National Museum, 44; Philadelphia Academy, 18; Boston Society, 6; Coll.
G. N. Lawrence, 2; R. Ridgway, 5. Total, 75.
_Measurements._
+----+-----------+-----------+---------+---------+-----------+-----------+
|Sex.| Wing. | Tail. | Culmen. | Tarsus. |Middle Toe.| Specimens.|
+----+-----------+-----------+---------+---------+-----------+-----------+
| ♂ |13.50–16.00| 9.50–10.00| .90–1.10|2.90–3.30| 1.70–1.80| 30 N. Am.|
+----+-----------+-----------+---------+---------+-----------+-----------+
| ♀ |16.00–17.25| 9.50–11.30|1.00–1.08|3.30–3.40| 1.80–1.95| 16 N. Am.|
+----+-----------+-----------+---------+---------+-----------+-----------+
| ♂ |13.25–14.00| 9.00–0.00|1.00–0.00|3.30–0.00| 1.80–0.00|2 Jamaican.|
+----+-----------+-----------+---------+---------+-----------+-----------+
| ♀ | 14.50–0.00| 9.00–0.00|1.10–0.00|3.25–0.00| 1.75–0.00|1 Jamaican.|
+----+-----------+-----------+---------+---------+-----------+-----------+
| ♂ | 15.50–0.00| 9.50–0.00|1.15–0.00|3.10–0.00| 1.85–0.00| 1 Cuban.|
+----+-----------+-----------+---------+---------+-----------+-----------+
A large collection of specimens of this race presents a series
connecting _borealis_ with the black form known as “_calurus_”; every
possible condition between the two being indicated in the range of
individual variation. The lightest styles as distinguished from var.
_borealis_ always have the tibiæ barred with rufous; the crissum, also,
is generally barred, on the throat the blackish-brown predominates, and
the tail has more or less perfect bars to the roots of the feathers;
generally, however, these are merely indicated by projections from the
shafts.
The extreme condition of this is the melanistic form which Mr. Cassin
described as “_Buteo calurus_”; the darkest example of which (5,481,
Petaluma, Cal.; E. Samuels) is entirely blackish-brown, wings and
scapulars with feathers somewhat paler at tips; breast inclining to dark
sepia-brown, the feathers with black shaft-streaks; tibial feathers
faintly tipped with pale grayish-brown; lower tail-coverts tipped and
barred with rufous; upper tail-coverts deep rufous barred with black;
tail deep chestnut-rufous, the subterminal black band very broad, and
anterior to this are nine or ten imperfect narrower black bands.
These fuliginous examples have always a more or less appreciably lighter
pectoral area, corresponding to the white of this region seen in the
lighter styles.
Of this race, almost each individual has its own characteristic
markings, and scarcely two are to be found alike in a very large series
from Western North America. All the specimens from the Rocky Mountains
to the Pacific, and from the table-lands of Mexico, as well as from Cuba
and Jamaica, are referrible to this variety, although we are not aware
that in the latter region the bird ever becomes black. In the latter
island this species (as is also the case with many other birds) seems to
be remarkably subject to albinism. In the peninsula of Lower California
it is replaced by the var. _lucasanus_, and in Central America by
the very different var. _costaricensis_; from both of which it may
be distinguished by the numerous transverse rufous bars crossing the
posterior under parts, which character serves also to distinguish the
lightest examples from the eastern typical _borealis_.
A specimen (50,761; Colonel Grayson) from the Socorro Island, S. W.
Mexico, is like some Fort Tejon specimens.
No. 41,759 (immature), Merida, Yucatan (Dr. Schott), is remarkably
light colored, or, rather, is unusually variegated with whitish above;
the tail, also, is almost white; the bands, however, very conspicuous.
The lower parts are as thickly spotted as in specimens from Washington
Territory.
The young bird of this western style is as different from that of the
eastern as is the adult, and the essential differences are about the
same,—i.e. darker colors, or a predominance, or, rather, increase in
size, of the dark markings. The numerous heavy transverse spots on
the tibia constitute a persistent feature of the young of the var.
