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Red-tailed
Hawk
Buteo jamaicensis [Eastern
Red-tailed Hawk]
[Published
in 1937: Smithsonian Institution United States National Museum
Bulletin 167: 147-165]
The red-tailed hawk, with its various races, is the most widely
distributed, most universally common, and best known of all our
hawks, though in certain sections some other species may be much
commoner. For example, in my home territory the red-shouldered
hawk outnumbers it nearly ten to one; and on the prairies and
plains of the Middle West Swainson's and ferruginous roughlegs
are, or were, commoner than redtails. But this fine hawk, the
largest and most powerful of our eastern Buteos, is no longer
common over much of its former range. The widespread prejudice
against all hawks is exterminating this useful species much faster
than some of the most destructive hawks that are better able to
take care of themselves, craftier, and swifter awing. It will be a
sad day indeed when we shall no longer see the great redtail
sailing over the treetops on its broad expanse of wing and ruddy
tail, or soaring upward in majestic circles until lost to sight in
the ethereal blue, or a mere speck against the clouds.
The distribution of this and the red-shouldered hawk in
southeastern Massachusetts has always interested me. During my 50
years of experience with them, I have learned to regard them as
competitive species, each intolerant of the other, antagonistic
and occupying entirely separate ranges. In the western half of
Bristol County, where the prevailing forest growth consists of
hardwood trees, chestnut (formerly), oaks, and maples, with only
scattering growths of white pine (Pinus strobus), the
red-tailed hawk was until recently practically unknown; this
region has always been the center of abundance of the
red-shouldered hawk. On the other hand, in the Cape Cod region,
comprising the southeastern part of Plymouth County and all of
Barnstable County, where the prevailing forest growth is pitch
pine (Pinus rigida) and stunted oaks, the redtail is the
common species and the redshoulder so rare that I have seen only
one there in all my experience. In the intervening territory,
where the prevailing forest growth is white pine, both species
occur, but only in widely separated localities. In this latter
region, during recent years, persecution under the bounty system
has nearly exterminated all hawks. Meantime redtails began to
invade the hardwood region in western Bristol County, supplanting
the redshoulders in some of their long-established haunts. In
1929, 1930, and 1931, red-tailed hawks moved into three different
tracts of hardwood timber that had been occupied by red-shouldered
hawks for upward of 40 years, driving out the former tenants and
in two cases appropriating their old nests. The larger and
stronger bird seems to be the dominating species.
William Brewster (1925) noted the reverse of this replacement,
for he writes: "That the Red-shouldered Hawk should have
remained almost unknown in the Umbagog Region until after the
Red-tailed Hawk had practically ceased to reappear, and that not
long thereafter it should have apparently established itself as a
summer resident in at least two localities, are matters of
considerable interest, in view of the fact that throughout much,
if not most, of Massachusetts there has been essentially similar
and contemporaneous replacement of the greater by the lesser
bird."
Spring.--Throughout the
northernmost part of its range the red-tailed hawk is mainly
migratory, a large majority of the birds wintering somewhat
farther south. But a few individuals remain during winter,
especially during mild seasons, not far from the northern limits
of their summer range. I have seen them in Massachusetts during
every winter month. Those that remain during winter or those that
return early in the season begin their nest building late in
February or early in March; I have seen a wholly new nest half
completed and decorated with green pine twigs and down as early as
February 18, over a month before the eggs are laid.
Courtship.--I believe
that this and other large hawks remain mated for life, but, if one
of the pair is killed, the survivor soon secures a new mate. The
birds are apparently in pairs when they arrive on their breeding
grounds, but they indulge in nuptial demonstrations more or less
all through the nesting season. I have seen a pair of these hawks,
in May when there were young in the nest, indulging in their joint
flight maneuvers high above the woods where the nest was located;
they soared in great circles, crossing and recrossing each other's
paths, sometimes almost touching, and mounting higher and higher
until almost out of sight; finally one partially closed its wings
and made a thrilling dive from a dizzy height, checking its speed
just before it reached the woods. E. L. Sumner, Jr., refers in his
notes to such a flight: "About ten times, while they were
circling near together, the male would lower his legs and adjust
his circles so that he came above his mate, and about four times
he actually touched her back, or so it seemed." M. P. Skinner
says in his notes: "These hawks at times performed wonderful
evolutions high in the air, either one bird alone or several at a
time. Such hawks would mount up to a high altitude, then half
close the wings and drop down on an invisible incline at great
speed only to open the wings again and shoot up at an equal angle.
This was repeated again and again while the hawk described a
series of deep V's and gradually passed out of sight in the
distance."
Mr. Sumner saw a male western redtail approach a female that
was perched in a tree, hang for a moment just over her, then
alight on her back and stay there about 40 seconds, with quite a
bit of wing motion to balance himself; he then got off and perched
beside her on the branch, but he soon flapped off and began to
circle.
