National Museum, 51; Philadelphia Academy, 14; New York Museum, 7;
Boston Society, 5; Museum, Cambridge, 9; Cab. G. N. Lawrence, 1; Coll.
R. Ridgway, 4; Museum W. S. Brewer, 1. Total, 92.
_Measurements._
+----+-----------+-----------+---------+---------+-----------+----------+
|Sex.| Wing. | Tail. | Culmen. | Tarsus. |Middle Toe.|Specimens.|
+----+-----------+-----------+---------+---------+-----------+----------+
| ♂ | 6.45–7.00| 5.70–5.90| .40–.00|1.85–1.95| 1.10–1.20| 30 |
+----+-----------+-----------+---------+---------+-----------+----------+
| ♀ | 7.50–8.80| 6.90–8.20| .50–.60|2.20–2.25| 1.45–1.55| 40 |
+----+-----------+-----------+---------+---------+-----------+----------+
Specimens from different regions vary but little in size. The largest
are 4,198, ♀, San Francisco, Cal., winter, 16,957, ♀, Hudson’s Bay
Territory, and 55,016, ♀, Mazatlan, Mexico, in which the wing ranges
from 8.40 to 8.50, the tail 7.00. The smallest females are 45,826,
Sitka, Alaska, and 11,791, Simiahmoo, W. T., in which the wing measures
about 7.80. A female (32,499) from Orizaba, Mexico, one (8,513) from
Fort Yuma, Cal., and one (17,210) from San Nicholas, Lower California,
have the wing 8.00, which is about the average. The largest males are
54,336, Nulato, Alaska, 58,137, Kodiak, Alaska, 27,067, Yukon, mouth
of Porcupine, and 55,017, Mazatlan, Mexico, in which the wing measures
7.00, the tail 5.60. The smallest males are 5,990, Orange, N. J.,
8,514, Shoalwater Bay, W. T., 21,338, Siskiyou Co., Cal., 37,428,
Orizaba, Mexico, and 5,584, Bridger’s Pass, Utah; in this series the
wing measures 6.50–6.70, the tail 5.40–5.60. A specimen from Costa
Rica measures: wing 6.70, tail 5.35. Thus the variation in size will
be seen to be an individual difference, rather than characteristic of
any region. Some immature specimens from the northwest coast of North
America (as 45,828, ♂, Sitka, Rus. Am., 5,845, ♂, Fort Steilacoom,
W. T., 11,791, Simiahmoo, Puget Sound, and 8,514, Shoalwater Bay,
W. T.) are much darker than others, the brown above inclining to
blackish-sepia; no other differences, however, are observable. An adult
from the Yukon (54,337, ♀) has the rufous bars beneath remarkably faint,
although well defined; another (19,384, ♀, Fort Resolution), in immature
plumage, has the longitudinal markings beneath so faint that they are
scarcely discernible, and the plumage generally has a very worn and
faded appearance. A male in fine plumage (10,759, Fort Bridger, Utah)
has the delicate reddish-rufous beneath so extended as to prevail, and
with scarcely any variegation on the sides and tibiæ; the bars on the
tail, also, are quite obsolete.
HABITS. This species is one of the most common Hawks of North America,
and its geographical range covers the entire continent, from Hudson’s
Bay to Mexico. Sir John Richardson mentions its having been met with
as far to the north as latitude 51°. Drs. Gambel and Heermann, and
others, speak of it as abundant throughout California. Audubon found it
very plentiful as far north as the southern shore of the Gulf of St.
Lawrence. It has been obtained in New Mexico by Mr. McCall, in Mexico
by Mr. Pease, in Washington Territory by Dr. Cooper and Dr. Suckley,
in Alaska by Mr. Dall, at Fort Resolution by Mr. Kennicott, at Fort
Simpson by Mr. B. R. Ross, etc. Messrs. Sclater and Salvin give it
as a rare visitant of Guatemala. It has been ascertained to breed in
Massachusetts, New Jersey, Wisconsin, California, and Pennsylvania, and
it probably does so not only in the intervening States and Territories,
but also in all, not excepting the most southern, Florida, where its
nest was found by Mr. Wurdemann.
[Illustration: _Nisus fuscus._]
Dr. Woodhouse, who frequently observed this bird skimming over the
prairies while in search of its prey, states that its flight is so
peculiar that there is no difficulty in recognizing it, when taken in
connection with its form, short wings, and long tail, being very swift
and irregular in its movements, first high in the air, then close to the
ground, suddenly disappearing among the grass when it has seized the
object of which it was in pursuit.
Mr. Dresser met with this Hawk in Texas, but nowhere south or west of
San Antonio, where it remains through the breeding-season, nesting in
the dense cedar-thickets.
Mr. Audubon regarded it as the very miniature of the Goshawk, in its
irregular, swift, vigorous, varied, and yet often undecided, manner of
flight, and on occasion greatly protracted. When in search of its prey,
it is said to pass over the country, now at a moderate height, now close
over the land, and with a surprising swiftness. It advances by sudden
dashes, and pounces upon the object of its pursuit so suddenly as to
render hopeless any attempt to escape. It has frequently been known
to seize and kill a bird so large that it was unable to carry it, and
had to drop to the ground with it. In one instance Mr. Audubon saw it
strike a Brown Thrush, which it had darted into a thicket of briers to
seize, emerging at the opposite side. As Mr. Audubon ran up, the Hawk
attempted twice to rise with its prey, but was unable to carry it off,
and relinquished it. The Thrush was quite dead, and had evidently been
killed instantly.