_calurus_, as compared with the almost, or perfectly, immaculate white
of those in var. _borealis_.
It being certain that the _Buteo montanus_ of Nuttall is really the _B.
swainsoni_, and not the variety of _borealis_ so called by Mr. Cassin,
it becomes necessary to drop this name in connection with the present
bird, and transfer it as a synonyme to _swainsoni_. In its place, Mr.
Cassin’s name _calurus_ must be substituted, under which was described
the melanistic condition of the present variety of _borealis_.
In describing his _B. montanus_, Nuttall cites Audubon’s plate of
“_Falco buteo_,” which, of course, is a name by which the _B. swainsoni_
was first designated before it was distinguished from the _B. vulgaris_
of Europe. Audubon’s plate represents, unmistakably, the adult female of
the _Buteo swainsoni_.
HABITS. The well-known Red-tailed Hawk is widely distributed throughout
North America from the West Indies and Central America to the Arctic
regions, and from the Atlantic to the Pacific.
According to Sir John Richardson, it is common in the fur countries,
which it visits in summer, and where a few are known to breed. Specimens
were taken by his party on the Rocky Mountains, the plains of the
Saskatchewan, and at the York factory. These were all between the 53d
and the 57th parallels of latitude.
[Illustration: _Buteo borealis_ (adult).]
Mr. Salvin cites it as generally and plentifully distributed throughout
Guatemala, from whence numerous examples in all stages of plumage, from
the young to the adult, were transmitted by Mr. Skinner. It was also
found at Dueñas by him. Mr. Swainson states that this Hawk was taken on
the plains of Mexico by Mr. Taylor. A single specimen was received by
Mr. Lawrence from Panama. Mr. Gosse states that it is the most common
bird of this family in Jamaica, where it is a resident, and where it
breeds. Mr. Lembeye and Dr. Gundlach both include it in their lists of
the birds of Cuba, and the latter marks it as breeding in that island.
It has been observed in Florida by Mr. Allen, and is not uncommon in all
the New England States, where it is resident throughout the year. In the
Southern States it is most abundant in the winter months.
Specimens of this bird are recorded in the government reports as
obtained from the Yellowstone, from the Pecos River in Texas, and from
Fort Fillmore in New Mexico. Mr. Dresser found it common throughout
all of Texas in all seasons of the year, breeding in all parts, but
preferring the heavily timbered country. He obtained its eggs from
Systerdale and from the Medina River.
This Hawk is a strong and powerful bird, with a firm, steady, and
protracted flight, frequently at a great elevation, and often moving
quite a distance without any apparent motion of the wings. It is said
to generally descend upon its prey from some fixed position, as the
branch of a tree, and rarely to dart upon it when flying. It is a
cautious bird, and rarely ventures near a house for poultry except when
the dwelling is isolated and near its own haunts. It preys chiefly upon
small quadrupeds, small birds, and reptiles. It usually darts upon a
snake from the branch of a tree, and seizing it near the head bears it
writhing through the air. In the valley of the Saskatchewan, Richardson
states that it watches for the marmots, and when one imprudently
ventures from its burrow, darts upon it, bears it a short distance off,
and tears it to pieces.
As they fly, these birds utter a very peculiar and unpleasantly harsh
cry or scream, which they repeat very frequently. Capt. Blakiston
observed this at the Red River settlement, and speaks of it as the
Squealing Hawk.
Though said to be thus generally cautious in exposing itself to danger
in approaching a poultry-yard, it is not always thus cautious. Mr.
Downes mentions an instance where one of these birds entered a garden in
Halifax to pounce upon a tame Crow, and was captured alive by the owner.
Mr. Audubon states that after rearing their young they no longer
remain mated, but separate and evince rather jealous hostility to each
other than good-will. When one has taken any prey in sight of another,
the latter will pursue and struggle with it for possession of the
plunder. In these fights they scream vociferously while struggling for
possession.