Clarence F. Stone writes to me about the mating antics of a
pair of red-tailed hawks on a lofty horizontal limb of an elm tree
near their nest:
Stopping to survey the woods before I entered, I beheld a
pair of Red-tailed Hawks cavorting step by step, towards each
other. Since they had not discovered my presence the performance
continued to a finish. Stepping sideways until they were wing to
wing and facing each other almost breast to breast, both birds
suddenly dropped down backwards until there was physical contact
below the limb, and thus the act of copulation took place.
Immediately after, both hawks took to the air around and around
each other in wide circles.
Another recorded note concerning the Red-tailed Hawk tells
of a pair proceeding to reline their many years old nest, but
before time for the eggs one of the birds was killed by a farmer.
All the remainder of that season, the bereaved hawk hunted and
lived in the nest woods. On the following Spring this Red-tail
returned alone and even did quite a bit of relining of nest--so
much that I climbed up to see if there were eggs. As this nest was
near home I visited it frequently during the season up to June,
but always the Red-tail remained unmated. I think this instance
shows "faithfulness" more than lack of opportunity to
mate again.
Nesting.--My personal
experience with the nesting habits of the red-tailed hawk in
southeastern Massachusetts has been limited to the study of 19
nests over a period of 40 years, from which it appears that it is
not a common bird here. Twice we found two nests in one season and
one year we found three. The local distribution has been referred
to above. Contrary to the experience of others elsewhere, we have
found the redtail much less constant in its attachment to its
nesting haunts than the redshoulder. In three cases we found them
in the same patch of woods, but in different nests, for two years
in succession, and once for three years. A popular nest at Blue
Ridge, 35 feet up in a red oak in mixed woods, on a ridge between
an open bog and a maple swamp, was occupied by a red-shouldered
hawk in 1920; in 1928 it was occupied by a pair of broad-winged
hawks; the following year a pair of redtails took possession of it
and raised a brood of young; in 1930 it remained unused; in 1931
the redtails were back in it again and raised another brood; but
in 1932 it was deserted again; raising a brood successfully did
not encourage the hawks to return.
Our longest record covers a period of 13 years, during which
time the nest was actually found in only four years. The territory
covers a very extensive area in Mansfield and Norton in which
there are a number of large patches of heavy timber of various
kinds, white pines, oaks, and maples, interspersed with open bogs,
swampy woods, cleared lands, and pasture. The redtail's nest was
first discovered by my companions, F. H. Carpenter and C. S. Day,
in 1920; it was an ideal situation, 54 feet from the ground on
horizontal branches, against the trunk of a giant white pine that
stood on the edge of a grove of heavy pines, overlooking an open
meadow. We did not find the nest again until 1924, when we
discovered it fully a quarter of a mile away; it was 52 feet up in
one of a small group of scattered white pines in an open
situation. Two years later the hawks were back in the old original
nest in the big pine. The nest remained vacant until 1932, when it
was again occupied. I have no doubt that the hawks nested
somewhere in that big tract during all the intervening years, for
we often saw them, but were unable to locate the nest in a region
so difficult to hunt thoroughly. Mr. Day, who has all the eggs
collected from this locality, is convinced that three different
females presided over this territory, as shown by the three
distinct types of eggs laid.
As mentioned above, red-tailed hawks invaded, in three
successive years, three separate localities that had been occupied
previously by red-shouldered hawks. I suspect that these three
invasions were all made by the same pair of redtails, as the
second and third localities are less than a mile and a half from
the first. The "reservoir woods" in Rehoboth was once a
fine, large tract of heavy chestnut, oak, and maple timber,
partially swampy and drained by a small stream. A pair of red-
shouldered hawks had nested continuously in these woods from 1882
to 1923, when the last nest we found there was built in a large
scarlet oak 48 feet from the ground. In 1924 this nest was
occupied by a pair of barred owls and in 1928 by a pair of red-
tailed hawks; I did not visit the locality during the intervening
years. The following year, 1929, we found the redtails nesting in
the Blue Ridge nest referred to above. In 1930, they, or another
pair, invaded another big tract of hardwood timber, Goff's woods,
less than a mile away, where red-shouldered hawks had nested for
nearly 50 years, and built a new nest 45 feet up in a red oak. And
the next year they were back again in the Blue Ridge nest. Since
then we have been unable to find any hawk's nests in any of the
three localities, though much of the old woods is still standing.
All the nests found in the hardwood region were oaks, varying
in elevation from 35 to 48 feet. Those in the white-pine region
were all in white pines and 35 to 70 feet above the ground. On
Martha's Vineyard we found the lowest nests in the oak groves on
the western part of the island; one huge nest was only 15 feet
from the ground and another 30 feet. In the Cape Cod region the
redtails nest in the lightest pitch pines they can find, from 18
to 35 feet up, and occasionally in white pines where these trees
can be found.