Mr. Downes, of Halifax, who speaks of this Hawk as common in Nova
Scotia, breeding all over that province, adds that it does not molest
the poultry-yards, being too weak to attack large prey. But this is not
universally the case. They are frequently destructive both to dove-cots
and to the younger inhabitants of the poultry-yard. Mr. Nuttall narrates
that in the thinly settled parts of Alabama and Georgia it seemed to
abound, and was very destructive to young chickens, a single one having
been known to come regularly every day until it had carried off twenty
or thirty. He was eyewitness to one of its acts of robbery, where, at
noonday and in the near presence of the farmer, the Hawk descended and
carried off one of the chickens. In another instance the same writer
mentions that one of these Hawks, descending with blind eagerness upon
its prey, broke through the glass of the greenhouse at the Cambridge
Botanic Garden, fearlessly passed through a second glass partition, and
was only brought up by a third, when it was caught, though very little
injured.
At times this Hawk is seen to fly high, in a desultory manner, with
quick but irregular movements of the wings, now moving in short and
unequal circles, pausing to examine the objects below, and then again
descending rapidly and following a course only a few feet from the
ground, carefully examining each patch of small bushes in search of
small birds.
Besides the smaller birds, young chickens, and pigeons, this Hawk has
been known to occasionally feed on small reptiles and insects, as also
upon the smaller quadrupeds.
Mr. Audubon speaks of having met with three nests of this species,
and all in different situations. One was in a hole in a rock on the
banks of the Ohio River; another was in the hollow of a broken branch,
near Louisville, Ky., and the third in the forks of a low oak, near
Henderson, Ky. In the first case, the nest was slight, and simply
constructed of a few sticks and some grasses, carelessly interwoven, and
about two feet from the entrance of the hole. In the second instance
there was no nest whatever, but in the third the birds were engaged
in the construction of an elaborate nest. The number of the eggs was
four in one instance, and five in another. He describes them as almost
equally rounded at both ends; their ground-color white, with a livid
tinge, but scarcely discernible amid the numerous markings and blotches
of reddish-chocolate with which they were irregularly covered. In
a nest which was large and elaborately constructed of sticks, and
contained five eggs, found by Dr. H. R. Storer in Concord, Mass.,
there was a single egg which nearly corresponds with this description.
It is, however, the only one among many specimens that at all agrees
with it. This specimen is a little more than usually elongate, and its
ground-color, which is a purplish-white, is nearly concealed by its
blotches of various shades of sepia-brown. In every other instance the
egg is very nearly spherical, the ground-color white, and beautifully
marked with large confluent blotches of sepia, varying in depth from
quite a light to a very dark shade. In one, these confluent markings
form a broad belt around the centre of the egg. In others, they are
chiefly distributed about the larger end. The contrast between the white
ground and the dark confluent dashes of brown is very striking. Except
in size, the eggs of this bird bear a marked resemblance to those of the
Sparrow Hawk of Europe. In a few instances, the brown markings have an
intermixture of red and purple. The egg measures 1.35 by 1.15 inches.
In nearly every instance the nest of this Hawk has been constructed in
trees. It is usually large in proportion to the size of the bird, and
its materials are somewhat elaborately put together; it is composed
chiefly of large sticks and twigs, and the whole platform is covered
with a thin lining of dry leaves, mosses, grass, etc. Mr. John Krider,
of Philadelphia, found a nest in New Jersey, in the vicinity of that
city, which was built on the edge of a high rock.
Mr. Robert Kennicott met with the nest of this species at Fort
Resolution. It was composed entirely of small dry spruce twigs, with the
exception of a half-dozen small flat bits of the scaly outer bark of the
spruce, laid in the bottom, and forming a sort of lining. No feathers or
other softer materials were used. The nest was shallow and broad. The
base was about eighteen inches in diameter, and was about eight feet
from the ground. It was in a small spruce in a thick wood and on high
ground. When disturbed, the female flew off a short distance; but on Mr.
Kennicott’s hiding himself returned and flew near the nest, continually
uttering a harsh rapid note. Near the nest were marks indicating the
place where the male passed the nights perched on a dry stick near the
ground.
Mr. B. R. Ross observed these birds nesting thickly along the cliffs of
the Upper Slave River. They were more rare northward of Fort Simpson
than _F. columbarius_.
Mr. William Street, of Easthampton, informs me that he has found this
Hawk nesting on Mount Tom, where he has known of six of their nests in
one season. In the spring of 1872 he found three nests, on the 24th
and 25th of May. They contained two eggs each. One of these, on the
27th contained three eggs, of which he took one; on the 3d of June two
more eggs had been laid. Two of these were taken, after which the birds
deserted the nest and resorted to an old squirrel’s nest, where they had
four more eggs, depositing one every third day. They arrive at Mount Tom
about the 1st of May. Their nests are made entirely of sticks, larger on
the outside, and smaller within. They usually build in a hemlock-tree,
selecting a thick clump. They are very noisy when they are at work
building their nest, and often betray their presence by their cries.
The younger the pair the more noisy they are. This Hawk appears to live
nearly altogether on small birds. Mr. Street mentions having found ten
or twelve skeletons in a single nest of this species.
Nisus cooperi (BONAP.).
=Var. cooperi=, BONAP.