298 LIFE HISTORIES OF NORTH AMERICAN BIRDS. 



foot high, covered with spagnum moss, Co2]tis trifoUa, Oxalis acetosella, and there 

 were also a few other small plants growing fron^ it. A single stem of a small 

 bush protruded from the top of the opening. The hollow in which the nest was 

 placed was lined with fine, diy grass and black, hair-like rootlets, 



I think only one brood is raised in a season, as a most careful search 

 failed to reveal a second nest in the vicinity. The birds were not seen afterwards, 

 althongh the locality was visited several times. The return migration com- 

 mences usually in the latter part of August, and none winter in the United 

 States. Four eggs are ordinarily laid to a set; very rarely five. Their shape 

 is usually ovate; the shell is close grained, rather frail, and without luster. The 

 ground color is dull white, and the fine markings, which are usually mimite 

 and generally heaviest about the larger end of the egg, vary from cinnamon 

 rufous to walnut brown; occasionally a specimen shows a speck or two of 

 heliotrope purple. 



The average measurement of sixteen eggs in the United States National 

 Museum collection is 16.94 by 12.91 millimetres, or about 0.67 by 0.51 inch. 

 The largest egg measures 17.53 by 13.21 millimetres, or 0.69 by 0.52 inch; the 

 smallest, 16.26 by 12.70 millimetres, or 0.64 by 0.50 inch. 



The type specimen. No. 25597 (PI. 2, Fig. 23), Ralph collection, from a set 

 of four eggs, was taken by Dr. William L. Ralph, June 17, 1892, near Wilmurt, 

 Herkimer County, New York, and represents aliout an average-marked egg of 

 this species. 



no. Empidonax difificilis Baird. 



WESTERN FLYCATCHER. 



Empidonax difficilis Bated, Birds of North America, 1858, 198 (in text). 



(B 114«; C 2.59, part; R 32.3; C 389; U 404.) 



Geographical range: Western North America; east to the eastern foothills of the 

 Rocky Mountains and adjacent ranges; north to southern Alaska; south to Lower Cali- 

 fornia, and in winter through western Mexico to Costa Rica, Central America. 



The breeding range of the Western Flycatcher, also known as the "West- 

 em Yellow-bellied" and "Baird's" Flycatcher, extends through western North 

 America from Hot Spring Bay in southern Alaska (where Dr. T. H. Bean took 

 a specimen on June 5, 1880, and informs me that it is not at all uncommon), 

 through British Columbia and the Pacific Coast States, south to northern Lower 

 California, Arizona, New Mexico, and probably western Texas, and in the inte- 

 rior, through Utah, Nevada, Idaho, western Montana, Wyoming, and Colorado. 



Judging from the various records, the Western Flycatcher seems to be 

 much more common in the coast districts west of the Sierra Nevada and Cascade 

 ranges than in the interior, but it is also fairly common in Colorado, Arizona, 

 and portions of New Mexico. Mr. R. S. WiUiams found it breeding in Belt 

 Canyon, IMontana, and kindly sent to the United States National Museum col- 

 lection both skins and eggs from that locality. 