The nests of the red-tailed hawks will average somewhat larger
than those of the red-shouldered; typical nests are from 28 to 30
inches in outside diameter, the inner cavity being 14 or 15 inches
wide and 4 or 5 inches deep. The largest nest I ever measured was
42 inches in longest by 19 inches in shortest diameter. The nests
are usually quite flat and shallow; but one that had been added to
for an unknown number of years measured 3 feet in height. Dr. H.
C. Oberholser (1896) gives the measurements of 7 Ohio nests that
are somewhat larger than my averages; his largest nest measured 36
inches in height and 48 by 30 inches in outside diameter; the
inner cavity was 7 inches deep.
The nests are well made of sticks and twigs, half an inch or
less in thickness, and neatly lined with strips of inner bark, of
cedar, grapevine or chestnut, usnea, and usually at least a few
green sprigs of pine, cedar, or hemlock. Some nests are profusely
and beautifully lined with fresh green sprigs of white pine, which
are frequently renewed during incubation and during the earlier
stages in the growth of the young.
I have spent considerable time, with rather meager results,
attempting to watch the nest-building activities of these hawks.
They "stake out their claim" late in February or early
March, a month before the eggs are deposited, by marking the nest
they propose to use with a sprig of green pine. Nest building is a
very deliberate process; the birds visit the nest at very
infrequent intervals and are very cautious about it. If they
suspect that the nest is watched they will not come near it. In
order to watch them successfully it is necessary to have a blind
that offers perfect concealment; a brush blind is utterly useless,
as the hawks can see the slightest movement in it, and will not
come near the nest again until the intruder departs. I believe
that both sexes assist in nest building, though I have not proved
it. Old nests are sometimes repaired in the autumn.
The nesting habits of the red-tailed hawk in other parts of its
range differ somewhat from the above. Major Bendire (1892) quotes
Dr. William L. Ralph as to its nesting in Oneida and Herkimer
Counties, New York, as follows:
In this vicinity the Red-tailed Hawk prefers birch trees
above all others to build in, and about 80 percent of their nests
will be found in such situations. The remaining 20 percent is
about equally divided among beech, maple, hemlock, elm, and
basswood trees. Why these birds should prefer birch trees I do not
know, for they are usually not very hard to climb, while the most
difficult of their nests to reach were built in elm, hemlock, and
basswood trees. They generally select the largest and tallest
trees they can find to build in, and their nests are situated near
the tops, in crotches formed by two or more large limbs, or at the
junction of large limbs with the trunks. They are usually placed
from 60 to 70 feet from the ground.
William A. and George M. Smith, of Lyndonville, N.Y., have sent
me data on 46 New York sets, showing very different preferences;
23 of their nests were in beeches, 9 in maples, 5 in oaks, 4 in
elms, 3 in basswoods, and 1 each in ash and hemlock. The heights
from the ground varied from 34 1/2 to 78 feet, measured; and 24
were 60 feet or over. There were 16 sets of three, but no larger
sets. S. F. Rathbun tells me that he has taken a set of four in
central New York, and about half of Dr. Ralph's sets were fours.
The largest nest I have heard of was found by Verdi Burtch
(1911) near Branchport, N.Y.; it was placed in a big pine tree and
measured 3 by 4 feet in diameter. He says: "My first set from
these woods was taken March 31, 1890 (20 years ago) and there has
been a nest in there or the adjacent woods nearly every year since
that time." A. D. DuBois mentions, in his notes, a nest found
near Ithaca, N.Y., that was 80 or 90 feet from the ground in a big
pine tree. He also sent me notes on three nests found in Sangamon
County, Ill. One was 50 feet from the ground "in the
uppermost main crotch of an elm tree"; another was at the
same height in a white oak; and the third was in the top of a big
sycamore.
Throughout the greater part of its range the red-tailed hawk
seems to be more constant in its attachment to its nesting site
than we have found it in New England; it often returns year after
year to the same patch of woods. As it usually selects the tallest
tree it can find the nest is often a great height, even over 90
feet from the ground. It does not seem to be at all particular as
to the choice of a tree, except as to size; various pines, oaks,
maples, hickories, elms, sycamores, and poplars have been used.
Small patches of heavy tall timber are preferred, and the nest is
usually on or near the edge so that the bird can have a good
outlook, and nests are often built in more or less isolated trees
in open situations. I believe that the birds prefer to build a new
nest each year, but they sometimes use the same nest for
consecutive years, though oftener they return to it after an
interval of a year or two. Lewis O. Shelley writes to me that he
has know a pair to use the same nest each season for four or five
years. Often they appropriate a nest previously used by another
hawk, owl, or crow or build on an old squirrel's nest. A. W.
Brockway tells me that one of his nests was built on top of a gray
squirrel's nest in which he could hear the young squirrels chatter
as he pressed against the nest. For three seasons in succession J.
A. Singley (1886) found a nest occupied by great horned owls early
in the season and later by red-tailed hawks; this was in Texas
where the owls nest early in the winter. If their first set of
eggs is taken, the hawks will lay a second set, three or four
weeks later, but usually in another nest; very rarely a third set
may be laid; and Bendire (1892) says "on very rare occasions
even a fourth."