In the Southern States these Hawks begin to build in February; in the
Middle States, from March the 24th to April 15th; and in New England
usually from April to May. They construct a large nest, composed
externally of coarse sticks and twigs, and lined with dried grasses,
moss, and leaves, built for the most part in the fork of a lofty tree.
The eggs are usually four in number.
Mr. Augustus Fowler of Danvers, who is familiar with the habits of this
bird, writes me that in Massachusetts they usually begin to build their
nests about the first of April, selecting some tall tree near the middle
of the woods, the branches of which form a crotch near its trunk. To
this chosen spot the female carries a sufficient quantity of sticks for
its outside (the male taking no very active part in the matter), and for
its inside she uses the bark from the dead branches of the chestnut,
which she beats and pecks to pieces with her bill, making it soft and
pliable, or gathers the fallen leaves of the pine, or some other soft
material, which she finds conveniently, as a lining, which is about one
inch in thickness. It is thirteen inches in diameter from outside to
outside, and seven inches in diameter on the inside, while its depth
is two and a half inches. The female usually lays five eggs, which are
spherical, of a dirty-white color, and marked with large blotches of
brown; on some they cover almost the whole egg, while others are marked
mostly on the large end, and some even of the same nest are so faintly
marked as to appear almost wholly white. They are 2.12 inches in length
and 1.95 in diameter.
In Jamaica, according to Mr. March, these Hawks do not confine
themselves to any particular mode or place for breeding, height seeming
to be their chief object. He has found their nest in a quite accessible
tree, not more than twenty feet from the ground, and near a frequented
path. In another instance a pair nested for several years on the roof
of the turret of the belfry of the Spanishtown Cathedral church. The
nest he describes as a platform of dry sticks, more than a foot across
and two or three inches thick. The bed of the nest is about six inches
across and two deep, of fine inner bark, grass, and leaves, containing
four or five eggs, nearly spherical, measuring 2.25 by 2.75 inches, of a
dirty or clayish white, dashed with blotches and spots of vandyke-brown
and umber, often running with a light shade into the ground-color.
The eggs of the Red-tail exhibit great variations in nearly every
respect except their shape, which is pretty uniformly a spheroidal-oval.
Their ground-color varies from white to a dingy rusty drab, their
markings vary greatly in colors, shades, size, frequency, and
distribution. In some the markings are small, few, and light, and the
egg appears to be of an almost homogeneous brownish-white. In others
the ground is completely concealed by large and confluent blotches of
deep and dark purplish-brown, burnt umber, and a peculiar shade known as
Dutch umber. In some the markings are distributed in fine and frequent
granulations, diffused over the entire surface of the egg, producing
the effect of a color of uniform umber brown, through which the ground
of yellowish-white can only be traced by a magnifying-glass. Four eggs
in my cabinet average 2.22 inches in length by 1.72 in breadth. The
largest egg measures 2.55 by 1.90 inches; the smallest, 2.10 by 1.70.
The capacity of the largest to the smallest is nearly as five to four.
The season in which this Hawk deposits its eggs varies considerably. Mr.
Jackson of West Chester, Penn., gives March 24 the earliest, and April
15 the latest, in which he has met with its fresh eggs.
Mr. Ridgway obtained two eggs of this Hawk at Mount Carmel, Ill., on
the 6th of March, the nest having been commenced early in February. It
was placed on the summit of a black-gum tree (_Nyssa multiflora_), and
rested upon the topmost branches, about ninety feet from the ground.
It was lined with corn-husks, gathered from a field close by. The eggs
(No. 12,740, S. I. Collection) measure, respectively, 2.45 and 2.50 in
length, by 1.95 and 2.00 in breadth. Their color is plain bluish-white,
entirely free from markings of any kind.
In California, the var. _calurus_ is stated to be common in all parts
of the State not destitute of trees, and to reside permanently wherever
found, pairing only during the breeding-season. They prey upon hares
and other small quadrupeds, upon smaller birds, and upon reptiles.
