The North American Towhees of the maculatus group are at present involved in much confusion. The trouble seems to be that each locality furnishes a race of its own which either possesses certain slight individual characteristics, or combines, in varying degrees, the characters of two or more recognized forms. The case, however, is not peculiar; for to a greater or less extent the same state of things obtains among the Song Sparrows, Shore Larks, and several other species, in which the forces of evolution are still actively working.
79. Pipilo chlorurus (Towns.) Baird. Green-tailed Towhee.—Several specimens taken late in April. “Not common; usually found in low brush.”
80. Pipilo fuscus mesoleucus (Baird) Ridgw. Cañon Towhee.—“Common in rocky localities on plains, and in valleys.” A nest containing three eggs was taken June 15 at a point about twenty-five miles north of Tucson. The eggs are grayish-white with numerous, short, zigzag lines of black about the larger end and occasional spots or dashes of brown and dull lavender scattered over the general surface of the shell. They measure respectively .91 × .69, .94 × .69, and .92 × .69. The nest, which was placed about four feet above the ground in a “cat-claw” mesquite, is firmly and rather compactly built of fibrous shreds from the stalks of herbaceous plants, with a few twigs and whole stems supporting the outside, and a scanty lining of horse-hair. Its external diameter is about five inches; its depth two. The cavity is two inches wide and one and a half deep. Both nest and eggs differ somewhat from California examples of crissalis in my collection, the eggs being smaller and whiter, the nest softer and more compact.
177, ♂ ad., Tombstone, April 7. Length, 8.80; extent, 11.60. “Iris light brown.”
186, ♀ ad., Tombstone, April 9. Length, 8.10; extent, 10.90; wing 3.50; tail, 4.15.
416, ♂ ad., Santa Rita Mountains, May 20. Length, 8.50; extent, 11.50; wing, 3.73; tail, 4.45.
81. Pipilo aberti Baird. Abert’s Towhee.—“I have found this species common along the Colorado and Gila Rivers, and I took several on the San Pedro in December, 1880. They appear to be restricted to the vicinity of streams and usually to thick brush, although they frequent trees more than most of the members of this genus. I have seen them hunting insects in the bark of large trees in a manner similar to that of Wrens. They are rather shy. The usual note is a sharp chirp. The song is difficult to describe; it is rapid and near the middle rises to a higher key, quickly falling again and ending on the initial note. The nest is rather bulky; it is sometimes built in bushes near the ground, and again in trees. I found one in a bunch of mistletoe at a height of at least thirty feet.”
A nest found May 28, at Tucson, was built on the top of a mesquite stump, where it was kept in place by the surrounding sprouts. It contained three fresh eggs which measure respectively .91 × .72, .92 × .72, and .90 × .71. They are elliptical in shape, and in the character and distribution of their markings they resemble the above described eggs of P. mesoleucus from which, however, they differ in having a faint but decided bluish cast. The nest is large and loosely built. It is composed mainly of broad strips or ribbons of bark with which are mingled small, pliant twigs and the green stems and leaves of the mesquite(?). The whole structure is homogeneous and, strictly speaking, it has no lining, but the materials surrounding the cavity are rather softer than the rest, while they are arranged with some regard to smoothness. The external diameter of this nest is about seven inches; its depth three. The cavity is three inches wide and two deep.
Juv., first plumage (No. 520, Tucson, June 10). Above uniform light brown; wing-coverts, outer edges of the inner secondaries and a narrow tipping on the tail, brownish-ochraceous; beneath brownish-fulvous with an ochraceous tinge on the throat, abdomen, and crissum, and a broad band of coarse but obscure black spots extending across the breast; head markings as in the adult, but duller.
Eight specimens were collected. “Iris light brown; bill brownish horn-color above, bluish beneath; legs brown.”