Eggs.--In the eastern and
southern portion of its range the red-tailed hawk lays almost
invariably two eggs; I have never found three and twice have found
incubated sets of one. In central and western sections sets of
three are commoner, sets of four are not rare, and as many as five
eggs have been found in a nest. The eggs are ovate,
elliptical-ovate, or oval in shape, and the shell is finely
granulated or smooth without gloss. The ground color is usually
dull or dirty white, sometimes faintly bluish white, or more
rarely pale greenish white. The eggs average much less heavily
marked than red-shouldered hawks' eggs. They are often nearly or
quite immaculate, but they are usually more or less sparingly
spotted; some are handsomely marked in even or irregular patterns,
but very rarely heavily blotched. The markings are in various
shades of dull reddish or yellowish browns, "snuff
brown" to "ochraceous-tawny," more rarely
"warm sepia," "auburn," or "russet";
some show underlying spots of "pale Quaker drab," or
"pallid purple drab." A series of eggs from one female
usually runs true to type, as to shape, color, and markings; and
when a new female replaces her, a different type of eggs often
results. The measurements of 59 eggs average 59 by 47 millimeters;
the eggs showing the four extremes measure 66 by 50, 64.5
by 51, 55 by 45.5, and 59.5 by 44
millimeters.
Young.--Incubation lasts for
about 28 days; the male assists the female somewhat in this,
brings food to her while she is incubating, and helps to feed the
young. I have seen the male bring food to the nest, and his mate
feed it to the young. The incubating bird is watchful and very
shy; it is almost impossible to approach within 100 yards of the
nest without flushing her, if she is watching. One of my nests was
fully that distance from a rocky ledge, from behind which I often
attempted to watch the nest; almost invariably, as soon as I
showed my head above the crest of the ledge, if I could see her
head on the nest, she would immediately stand up in the nest and
fly away; and she would not return until after I left the woods.
On other occasions, when she was invisible on the nest, I could
walk to within 10 yards of the tree before she would fly; I
believe that at such times she was asleep on the nest. Even after
the young have hatched these hawks are very cautious about
returning to the nest; repeatedly I have waited in vain for their
return, even when well concealed, after they had once seen me; and
their eyes are exceedingly keen. They seem to be much more
concerned about their own safety than about the welfare of their
eggs or young.
The young hatch at intervals of one or two days and remain in
the nest for four weeks or more. Often one of the eggs proves to
be infertile, and oftener one of the young dies and is thrown out
of the nest, or is forced out of the nest and is killed by the
fall. Norman Criddle (1917) writes:
The number of eggs laid by each female varies somewhat and
seems to depend, at least to some extent, upon the food supply. In
1917, the six nests under observation close to the writer's home
contained but two eggs each and in only one of the six did the
parents succeed in rearing more than one young though both were
hatched in every instance. The first nest was discovered on May 6,
containing two eggs. Other nests with eggs were located as late as
June 14. It is difficult to account for the mortality among the
young, though it is noteworthy that the deaths occurred while they
were still quite small, and that the latest hatched, and
consequently smallest, was invariably the one to die. Dead
examples presented no indication of violence but seemed to show
that, in all probability, death was due to starvation, the lack of
food being due in its turn to a scarcity of ground squirrels
(gophers) and to the unusual number of hawks nesting in the
district.
The curious habit of the old birds in gathering a green
leafy bough and placing it in the nest, characteristic of
Swainson's hawk also, is very marked in the Red-tail, a fresh
bough being gathered at least once daily during the time when the
young are small. There has been some doubt hitherto as to the
cause of this habit, but by observing the nestlings I am led to
believe that the bough acts as a sun shade, as the young have been
seen to repeatedly pull the bough over themselves and crouch
beneath it. Doubtless it also acts as a shield and hides the young
from their enemies. The leaves are also occasionally eaten.
As the young develop they acquire a good deal of boldness
and defend themselves with both beak and claws. They have a habit
of closely watching the intruder backing up meanwhile at the
approach of a hand; then suddenly they leap forward with wings
outstretched, and it requires a rapid movement to escape their
onslaught. The old birds make no efforts to defend their young,
but fly high overhead uttering loud cries which are, at times,
answered in a shriller key by the young beneath.
The young, when half grown, become very lively, walking about
in the nest, stretching or flapping their wings, backing up to the
edge of the nest to void their excrement in a long stream far over
the edge; the ground under a nest of young hawks is well decorated
with a circle of white. Their eyes are very keen, and they
frequently raise their heads to watch passing birds or to look for
the return of their parents. Their weak, peeping notes are heard
occasionally, but when one of their parents is sighted they become
quite excited and indulge in louder screams in feeble imitation of
the adult's notes. I have never happened to see the young leave
the nest, but Mr. Sumner's notes, applying to the western race,
describe such an event. Mr. Shelley writes:
The adults are quiet during the incubation period until the
young are on the wing. As soon as this stage is reached, they are
brought east of the hill where the nest is situated to the broad,
open fields and mowings of the nearby farms, where they spend the
forenoons hunting their legitimate prey and nothing else.
