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



structure, usually placed near the end of a branch. The eggs are 

 three to four (usually three) in number, cream white, speckled or 

 spotted chiefly at the larger end with rusty brown, and measure about 

 .72 X .52 inches. 



The Field Museum collection contains the following sets of eggs 

 from northern Illinois: 3 eggs, Joliet, 111., June 6, 1906; 3 eggs, 

 Joliet, 111., June 8, 1906; 3 eggs, Joliet, 111., June 9, 1906; 3 eggs, 

 Joliet, 111., June 16, 1906; 3 eggs, Joliet, 111., June 24, 1907; 3 eggs. 

 Lake Forest, 111., June 27, 1906. 



Length, 5,50 to 6.10; wing, 2.70 to 2.85; tail, about 2.35 to 2.50; 

 bill, about .45. 



2 1 4. Empidonax traillii (Aud.) . 

 Traill's Flycatcher. 



Distr.: "Western North America, from the Mississippi Valley 

 (Ohio, Illinois, and Michigan) to the Pacific, and from the Fur 

 Countries south into Mexico." (A. O. U.) 



Adult: First primary, decidedly shorter than fifth; eye ring, and 

 wing bars (formed by the pale tips of the greater and lesser wing 

 coverts) , ashy white ; upper mandible, brownish black; under mandi- 

 ble, pale brown or horn color; upper plumage, olive brown, darker 

 on the head; throat, whitish; breast and sides of body, washed with 

 olive gray; belly, whitish, faintly tinged with pale yellow. 



Length, 5.50 to 6.10; wing, 2.70 to 2.85 ; tail, about 2.35 to 2.50; 

 bill, about .45. 



Traill's Flycatcher differs from the eastern race (£. t. alnorum) 

 in having the upper parts brownish olive (instead of greenish olive). 

 There are other slight characters which are apparently inconstant, 

 such as somewhat larger bill and browner wing bands. 



A regular, but by no means common summer resident in Illinois 

 and of casual occurrence in Wisconsin. Mr. F. M. Woodruff records 

 a brood of young birds observed near Calumet Lake, Chicago, June 10, 

 1896. Mr. Robert Ridgway found it breeding near Mt. Carmel, 

 111., and Mr. B. T. Gault procured a nest and four eggs in Dupage 

 Co., 111. Kumlien and Hollister state (Birds of Wisconsin, 1903, p. 

 83): "A specimen taken at Delavan (Wisconsin), August i, 1907, 

 has been identified by Mr. Brewster as typical traillii. Perhaps occurs 

 as a regular summer resident in parts of southern and southwestern 

 Wisconsin; but more specimens will be necessary to satisfactorily 

 determine its range and abundance." 



The nest is cup shaped and is usually built in forks of upright 

 branches of bushes or small trees. The eggs are from 3 to 4, cream 



