General form short and heavy, with the head apparently
disproportionately large, and frequently furnished with ear-like tufts
of feathers. Cavity of the ear, large; eyes, usually large, directed
forwards, and in the greater number of species formed for seeing by
twilight or in the night; bill, nearly concealed by projecting
bristle-like feathers; wings, usually, rather long and formed for rather
slow and noiseless flight, outer edges of primary quills fringed; tail,
various, usually short; legs, generally, rather short, and in all the
species, except those of the Asiatic genus _Ketupa_, Lesson, more or
less feathered to the toes, generally densely; face surrounded by a more
or less perfect disc or circle of short rigid feathers, which circle,
with the large eyes directed forwards, gives to these birds an entirely
peculiar and cat-like expression, indicative of their analogy to the
_Feline_ quadrupeds.
Female larger than the male. General organization adapted to the
destruction of living animals in the night, or in the morning and
evening twilight—midnight appears to be the noon of these birds, at
which they are not disposed to activity.
Species of owls inhabit all parts of the world, most abundantly in
America and Asia. There are about one hundred and forty described
species, of which number, specimens of about one hundred and twenty are
in the collection of the Academy of Natural Sciences of Philadelphia.
The species inhabiting the continent and islands of America are about
forty.