Afternoons as a rule they skirt the country to the west of the
nesting hill. But on the east side their calls can be heard all
forenoon for a month or more, during the period the young are
being taught to fare for themselves. Many a time I have seen them
catching mice. An adult plunges down 50 to 10 feet or so at a
scuttling mouse, checks its rush a few feet above the ground, and,
turning onto its back, gives a wheezy whistle of two syllables,
whereupon one of the circling young dives, holds itself suspended
clumsily over the spot marked by the parent, and, quite often,
obtains the rodent when it moves again. The parents do, rarely,
drop disabled mice from a good height as though discarding them,
but in reality it is done so that the young may catch them in
midair, which they attempt to do with fair luck; I have seen it
done on several occasions.
Mrs. A. B. Morgan (1915) gives an account of a young red-tailed
hawk which she raised in captivity that developed into a very
interesting and most intelligent pet.
Plumages.--The small downy
young red-tailed hawk is well covered above with long, soft, silky
down, buffy white or grayish white in color; the white hairlike
filaments on the head are erected in life and fully half an inch
long; the down on the under parts is shorter and scantier. This
first down is replaced later by a whiter and woollier down. When
about 17 days old the wing quills appear, closely followed by
those of the tail. Before the young bird is half grown the
feathers appear on the scapulars and the mid-dorsal tracts; the
feathers come in next on the pectoral tracts. By the time the bird
is four weeks old it is nearly fully grown and almost fully
fledged, the last of the down persisting on the head, central
belly, and legs. It is now ready to leave the nest and is able to
fly.
In fresh juvenal plumage, in June and July, the upper parts are
"warm sepia" to "bone brown," with narrow
edgings of "tawny" or "ochraceous-tawny"; the
tail is "bister," barred with brownish black, tinged an
tipped with buffy white, and silvery white on the under side, with
the bars showing through; in western birds the tail is often
tinged with "tawny" or "orange-cinnamon,"
sometimes extensively so, but in eastern birds this color is
seldom, if ever, seen; the under parts are largely white, more or
less tinged with "ochraceous-buff," which fades out to
white later in the season; the throat and sides of the neck are
narrowly streaked with sepia, and the belly and flanks are heavily
streaked or spotted with a dark sepia, suggesting the adult
pattern. This plumage is worn throughout the first winter with
little change except by wear and fading, the buffs being replaced
by dull white.
A complete molt from the juvenal into the adult plumage begins
very early in summer or into the fall, with much individual
variation. I have seen a young bird with new red feathers in its
tail in February, and birds with missing flight feathers are often
seen during the nesting season. At the completion of this molt in
fall young birds are practically indistinguishable from adults.
Young birds raised in captivity have molted from the juvenal into
the red-tailed adult plumage when a little over a year old. I have
examined a large series of eastern birds and have not been able to
recognize a second-year plumage, such as seems to occur in harlani;
immature specimens of calurus often have reddish tales with
numerous narrow black bars; these are probably first-year birds
with erythristic tendencies. Neither erythrism nor melanism seems
to occur in eastern birds, but cases of nearly, or quite, perfect
albinism have been reported. Adults have one complete annual molt,
which may begin in spring or early in summer and may be completed
in September or October.
Food.--It is generally
conceded that the red-tailed hawk is a highly beneficial species,
as its food consists mainly of injurious rodents and as it does
very little damage to domestic poultry or wild birds. Dr. A. K.
Fisher (1893) writes:
Of 562 stomachs examined by the author, 54 contained poultry
or game birds; 52, other birds; 278, mice; 131, other mammals; 37,
batrachians and reptiles; 47, insects; 8, crawfish; 13, offal; and
89 were empty. It has been demonstrated by careful stomach
examination that poultry and game birds do not constitute more
than 10 percent of the food of this Hawk, and that all the other
beneficial animals preyed upon, including snakes, will not
increase this proportion to 15 percent. Thus the balance in favor
the Hawk is at least 85 percent, made up largely of various
species of injurious rodents--a fact that every thoughtful farmer
should remember. . . .
The increase of any animal is always followed by a relative
increase of its natural enemies. This is clearly shown on the
river front in the vicinity of Washington, D.C., where the recent
improvements have redeemed several hundred acres of ground from
the tidal flats; and already in many places rank vegetation has
grown up, affording shelter and sustenance for hordes of mice. At
present in winter and early spring it is not uncommon to see ten
or fifteen Red-tailed Hawks in different parts of this flat
attracted hither by the abundance of their natural food. Prior to
the reclamation of the flats not more than a pair or two were to
be seen in the same neighborhood during the winter.
