BIRD3 — LANUDAE COLLYRIO EXCITBITOROIDES. 327 



COLLYRIO EXCUIUTOROIDES, Baird. 



AVbitc-rumpcd Shrike. 

 Lanius ueubitoroides, Swainsok, F. Bor. Am. II, 1831, 115.— GAMnr.i., Pr. A. N. Sc. Ill, 1847, 200. 



Sp. Cb. — Above ratlior liglit pure bluish asli. Foroliead, sides of crown, scapulars, and upper tail covorU, lioary wliitisli 

 Boncatli phiiu whitish. Win^ and tail black ; the former witli a wliito patch at base of primaries a«l tips of small quills ; tho 

 lutlor with tho lateral feathers tipped with white, and this extending broadly at the base. Bill tlirongliout pitch black. A 

 continuous black stripe from the bill throiigli and behind the eye. Lcngtii, 8.75 or 9 inches ; winij, 3.95 ; tail, 4.35. 



Ilab. — .^li^souri plains and fur countries to Pacific coast. Kastward into Wisconsin, Illinois, and Michigan. (?) 



Head and body above ashy blue, the forehead slightly hoary ; the lower part of rump and 

 upper tail coverts, with the outer scapulars, almost white. Beneath pure white without bands ; 

 the sides very slightly touched with ashy. Wings and tail black ; the primaries with a band of 

 ■white at the base, showing externally as a patch in the wing ; the white extending obliquely a 

 little further on the inner than the outer web. The tertiaries and secondaries are paler on the 

 outer portion of the inner web towards the base, but not abruptly white. The secondar'es, 

 tertials, and inner primaries tipped with white. All the feathers of the tail, except the 

 innermost, are tipped with white, the amount diminishing from the exterior ; the outer feather 

 is, in fact, entirely white, except a patch an inch long on the inner web covered by the tail 

 coverts, and there is a white patch at the base of all the others, except tlie middle. A narrow 

 band on the forehead, including the feathers along the base of the bill, and passing backwards 

 over the lores, eyes, and auriculars, black, this color involving the upper eyelid. This is 

 bordered above by a hoary tinge in the gray of the crown. 



The young differ chiefly in a strong tendency to waved, dark lines in the plumage of the 

 upper and under surfaces. There is also a decided indication of reddish brown in the ground 

 color. The female is smaller, and sometimes has the under mandible paler at the base. 



This species is similar in appearance to C. ludovicianus, but differs in several jioiuts. The 

 ash of the upper parts is decidedly lighter, the rump generally almost white, instead of nearly 

 like the back. The white at the base of the tail feathers is much more extended, reaching 

 ■within lialf an inch or less of the tips of the coverts. There is also a good deal of white on 

 the secondaries, visible from below, not seen in ludovicianus. 



In a large series of specimens I find diflerences, which, however, I can scarcely consider as 

 specific. There is some variation in the ground color, but this is almost always lighter than 

 in C. ludovicianus. The hoary tinge on the forehead and alongside the crown is sometimes 

 entirely wanting ; and in the most strongly marked specimen (from Presidio) the under parts 

 are strongly tinged with ash. The amount of black on the outer tail feather is sometimes but 

 little more than in ludovicianus. Sometimes the black band across the base of the bill is 

 distinctly visible, at others it is wanting, leaving the hoary bluish of the head. 



Tlie specimens before me from Wisconsin and Michigan are all immature and not well 

 characterized ; I am, however, inclined to refer them to C. excuhitoroides. An adult, No. 10172, 

 however, from south Illinois, is exceedingly like specimens from the plains, except that the 

 rump is not quite so whitish. 



In the collection of the Philadelphia Academy is a shrike collected in California by Dr. Gambel, 

 ■which exhibits some peculiarities. The ash color above is darker than in excuhitoroides, and there 

 is no hoary on the forehead and sides of the crown at all. The tail coverts are very nearly the 

 color of the back, not whitish. The black of the sides of the head extends further down, to a 



