National Museum, 14; Boston Society, 5; Philadelphia Academy, 2; New
York Museum, 1; G. N. Lawrence, 1; R. Ridgway, 2. Total, 25.
_Measurements._
+----+-----------+-----------+---------+---------+-----------+----------+
|Sex.| Wing. | Tail. | Culmen. | Tarsus. |Middle Toe.|Specimens.|
+----+-----------+-----------+---------+---------+-----------+----------+
| ♂ | 9.20–10.70| 6.30–8.00| .60–.68|1.70–1.85| 1.35–1.50| 12 |
+----+-----------+-----------+---------+---------+-----------+----------+
| ♀ |11.00–11.60| 7.80–8.80| .71–.80|1.80–2.00| 1.55–1.70| 9 |
+----+-----------+-----------+---------+---------+-----------+----------+
HABITS. Only two specimens of this Hawk have been taken within the
limits of the United States. One was obtained by Dr. Heermann on the
vast plains of New Mexico, near the United States boundary-line. It
appeared to be flying over the prairies in search of small birds and
mice, at times hovering in the manner of the common Sparrow Hawk
(_Tinnunculus sparverius_). It appears to be resident throughout a large
part of Mexico, and in Central and South America. The other is from the
Rio Pecos of Texas, collected by Dr. W. W. Anderson.
Mr. Darwin, in his Zoölogy of the Voyage of the Beagle, mentions
obtaining one specimen in a small valley on the plains of Patagonia, at
Port Desire, in latitude 47° 44′ south. M. D’Orbigny supposed latitude
34° to be the extreme southern limit of the species. Lieutenant Gilliss
brought specimens from Chile.
Mr. Darwin states that the _F. femoralis_ nests in low bushes, this
corresponding with the observations of Mr. Bishop. He found the
female sitting on her eggs in the beginning of January. According to
M. D’Orbigny, it prefers a dry, open country with scattered bushes,
which Mr. Darwin confirms. Mr. Bishop informs me that he met with this
Hawk in the greatest abundance upon those vast plains of South America
known as the Pampas, in which no trees except the ombû are found, and
that it there nests exclusively on the tops of low bushes, hardly
more than a foot or two from the ground. The bird was not at all shy,
like most Hawks, but was easily approached so nearly as to be readily
recognized.
Mr. Bridges states, in the Proceedings of the London Zoölogical Society
(1843, p. 109), that the _H. femoralis_ is trained in some parts of
South America for the pursuit of smaller gallinaceous birds, and that
it is highly esteemed by the Chilian falconers. It very soon becomes
quite docile, and will even follow its master within a few weeks of its
capture.
I am indebted to Mr. N. H. Bishop for specimens of the eggs of this
Hawk obtained by him on the Pampas. The nest contained but two, and was
built on the top of a low bush or stunted tree, hardly two feet from the
ground. It was constructed, with some pains and elaboration, of withered
grasses and dry leaves.
The eggs measure, one 1.81 inches in length by 1.69 in breadth, the
other 1.78 by 1.63. This does not materially vary from the measurement
given by Darwin. The ground-color of the egg is white. This, however,
is so thickly and so generally studded with fine brown markings, that
the white ground to the eye has a rusty appearance, and its real
hue is hardly distinguishable. Over the entire surface of the egg
is distributed an infinite number of fine dottings, of a color most
nearly approaching a raw terra-sienna brown. Over this again are larger
blotches, lines, and splashes of a handsome shade of vandyke-brown. In
one egg these larger markings are much more frequent than in the other.
The latter is chiefly marked with the finer rusty dottings, and has a
more dingy appearance.