Of 173 stomachs of this hawk examined by Dr. B. H. Warren
(1890) in Pennsylvania, 131 contained the remains of mice, 6 of
rabbits, 3 red squirrels, 2 skunks, 18 small birds, 14 poultry, 3
insects, 3 snakes, and 4 offal or carrion. He says: "I have
repeatedly found three or four mice in the viscera of one bird,
oftentimes five, and in a few instances as many as seven of these
destructive little rodents were obtained from the crop and stomach
of one hawk."
Dr. George M. Sutton (1928) reports on the stomach contents of
32 redtails, taken in Pennsylvania in October, as follows:
Twelve stomachs were empty; in the twenty stomachs which
held food were eleven Field Mice, four Short-tailed Shrews, three
Red-backed Mice, three Chipmunks, three small Garter Snakes, two
Red Squirrels, one Winter Wren, one Song Sparrow, one Hermit
Thrush, one Gray Squirrel, one Brown Rat, one half-grown White
Leghorn Chicken, one large grasshopper, two crickets, and one
large beetle of the family Elateridae. Such an array of food items
in only twenty-two stomachs is noteworthy. Only seven of these
stomachs held but one item; the others had a variety in each. If
the above stomach contents are at all normal the red-tail captures
about five harmful or unimportant organisms to one economically
valuable one.
The following mammals have been detected in the food of this
hawk: house mice and various species of field and wood mice, rats,
various squirrels, both arboreal and ground species, raccoons,
gophers, prairie dog, spermophiles, woodchuck, rabbits, moles,
bats, shrews, chipmunks, muskrat, porcupine, weasels, and skunks;
as many as nine red squirrels have been found in a nest at one
time. The following interesting account of a redtail attacking a
cat is published by E. D. Nauman (1929):
A large Red-tailed Hawk came out of the timber and leisurely
flew around over the meadow, hovering over one point a moment for
special inspection. Then he flew back to the woods again. A few
minutes later he flew out and hovered over the same place, then
returned to the woods as before. After having performed this round
trip movement several times, the Hawk finally flew to this point
and plunged down into the meadow. Instantly there was a mighty
commotion. Hissing, flopping, spitting, caterwauling; and one
could see feet, claws, wings and tails whirling about just over
the grass. The air was full of fur and feathers for a few moments,
then the Hawk made his getaway, and with feathers much ruffled
flew for the timber as fast as his wings could carry him. And an
old gray tom cat went with great bounds in equal haste for the
farm buildings! Both Tommy and hawk were licked but still able to
go.
The bird list includes domestic poultry, young turkey, pintail,
teals, and other wild ducks, gallinules, rails, pheasants, ruffed
grouse, Hungarian partridge, various quails, doves, screech owl,
kingfisher, woodpeckers, crow, starling, grackles, meadowlark,
horned larks, orioles, various sparrows, juncos, thrushes, robin,
and bluebird. Verdi Burtch (1927) found a freshly killed
red-shouldered hawk and later saw a red-tailed hawk feeding on it.
Lucy V. Baxter (1906) surprised an adult red-tailed hawk feeding
on a freshly killed immature hawk of its own species. Probably
most of the small birds are killed during the nesting season as
food for the small young, though the young hawks are fed largely
on mice and squirrels. Ralph J. Donahue (1923) writes:
"Before the eggs of the red-tails hatched, the parents fed on
rodents--mostly the striped ground squirrels (Spermophile). After
the young got out of the shells, the whole bill of fare was young
chicken. At different times we found chickens to the number of
seven. There were times when we could not go to the nest for a
week or two, and it may be there was other food fed to the young
during that time."
Miscellaneous items of food include rattlesnakes, bull snakes
and smaller snakes, lizards, turtles, frogs, toads, salamanders,
crawfish, grasshoppers, crickets, beetles, grubs, caterpillars,
centipedes, spiders, earthworms, and maggots.
Two common hunting methods of the red-tailed hawk are the lofty
soaring flight, from which its keen eyes detect its prey far
below, and its slow flapping or sailing flight low over the fields
and meadows, much after the manner of the marsh hawk or roughleg;
a third, and perhaps the commonest, method is watchful waiting on
some commanding perch on tree or post from which it can quickly
pounce on any moving object that it sees. Much of its hunting must
be in the forests, for many woodland mice and squirrels are
included in its food. To capture such active animals as red or
gray squirrels, it is often necessary for these hawks to hunt in
pairs; these lively animals can easily avoid the swoops of a
single hawk by dodging around a tree; but, if there is a hawk on
each side, the squirrel is doomed unless it can scamper into a
hole. Col. N. S. Goss (1891) says that these hawks while
"sailing often fill their craws with grasshoppers, that
during the after part of the day also enjoy a sail in the
air." Mr. Shelley says in his notes that "it is also a
great experience to see these large Buteos alight in a newly hayed
field to catch grasshoppers and crickets; as they hop along the
wings are always maneuvered to give the bird a rising impetus and
timed so that the feet no more than touch the ground when the
insect is plucked and the bird is clear of the ground on the next
bound for the insect ahead. More than anything else, this maneuver
resembles the floppings of a hen with its head cut off, only more
mathematical, to give a crude description."