Dr. Cooper states that at times, when food is plenty, they become
excessively fat. They are known to occasionally seize a fowl from the
farm-yard. During the middle of the day, in the cold weather, they are
said to soar very high in the air, and occasionally to disappear also in
the manner of their eastern relatives, the _Buteo borealis_. They are
said to be abundant and resident species in Washington Territory, having
been found by Dr. Suckley quite numerous at Puget Sound, but scarcer
on the Upper Columbia, east of the Cascade Mountains. It seems to be
more daring than is common with the _borealis_, for Dr. Suckley states
that while he was stationed at Fort Steilacoom he noticed that the
poultry-yards were as much harassed by this Hawk as by the Goshawk, not
hesitating to seize poultry from the very doors of the dwelling-houses.
Dr. Kennerly states that this Hawk was met with by him between the coast
of Texas at Indianola, and the Rio Grande at El Paso del Norte. It
seemed to feed indifferently upon reptiles, particularly lizards, and
the smaller quadrupeds and birds.
Dr. Cooper states that the nests of this species are numerous in the
valleys and on the lower mountains of California. They are generally
built in the forks of a sycamore or other large trees, and formed of
twigs pretty finely constructed, and with a very distinct cavity. Eggs,
taken by Dr. Cooper near San Diego, were laid about the 20th of March,
and were three in number. They measured 2.28 by 1.76 inches, were
of a dull yellowish-white, with faint brown spots. While Dr. Cooper
was climbing to the nest, the old birds darted towards him from a
neighboring bluff, but when within a few feet of his head they turned
away and did not attempt to make an assault.
Two eggs belonging to the variety _calurus_ were obtained by Mr. E.
Samuels near Petaluma, Cal., in 1856; measure 2.31 inches in length by
1.87 in breadth. The shape of one egg is an almost exact ovoid, slightly
tending to a spheroid, one end being hardly perceptibly larger than the
other. Its ground-color is a very light buff, the spottings and markings
giving to it the effect of a yellowish-white. It is marked over the
entire surface with blotches, dashes, and lines of a light tint of a
brown tending to vandyke. These are mixed with markings of a lighter
purplish-brown. The markings, of both shades, are chiefly oblong in
shape, and run with the length of the egg. They bear no resemblance to
any eggs of the _B. borealis_ that I have ever seen, and are unlike
those of other Hawks so far as I am aware. It was built on the top of
a large evergreen-oak, at least seventy feet from the ground, and was
constructed entirely of large, coarse sticks, lined with a few stray
feathers. The male bird was shot as it flew from the nest, which was so
hidden by the thick branches that it would have escaped detection.
The black form of this species was first described by Mr. Cassin as
_Buteo calurus_, in 1855, from a specimen procured by Dr. Henry near
Fort Webster, New Mexico. In this plumage it was afterwards met with
by Mr. Emanuel Samuels, near Petaluma, in California, who found it
breeding, and was fortunate enough to secure the parent bird on its
nest.
The nest was built near the top of an evergreen-oak, at the height of
about sixty feet from the ground, and contained two eggs just on the
point of hatching. It was constructed of sticks, and was lined with
moss. Both birds were about the spot. The male bird, manifesting much
more courage than his mate in resistance to the intruders, was shot. The
female was wounded, but escaped.
One of these eggs measures 2.25 inches in length by 1.79 in breadth.
Its capacity is considerably less than that of the specimens just
described; its shape is a much more oblong-oval; one end is evidently
more pointed than the other. Its ground-color is a dirty cream-white,
covered, chiefly at the larger end, with blotches and smaller markings
of a dark shade of a brown almost exactly corresponding with that known
as vandyke-brown, with smaller markings and spottings of a lighter shade
of the same. The latter are distributed at intervals over its entire
surface.
A nest, found by Mr. Xantus near Fort Tejon, is stated by him to have
been found in a swamp. It was built in a water-oak, was about fifteen
feet from the ground. The nest was very large and was built of coarse
sticks. It contained four eggs.
Buteo harlani (AUDUBON).