yio Field Museum of Natural History — Zoology, Vol. IX 



the Olive-backed Thrush but differs in having the breast and sides of 

 the throat only faintly tinged with buif, and in its grayish lores and 

 whitish eye ring. 



361a. Hylocichla aliciae bicknelli Ridgw. 



Bicknell's Thrush. 



Turdus alicicB bicknelli (Ridgw.), A. O. U. Check List, 1895, p. 317. 



Distr.: Eastern United States; breeding on mountains of New 

 England from Massachusetts northward and in Nova Scotia; south 

 in winter to southeastern states and Bahamas; accidental in Illinois. 



Special characters: Similar to H. alicice but smaller; the tail de- 

 cidedly shorter and the upper parts averaging browner. 



Wing, 3.40 to 3.80; tail, 2.60 to 2.88. 



The only record of the occurrence of Bicknell's Thrush within 

 our limits is that given by Ridgway, who states: "A single speci- 

 men was obtained at Warsaw, Illinois, on the 24th of May, 1884, by 

 Mr. Chas. K. Worthen, thus considerably extending its known range 

 and adding it to the fauna of this state." (Orn. of Illinois, 1889, 



P- 59-) 



The occurrence of this form in Illinois is most unexpected as it is 



far out of its usual range. 



362. Hylocichla ustulata swainsonii (Cab.). 

 Olive-backed Thrush. 



Turdus ustulatus swainsonii (Cab.), A. O. U. Check List, 1895, 

 p. 318. 



Distr.: North America in general, except Pacific coast of United 

 States, breeding from the northern border of the United States north- 

 ward to Hudson Bay and Alaska; south in winter to Mexico, Cen- 

 tral America, and northern South America. 



Adult: Upper parts, uniform olive, showing little or no difference 

 in color of back and tail ; eye ring and lores, tawny buff; throat and 

 breast with decided tinge of pale tawny buff, marked on breast and 

 sides of throat with dusky arrow-shaped spots ; sides of body washed 

 with grayish olive; belly and under tail coverts, white; a few obscure 

 grayish olive spots on the upper belly. Sexes similar. 



Length, about 7.15; wing, 3.90; tail, 2.75; bill, .50. 



The Olive-backed Thrush is abundant during the migrations in 

 spring and fall in Illinois and Wisconsin. Mr. Nelson records a speci- 

 men taken in June and another, July 9th, in the vicinity of Chicago 