Behavior.--The ordinary
flight of the red-tailed hawk is rather slow and heavy, as it
travels along in a straight line, with rather slow wing strokes.
But its soaring flight high in the air is inspiring, as it mounts
gracefully, gathering altitude rapidly, with no apparent effort,
with its broad wings and tail widely spread and motionless except
for occasional adjustments to changing air currents. Once, as I
stood on the brink of a precipice looking down over a broad
valley, I saw below me a red-tailed hawk floating over the valley
and looking downward for game; it was facing a strong wind and was
perhaps buoyed up by rising air currents, as it was poised as
motionless as if suspended on a wire; it remained in one spot for
three or four minutes and then sailed over to another spot a few
rods away, where it hung for a similar period. Its spectacular
"nose dives," referred to above, are thrilling and well
illustrate its mastery of the air. Dr. B. H. Warren (1890)
describes some interesting maneuvers as follows:
Red-tailed Hawks in their fall migrations are gregarious.
One clear, cold autumn afternoon in 1876, I saw, near West
Chester, a flock of these hawks. The sky was destitute of clouds,
except a cumulus stratum directly beneath, and apparently about
half way between the hawks and the earth. In the center of this
vapor was an opening of sufficient size to enable me to watch the
gyrations of the birds; two of them suddenly separated from the
main body, approached each other screaming, and apparently with
great rage. They descended screaming, and, to all appearances,
clinched, to within about one hundred yards of the earth, when
they parted. Evidently neither bird had received much injury, as
they both, after taking short flights across the meadow, ascended
in company with two or three of their companions that had
accompanied them part way down, to the main body. Another
individual closed his wings until the body presented a triangular
outline, descended with almost lightning-like rapidity to the top
of a sycamore, where it alighted, and remained for some seconds
pluming itself. This party of hawks, after performing for nearly
twenty minutes, these, and numerous other aerial antics, continued
their southern flight.
Illustrating its marvelous powers of vision, he says: "A
clear morning in March, I saw a Red-tail circling over the
meadows; every circle took him higher and higher in the air, until
at an altitude where he appeared no larger than a blackbird, he
stopped, and with nearly closed wings, descended like an arrow to
a tree near by me; from this perch, almost the same instant he had
alighted, he flew to the ground and snatched from its grassy
covert a mouse. The momentum with which this bird passed through
the atmosphere produced a sound not very unlike that of the rush
of distant water."
This hawk is generally regarded as a sluggish, inactive bird,
for it spends much of its time standing erect on some lofty perch,
slowly scanning its surroundings. It is one of the shyest of our
hawks; a man on foot can seldom approach one to within 100 yards,
and often it will fly at twice that distance. But it seems to be
less afraid of a man on a horse or in a vehicle; in regions where
hawks are not much persecuted one can sometimes ride up within
gunshot range.
A wounded redtail is a formidable object, as it throws itself
on its back and presents its sharp and powerful talons; it will
grab a gun barrel or stick and allow itself to be lifted up; or it
will fasten its claws in the hand or arm of one who tries to
handle it and can only with great difficulty be made to let go.
Once, while I was hunting with John B. Semple in Florida, a
wounded redtail dropped a long way off among some patches of saw
palmetto; after a long search in vain we sent his springer spaniel
to hunt for it; the plan worked successfully, but the dog was
surprised and much frightened, as the infuriated hawk rushed out
and attacked him.
These hawks are not at all courageous in defense of their nest;
they generally keep at a safe distance or disappear entirely; only
on rare occasions has one been known to even attempt to attack a
climber; I have seen it only once. Only twice have I seen one
return to its nest when I was in plain sight near the nest tree;
once when I was almost under the tree the hawk settled on the nest
and would not leave until I rapped the tree.
Its behavior toward other birds is generally an attitude of
stolid indifference. I have seen it drive away other hawks from
the vicinity of its nest and, as stated above, have known it to
preempt old-time nesting haunts of red-shouldered hawks. I have
repeatedly seen it attacked by a party of crows; it often pays no
attention to them but sometimes turns on its back and displays its
talons, at which the crows beat a hasty retreat; occasionally the
crows pay the extreme penalty for their temerity; crows have often
figured in the food of this hawk. Kingbirds and blackbirds often
attack the redtail and drive it away from their nesting sites, but
I doubt if the hawk ever retaliates. Mr. Skinner says in his
notes: "Once I found one near Southern Pines being tormented
by four robins. It protected itself fairly well while in the top
of a tall pine, but when it flew 26 more robins, which had been
concealed in the foliage, gave chase and joined their efforts to
the pecks of the first four tormentors."
