A History of North American Birds, Land Birds. Volume 3. Robert Ridgway
The bird was very fierce, and fought me with her wings and beak, uttering all the while a long shrill note, resembling a file drawn across the teeth of a saw. I supplied her with eleven full-grown mice, which she devoured during the first thirty-six hours of her confinement. It is said to place a small nest of feathers at the end of the hole, in which are deposited five white eggs.”
The eggs of the var. cunicularia are of a rounded-oval shape, more obtuse at one end than at the other, measure 1.30 inches in length by 1.05 in breadth, and are of a uniform white color, with a slightly bluish tinge.
6885 ½ nat. size.
Strix pratincola. (See page 10.)
The egg of the A. hypogæa is of a rounded-oval shape, equally obtuse at either end, and averages 1.35 inches in length by 1.13 in breadth, and is of a uniform clear white color. This description is taken from an egg obtained by Mr. E. S. Holden near Stockton in California. Captain Bendire writes that he has found as many as nine, and once even ten, eggs in the nest of the North American species.
NOTE
The crania of the Owls present many features of interest, which may serve a good purpose in the definition of the sections and the genera, and to which attention has been occasionally called in the preceding pages. The tendency to asymmetry is especially marked in some species, and the better to illustrate this and other features we append several plates, in which the corresponding views are placed side by side.39 The figures and accompanying lettering tell their own story, without any necessity of a labored description.
Syrnium aluco (copied from Kaup).
Athene noctua (from Kaup).
Nyctale richardsoni.
7449.
428.
4886.
7272.
7899.
414.
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.
428.
7449.
4886.
7272.
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.
We give, above, three well-marked illustrations of asymmetry: two relating to the auditory apparatus of the two sides of the head, and one of opposite sides of the skull.