HYPOTHETICAL LIST. 755 



except by the expert. In all essential respects the Loggerhead has the 

 habits and characteristics of the Migrant Shrike and the White-rump. 



TECHNICAL DESCRIPTION. 



Bill strongly hooked, wing less than 4 inches, tail averaging longer than wing, third 

 and fourth primaries about equal, the foiu-th usually a little the longest. 



Adult (sexes essentially alike) : Upper 2Jarts slate-gray to ash-gray, very little if at all 

 paler on the rump and upper tail-coverts; nasal bristles, lores, and broad stripe around and 

 behind the eye, clear black, the black continuous across the front of forehead; a faint 

 white or grayish line between this black area and the gray of the top of head; under parts 

 nearly pure white, sometimes faintly shaded with grayish on sides of breast and body or 

 (in immature birds) shghtly tinged with reddish; wings black, with -a conspicuous white 

 patch near the middle of the primaries, and most of the secondaries and tertiarics tipped 

 with white; scapulars mostly pure white; central tail-feathers black, outer tail-fcatluMs 

 pure white or with a small black area near base, other tail feathers black broadly tip])e(l 

 with white; bill and feet entirely black; iris brown. Young: Similar to adults, but all the 

 gray and white areas strongly washed with brownish; back and under |)arts with numerous 

 wa\'y cross-lines of brown or dusky; greater wing-coverts tipped with rusty or buffy. 



Length 8.50 to 9.50 inches; wing of male 3.75 to 3.90, of female 3.66 to 3.78; tail of male 

 3.89 to 4.15, of female 3.87 to 3.97; culmen about .59 (Wm. Palmer). 



White-rumped Shrike. Lanius ludovicianus excubitorides Sumns. (622a) 



Separable from the Loggerhead and Migrant Shrike only by the expert, 

 and with difficulty; often not separable at all. The Migrant Shrike is 

 said to have "darker, duller plumage, especially beneath, to be stouter and 

 longer, and to have larger bill, tarsi and feet." (Palmer, Auk, XV, p. 251). 



It seems doubtful whether the true White-rumped Shrike, as distinct 

 from the Migrant Shrike, ever occurs in Michigan. For the present at 

 least we may relegate this species to the doubtful list. 



Its natural habitat is from the eastern border of the Plains to the Pacific, 

 and from jNlanitolia and the Plains of the Saskatchewan south over the 

 tablelands of Mexico. 



Panila Warbler. Compsothlypis americana americana (Linn.). (648) 



The typical form of the Parula or Blue Yellow-backed Warbler does 

 not seem, to be found in Michigan, being replaced by the northern form, 

 C. americana usnece Specimens intermediate between the two forms 

 occur in northern Indiana according to Butler (Birds of Indiana, 1897, 

 p. 1040), and possibly some of these occur in southern IMichigan, but all 

 the specimens we have seen appear to belong to the northei'n subspecies. 



Yellow-throated Warbler. Dendroica dominica dominica (Linn.). (663) 



Very similar to tiic Sycamore Wai'bler (No. 2S0) which has been mistaken 

 for it several times. The latter is readily disci-iminated with specimen 

 in hand, since the stripe over the eye is almost or quite pmv white, while 

 it is distinctly yellow anteriorly in the Yellow-throated Warbler. The 

 latter is a bird of the Southern Atlantic States, and there is no authentic 

 record of its occurrence in Michignn. 



Brown-headed Nuthatch. Sitta pusilla Lafli. (729) 



Sinallci- than llic Kod-lx'llicd Nullialch, with tlie top and back of head 

 grayish-brown; no wliite over the eye. but a wliitisli patcli on the nape. 



