Hab. Northern regions of both continents. Montreal (Dr. Hall); Maine, Massachusetts (Dr. Brewer); Wisconsin (Dr. Hoy); Northern Ohio (Prof. Kirtland); Vermont (Mr. Z. Thompson); Hudson’s Bay (Dr. Richardson); New Jersey (Mr. Harris). Spec. in Mus. Acad., Philada. Obs. This remarkable species, which partakes of the characters of both an Owl and a Hawk, is of very rare occurrence in the Middle States of this Union, though abundant in the northern regions of America, and occasionally met with in the Northern States. It is in a great measure diurnal in its habits, venturing abroad boldly in daylight. Careful examination of numerous American and European specimens has not enabled us to detect any differences. This bird was undoubtedly meant by Linnæus in his description of _Strix ulula_. The name applied to it by various authors, _Strix funerea_, is properly applicable to the European species, to which Gmelin gave the name _Strix Tengmalmi_. The descriptions now given embrace all the species of Owls the existence of which in America north of Mexico is satisfactorily demonstrated; though in the succeeding pages various others will be enumerated as obscure or little known. All the species enumerated in the preceding synopsis, except _Nyctale albifrons_, are known to be of common occurrence in some part of that portion of this continent included in our limits; and specimens of a majority of them can be obtained generally in the course of a single winter in the markets of either of the larger cities, being brought for sale from the country, as is the case with the Falcons, and also all the larger and most common wading and swimming birds. The study of the habits of Owls is, however, attended with peculiar difficulties, on account of their nocturnal habits; and it is not therefore remarkable that questions respecting common species are yet to be regarded as unsettled. The identity, for instance, of _Scops asio_ and _Scops nævia_, is by no means universally admitted; nor, if identical, is the change in the colors of their plumage sufficiently well understood. Gentlemen well acquainted with American ornithology, and in whose opinions we have the highest confidence (as, for instance, Thomas B. Wilson, M. D., and Samuel W. Woodhouse, M. D., of Philadelphia), are strongly disposed to doubt that they are identical.