Mr. Sumner once saw a redtail attack and drive away a horned
owl that had ventured too near its nest. Great horned owls
habitually occupy old nests of the eastern redtail, probably
preempting them before the hawks are ready to use them. I have
always regarded these two as supplementary species, one hunting by
day and one by night in similar regions and preying on similar
victims. I once surprised one of these owls feeding on the remains
of a freshly killed red-tailed hawk.
Voice.--The red-tailed hawk
occasionally utters a note similar to that of the red-shouldered
hawk, but usually it is quite distinct. The characteristic cry is
described in my notes as a long drawn out, harsh, rasping squeal, kree-e-e-e-e-e,
suggesting the squeal of a pig. It has also been written cree-e-e,
cree-e- ep, or pee-eh-h. Bendire (1892) gives it as kee-aah,
the redshoulder note, so often imitated by the blue jay; he also
gives another note, chirr or pii-chiir, "when
perched on some dead limb near their nest." The note has been
said to resemble the sound made by escaping steam, but I could
never quite see the resemblance.
Field marks.--Its outline,
broad, somewhat rounded wings, and broad, rather short tail mark
it as a Buteo. In adult plumage it should be easily
recognized. As it flies straight away in the woods, or as it
wheels in soaring flight, it shows a glimpse of its red tail, with
no barring on the under side of it, in marked contrast with the
conspicuously black and white barred tail of the redshoulder. The
under side of the wing is whitish, without bars, but with a dark
border formed by the dusky tips of the primaries and secondaries
and there is usually a dark wrist mark near the bend of the wing.
The sides of the head are very dark and the breast is largely
whitish, with dark streaks only on the belly and flanks. The young
bird looks much like a young redshoulder; it has a faintly barred
tail, and the streaking on the under parts is more like that of
the adult redtail, very scanty on the breast, than like the young
redshoulder, which is more uniformly streaked below.
Fall.--Early in September,
red-tailed hawks begin to drift southward from New England and
other northern parts of their range. These fall flights are very
spectacular and usually contain a variety of species; they are
seen to best advantage on clear cool days with a northwest wind.
These large mixed flights often contain hundreds of individuals,
spread out over a wide area and continuing to pass for several
hours. Dr. Fisher (1893) has seen a flock containing 65 red-tailed
hawks "flying in a comparatively compact body, probably not
more than a few feet from each other." H. S. and H. B. Forbes
(1927) thus describe a flight as witnessed in New Hampshire on
September 14, 1926:
Far out to the northwest two Hawks, perhaps a mile away,
were seen wheeling over the valley at a slightly lower level than
our point of observation. Then, as if from nowhere, other Hawks
rapidly appeared, swooping, turning, and soaring upwards in
irregular steep spirals. More and more individuals appeared until
the specks resembled a swarm of large insects, black against the
pearl gray clouds. The total number was estimated to be between
thirty and forty. Now they soared slowly, now flew with rapid wing
beat at great speed. Each individual chose his own course without
evidence of leadership. In from five to ten minutes (the exact
time unfortunately was not noted) the flight had gained great
altitude and to our astonishment the highest birds began to
disappear in the clouds, some of them reappearing and again diving
into the mist. Finally the whole flight had spiralled upward into
the cloud mass and was lost to view. Once, half a minute later, a
few specks wheeled out toward us and for a moment could be dimly
seen through the edge of the cloud. That was the last glimpse.
Dr. Thomas S. Roberts (1932) writes from Minnesota:
While driving from Ten Mile Lake, Otter Tail County, to
Breckenridge on the Red River, on October 7, 1927, the writer,
accompanied by Mr. Kilgore and Mr. Breckenridge, passed through
what was evidently a large migration of the Redtails. There were a
few scattered all over the country, but on the open prairie
between Nashua and Campbell, in Wilkin County, many of the fence
posts, telephone and telegraph poles, and straw-stacks and
hay-stacks, were occupied by birds, while others circled in the
air, and a few were walking about on the ground. Forty-eight were
counted, most of them in a limited area.
Maurice Broun (1935) says of the fall migration at Kittatinny
Ridge, Pa., in 1934:
It may come as something of a surprise to learn that these
splendid birds made up fully 50% of the entire Hawk migration. The
first Red-tails recorded were two on September 30. No conspicuous
movement took place until October 12, when 205 birds were counted.
Thereafter during the month there were nine days of relatively
heavy flights, the greatest number of 427 birds occurring on
October 23. The first part of November, however, brought the major
flights, with an average of 244.5 birds per day for 12 days. On
November 1, I recorded 592 Red-tails--as many as 213 in a single
hour; on November 2, 853 Red-tails. Kramer reported diminishing
numbers of Red-tails during the latter part of November, except
for 67 on the 24th. He saw 9 on December 2, and 4 on the next day.
Red-tailed Hawk*
Buteo jamaicensis [Eastern
Red-tailed Hawk]
*Original Source:
Bent, Arthur Cleveland. 1937. Smithsonian Institution United
States National Museum Bulletin 167: 147-165. United States
Government Printing Office
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