target="_blank" rel="nofollow" href="#i000008030000.jpg"/>414.
7899.
773.
628.
7897.
437.
7449. Strix pratincola. Natural size.
4886. Otus wilsonianus. Natural size.
7272. Scotiaptex cinereum. Two thirds.
7899. Nyctale richardsoni. Natural size.
414. Scops asio. Natural size.
773. Bubo virginianus. Two thirds.
628. Nyctea nivea. Two thirds.
7897. Surnia ulula. Natural size.
428. Glaucidium ferrugineum. Natural size.
437. Spheotyto hypogæa. Natural size.
7449.
4886.
7272.
7897.
414.
628.
773.
7899.
437.
428.
7449. Strix pratincola. Natural size.
4886. Otus wilsonianus. Natural size.
7272. Scotiaptex cinereum. Two thirds.
7899. Nyctale richardsoni. Natural size.
414. Scops asio. Natural size.
773. Bubo virginianus. Two thirds.
628. Nyctea nivea. Two thirds.
7897. Surnia ulula. Natural size.
428. Glaucidium ferrugineum. Natural size.
437. Spheotyto hypogæa. Natural size.
7449.
4886.
7272.
7899.
733.
628.
7897.
414.
437.
428.
7449. Strix pratincola.
4886. Otus wilsonianus.
7272. Scotiaptex cinereum.
7899. Nyctale richardsoni.
414. Scops asio.
773. Bubo virginianus.
628. Nyctea nivea.
7897. Surnia ulula.
428. Glaucidium ferrugineum.
437. Spheotyto hypogæa.
(All natural size.)
12088.
504.
49808.
504.
A.
49808.
12088. Nyctea nivea. (Ear copied from Swainson, F. B. A)
504. Scotiaptex cinereum.
49808. Surnia ulula. (Ear copied from Swainson.)
A. Brachyotus “cassinii.” (Left ear and nostril, from fresh specimen.)
Family FALCONIDÆ.—The Falcons
Char. Eyes directed laterally, and eyelids provided with lashes. Toes invariably naked, and tarsus usually naked and scutellate (feathered only in Aquila and Archibuteo). Outer toe not reversible (except in Pandion). Head never with ear-tufts, and never wholly naked (except in the Vulturinæ, of the Old World).
The above characters are about the only readily observable points in the external anatomy in which the Falconidæ differ strikingly from the Strigidæ and Cathartidæ, and may serve to distinguish the birds of this family from those of the two others. The osteological characters, however, as expressed on page 1328, are more decided and important in a taxonomic point of view, and serve to separate the Hawk family as a well-defined group.
In the following treatment of the North American Falconidæ, I confine that part relating to the systematic arrangement strictly to the species embraced within the province of our work, for the reason that in a forthcoming monograph of all the American species I hope to present a systematic classification based upon the species of the whole world. All preliminary details regarding the general characteristics and distinctive peculiarities of the
