droppings; when thus
disturbed, it spreads its long, handsome tail, makes a short low
flight, and disappears in the roadside shrubbery or glides over
the top of a half-hidden stone wall and swoops down into cover. It
is equally at home in the thickets, running to cover when
approached and dodging skillfully through the brier tangles to
escape.
Mr. Skinner (1928) says: "They are very fond of bathing,
especially when the weather gets warm in spring. In earthenware
saucers, they will bathe when it is as cold as 55o
F., and when it is warmer they bathe regularly twice a day. But
they do not stop taking shower-baths just because artificial baths
are available. They are even out in steady rains, thoroughly
shaking themselves as the heavy raindrops soak their
plumage."
We do not know yet how long birds may live, as we have not been
banding birds long enough, or extensively enough, to be sure that
we have trapped the oldest bird. Several brown thrashers have been
reported as from 8 to 10 years old, but the oldest one seems to be
the bird reported by Miss Marion A. Boggs (1939) which, on the
eleventh return, was at least 13 years old.
Voice.--The brown thrasher is one of
our best and most spectacular singers; his loud, striking spring
song, once heard, can never be forgotten. Almost every writer on
American birds has commented on it and most favorably.
Dr. Winsor M. Tyler has given me his impression of it as
follows: "The song of the brown thrasher is a brilliant
performance, equaled, if judged solely by its technical skill, by
few North American birds, and surpassed by perhaps only one, the
mockingbird. Indeed, it is sometimes difficult to distinguish the
song of a thrasher, if an exceptionally fine singer, from that of
a mockingbird.
"The thrasher's song is made up of a long series of short,
sparkling phrases given rapidly, sometimes repeated two or three
times in quick succession, but as the song goes on it displays a
great variety of phrases. To sing, the thrasher mounts to a
conspicuous perch where, with the tail pointing to the ground, a
characteristic pose of the wrens while singing, he devotes himself
to his song, pouring out his loud, spirited concert, like a
vocalist singing a solo.
"In Massachusetts the thrasher sings from its arrival late
in April, with marked diminution during the nesting season, to the
first week in July. After this time it becomes silent and
inconspicuous, and we see it chiefly as a flash of cinnamon as it
retires into the shrubbery."
Dr. Charles W. Townsend (1924) writes the following
appreciative note on the thrasher's song:
The Brown Thrasher, a near relative of the Mockingbird, has
a more continuous song and, at its best, one of great beauty and
power not marred by harsh or disagreeable notes. His song consists
of a series of couplets with here and there an enthusiastic
triplet or even a quadruplet. It is an inventive song. He is
consistently improvising, but there is often the suggestion of
mimicry as the song wanders on and new phrases appear and are
repeated. It is rare, however, that one can recognize the source
of the mimicry. I have detected the call of the Bob-white and the
melody of the Robin, the Bobolink and the Veery, but mimicry is
not needed to complete the perfection of his song. He generally
avoids vulgar plagiarism, but doubtless profits by the musical
suggestions of other birds.
W. L. McAtee (1940b) says: "I was much interested in the
opportunity afforded me near Vienna, Va., in June 1940 to make
observations on the mimicking thrasher (Toxostoma rufum).
On a few occasions the song, beginning with imitations of some
shrill-noted species suggested that of a Mockingbird until it
lapsed into the gutturals and more deliberate phrasing
characteristic of the thrasher's music. The birds that were
imitated were all species commonly heard on the spot and included
the Flicker, Cardinal, Tufted Titmouse, Crested Flycatcher,
Yellow-breasted Chat, and Wood Thrush."
Aretas A. Saunders says: "The thrasher does not imitate
birds frequently, and I believe only a few individuals do so,
whereas many catbirds and practically all mockingbirds do so. I
have heard the thrasher imitate the phoebe, robin, wood thrush,
white-eyed vireo, red-winged blackbird, Baltimore oriole, vesper
sparrow, and field sparrow.
"The song of the brown thrasher is similar to those of the
mockingbird and catbird. Although the songs of the three eastern
species are much alike in form, there are great differences in the
seasons of song. The brown thrasher has the shortest period of
all. The song ceases, according to my records, on an average date
of July 11. The earliest date is July 6, 1921, and the latest July
18, 1940. When nesting begins individuals stop stinging, so that
the song is never so abundant late in May and in June as it is
late in April and early in May. Birds usually sing until the eggs
are laid and then cease until the young are out of the nest.
