LADDER-BACKED WOODPECKER.
Picus scalaris, Wagler, Isis, 1829, V, 511 (Mexico).—Bonap. Consp. 1850, 138.—Scl. P. Z. S. 1856, 307.—Sund. Consp. 18.—Baird, Birds N. Am. 1858, 94, pl. xli, f. 1.—Ib. Rep. Mex. Bound. II, 4, pl. iii.—Scl. Cat. 1862, 333.—Cass. P. A. N. S. 1863, 195.—Gray, Cat. 1868, 48.—Heerm. X, c, p. 18.—Cooper, Orn. Cal. 1, 1870, 379. Picus (Dyctiopicus) scalaris, Bon. Consp. Zygod. Aten. Ital. 1854, 8. Dyctiopipo scalaris, Cab. & Hein. Mus. 74. Picus gracilis, Less. Rev. Zoöl. 1839, 90 (Mexico). Picus parvus, Cabot, Boston Jour. N. H. V, 1845, 90 (Sisal, Yucatan). Picus orizabæ, Cassin, Pr. A. N. S. 1863, 196 (Orizaba). Picus bogotus, Cassin, Pr. A. N. S. 1863, 196; Jour. A. N. S. V, 1863, 460, pl. lii, f. 1 (Mex.). Picus bairdi (Scl. MSS.), Malherbe, Mon. Pic. I, 118, t. xxvii, f. 7, 8.—Scl. Cat. 333, (?) P. Z. S. 64, 177 (city of Mex.).—Cab. & Hein. Mus. Hein. IV, 2, 76.—Cassin, Pr. A. N. S. 1863, 196.—Coues, Pr. A. N. S. 1866, 52 (perhaps var. graysoni).—Dresser, Ibis, 1865, 468. Hab. Texas and New Mexico, to Arizona; south through Eastern Mexico to Yucatan. Picus scalaris, var. graysoni, Baird, MSS. Hab. Western Arizona; Western Mexico and Tres Marias.
Sp. Char. Back banded transversely with black and white from nape to rump (not upper tail-coverts). Quills and coverts with spots of white; forming bands on the secondaries. Two white stripes on sides of head. Top of head red, spotted with white. Nasal tufts brown. Beneath brownish-white, with black spots on sides, becoming bands behind. Outer tail-feathers more or less banded. Length, about 6.50; wing, 3.50 to 4.50; tail, about 2.50.
Hab. Guatemala, Mexico, and adjacent southern parts of United States. Localities: Xalapa (Scl. P. Z. S. 1859, 367); Cordova (Scl. 1856, 357); Guatemala (Scl. Ibis, I, 136); Orizaba (Scl. Cat. 333); S. E. Texas (Dresser, Ibis, 1865, 468, breeds); W. Arizona (Coues, P. A. N. S. 1866, 52); Yucatan (Lawr. Ann. N. Y. Lyc. IX, 205).
In the above diagnosis we have endeavored to express the average of characters belonging to a Woodpecker to which many names, based on trifling geographical variations, have been assigned, but which legitimately can be only considered as one species. This is among the smallest of the North American Woodpeckers, and in all its variations the wings are long, reaching as far as the short feathers of the tail. The upper parts generally are black, on the back, rump, and exposed feathers of the wings banded transversely with white, the black bands rather the narrower; the quills and larger coverts spotted with the same on both webs, becoming bands on the innermost secondaries. The upper tail-coverts and two inner tail-feathers on either side are black. The white bands of the back extend all the way up to the neck, without any interscapular interruption. The under parts are of a pale smoky brownish-white, almost with a lilac tinge; on the sides of the breast and belly are a few scattered small but elongated spots. The posterior parts of the sides under the wing and the under tail-coverts are obscurely banded transversely with black. The top of the head, extending from a narrow sooty frontlet at the base of the bill to a short, broad nuchal crest, is crimson in the male, each feather with a white spot between the
crimson and the dark brown base of the feathers. The brown nasal tuft is scarcely different from the feathers of the forehead.
In a large series of specimens of this species, from a wide area of distribution, considerable differences are appreciable in size, but fewer in coloration than might be expected. Yucatan birds are the least (Picus parvus, Cabot; vagatus, Cassin), the wing measuring 3.30 inches. Those from Southern Mexico are but little larger (wing, 3.60). In Northern Mexico the wing is nearly 4 inches; in New Mexico it is 4.30. The markings vary but little. The black and white bands on the back are about of equal width, but sometimes one, sometimes the other, appears the larger; the more eastern have, perhaps, the most white. The pattern on the tail is quite constant. Thus, assuming the three outer feathers to be white, banded with black, the outermost may be said to have seven transverse bars of black, of which the terminal four (sometimes five) are distinct and perfect, the basal three (or two) confluent into one on the inner web (the extreme base of the feather white). The next feather has, perhaps, the same number of dark bands, but here only two (sometimes three) are continuous and complete; the innermost united together, the outer showing as scallops. The third feather has no continuous bands (or only one), all the inner portions being fused; the outer mere scallops, sometimes an oblique edging; generally, however, the interspaces of the dark bands are more or less distinctly traceable through their dusky suffusion, especially on the inner web of the outer feather. The number of free bands thus varies slightly, but the general pattern is the same. This condition prevails in nearly all the specimens before us from Yucatan and Mexico (in only one specimen from Arizona, and one or two from Texas), and is probably the typical scalaris of Wagler.
In specimens from the Rio Grande and across to Arizona the seven bands of the outer feather are frequently continuous and complete on both webs to the base, a slight suffusion only indicating the tendency to union in the inner web. The other feathers are much as described, except that the white interspaces of the black scallops penetrate deeper towards the shaft. This is perhaps the race to which the name of P. bairdi has been applied. We do not find, however, any decided reduction in the amount of red on the anterior portion of the head, as stated for this species (perhaps it is less continuous towards the front), except in immature birds; young females possibly losing the immature red of the crown, as with typical scalaris.
A third type of tail-marking is seen in specimens from the Pacific coast, and from the Tres Marias especially; also in some skins from Southwestern Arizona. Here the extreme forehead is black, with white spots; the red of the crown not so continuous anteriorly even as in the last-mentioned race. The general pattern of tail is as described, and the bars on the inner webs are also confluent towards the base, but we have only two or three transverse bars at the end of the outer feathers; the rest of outer web entirely white, this color also invading the inner. The second feather is similarly
marked, sometimes with only one spot on outer web; the third has the black scallops restricted. This may be called var. graysoni, as most specimens in the Smithsonian collection were furnished by Colonel Grayson. The size is equal to the largest typical scalaris.