Sometimes the second-brood nesting follows the first so quickly
that there is no singing between broods.
"The limits of pitch in the songs in my records are B'' to
C'''', one octave and three tones, and curiously just a half tone
lower, in both lowest and highest limits, than my catbird records.
"Alarm notes about the nest consist of a loud call much
like the sound of a kiss, a whistled call like teeola, and
a series of harsh, slurred calls, like teea teea, repeated
six to ten times, gradually becoming higher in pitch and
louder." The kiss note is a loud smack, or sucking kiss,
something like the sound made by the clicking of a heavy pair of
pruning shears, a most startling sound for a bird to make and
perhaps effective in frightening away small enemies. The thrasher
also makes a local hissing sound about its nest.
Amelia R. Laskey writes to me from Tennessee: "There are
lovely 'whisper' songs given in both spring and autumn. The late
songs of the season are given in August and September. For
September 10, 1935, I have the following note: A brown thrasher
sang almost an hour in very soft tone. It consisted mostly of low
warblings but often contained phrases similar to spring songs, all
very clear, but inaudible a few feet away from the singer.
September 14: The 'whisper' songs continue. The bird was perched
today in shrubs about 3 or 4 feet from the ground. It sang with
closed beak. The song had overtones with undertones of soft
warbling, giving the impression at times of a duet."
The soft courtship songs, given while the birds are hunting
nesting sites, have been referred to under "Courtship."
Mrs. Laskey has observed this twice when she could see both birds.
There are very few birds whose songs can be well expressed, or
accurately recalled to mind, by the use of human words or phrases,
but it seems to me that the brown thrasher is one of them. The
oft-quoted words, "drop it, drop it--cover it up, cover it
up--pull it up, pull it up, pull it up," first written, I
believe by Thoreau in his "Walden," as fancied advice to
a farmer planting his corn, recall to my mind most vividly the
theme and the tempo of the thrasher's song, and I fancy that I can
see him perched on top of a tall birch tree beside the plowed lot.
Many other wordings have been attributed to this most versatile
bird, but there is not room to quote them all here. One of the
most elaborate versions is given by Mrs. H. P. Cook (1929) as one
end of a telephone conversation, like this: "Hello, hello,
yes, yes, yes, Who is this? Who is this? Well, well, well, I
should say, I should say, How's that? How's That? I don't know, I
don't know, What did you say? What did you say? Certainly,
Certainly, Well, well, well, Not that I know of, Not that I know
of, Tomorrow? Tomorrow? I guess so, I guess so, All right, All
right, Goodbye, Goodbye." F. Schuyler Mathews (1921) suggests
the following advice to the farmer: "Shuck it, shuck it; sow
it, sow it; Plough it, plough it; hoe it, hoe it." All these
interpretations seem to suggest the song that Forbush (1929)
describes as "a succession of phrases of two to four
syllables, loud, clear, rich, musical and of great variety, each
one delivered as a positive statement complete in itself, and
unrelated to the rest, with a brief pause after it." Mrs.
Nice (1931) made the following careful observation: "On April
1, 1926 I noted the number of times a Thrasher repeated each
phrase and found the scheme less regular than I had suspected; it
went thus: 2, 1, 2, 3, 2, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 2, 3, 3,
1, 2, 2, 2, 3, 1, 3, 4, 2, 3, 1, 3, 4, 2, 3, 2, 2, 2, 2, 2,
1."
Tilford Moore, of St. Paul, Minn., tells me that, on April 30,
1941, he saw a thrasher singing as it flew between two perches; it
did this twice.
Field marks.--A brown thrasher
could hardly be mistaken for any other bird within its range. It
is a long, slim bird with a long tail, bright reddish brown above,
with two whitish wing bars on each wing, whitish beneath, streaked
with blackish, a long bill and glaring yellow eyes.
Enemies.--Nesting as it does on or
near the ground, the eggs and young of the thrasher are
particularly vulnerable to the attacks of prowling predators, such
as dogs, cats, foxes, raccoons, skunks, weasels, probably
squirrels, and snakes. Crows, blue jays, and perhaps grackles may
rob the nests, if they can find them. Hawks, especially the
accipiters, may kill a few adults, though the thrashers are quite
expert in dashing into thick bushes and hiding. I have several
records of cowbirds' eggs in thrasher nests, but Dr. Friedmann
(1929) calls the thrasher "a decidedly uncommon victim of the
Cowbird. The species is the largest passerine bird affected by the
parasite, and is the largest bird definitely known to have hatched
and reared a young Cowbird. J. A. Allen saw a female Brown
Thrasher feeding a nearly full grown Cowbird in Western Iowa in
1868. . . . As far as I know, the late Dr. Allen's observation has
remained unique to this day." Tilford Moore saw a thrasher
feeding three young cowbirds.
Audubon's spirited plate shows a thrasher's nest being attacked
by a blacksnake, with several thrashers rallying to the rescue. He
(1841b) reports that the snake was finally killed and one injured
bird rescued. I once saw a pair of thrashers making a great fuss
around a bunch of oak scrub, where I soon discovered the cause of
their anxiety; a large blacksnake was coiled about their nest and
had evidently swallowed the eggs or young, as the nest was empty.
I tried to kill the snake, but the underbrush was too thick and it
escaped.
Thrashers are not immune from parasites, even while still in
the egg. Bagg and Eliot (1937) publish the following note from
Lewis O. Shelley:
The Thrasher is an uncommon summer resident here
[Westmoreland, N.H.], and it is a curious fact that, of all the
nests I have seen, each one harbored one or more "wormy"
eggs. Outwardly seeming in perfect shape and condition, an egg
turned over might reveal a neat round hole, one mm. in diameter,
bored in the under side, or more than one such hole. I found that,
if blown, the egg-shell crumbled after a short time, due to the
lining being eaten together with the yolk and albumen. By
dissecting two eggs from a nest of half-fledged young, I found the
grubs to be small white oval shapeless forms capable of great
elongation when feeding and very closely resembling, while
smaller, the Tachinids that so commonly sting larvae of
various Saturniidae caterpillars; but the mature insect is
more closely akin, in form, to the Hymenoptera or
membranous-winged flies, with well-developed maxilliae, probably
the organ wherewith the parasite drills an exit through the
egg-shell when the time arrives. It is notable that this parasite
differs from the Tachinids in that it emerges at perfection
and not as a grub.
Harold S. Peters (1936) lists three species of lice, five of
mites, two of ticks, and one fly, as external parasites on the
brown thrasher.
Winter.--The brown thrasher is a
permanent resident throughout the southern portion of its range,
but more or less migratory throughout the greater part of it. Most
of the thrashers leave New England during fall, mainly in October,
but there are a number of wintering records as far north as
Massachusetts. Henry Nehrling (1893) gives a very good account of
its migration and winter haunts:
Unobserved, silent usually from thicket to thicket, and in
bushes along streams and rivers, the Brown Thrush migrates
southward, ordinarily during October. The Southern States,
especially those bordering on the Gulf of Mexico, are the Brown
Thrasher's winter quarters. I have found the bird in southeastern
Texas from December to March. They usually remain near the water
where thicket succeeds thicket. They are especially common where
the magnolia, cherry-laurel, holly, dense blackberry and Mexican
mulberry bushes, Cherokee roses, and vines of many species, grow.
The ground swarms with insects of many kinds, the old leaves cover
larvae and snails, and the bushes are rich in berries. In these
thickets the Brown Thrush leads a very secluded existence, in
company with the Hermit Thrush, Towhee Buntings, White-crowned and
White-throated Sparrows, and others. It is here so shy and knows
so well how to screen itself from view that it is but rarely seen.
Here, its call-notes are seldom heard. In the dense hammock woods
of Florida, it is one of the most abundant winter birds. These
woods usually consist of large deciduous and evergreen trees, with
an undergrowth of low saw-palmettos, sparkleberry bushes, hollies,
similax, Carolina jasmine, and a host of other tropical species.
Brown Thrasher*
Toxostoma rufum
*Original Source: Bent,
Arthur Cleveland. 1948. Smithsonian Institution United States
National Museum Bulletin 195: 351-374. United States Government
Printing Office
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