FLYCATCHERS 257 



1'. Length 5.90-6.75. 



2. Wings and tail shorter. Western Nebraska to Atlantic. 



virens, p. 258. 

 2'. Wings and tail longer. Plains to Pacific . . richai dsonii, p. 258. 



Subgenus Nuttallornis. 

 459. Contopus borealis (Swains.). OLIVE-SIDED FLYCATCHER. 



Adults. Under parts with whitish median tract between dark, somewhat 

 streaked lateral parts, white sometimes 

 faintly tinged with yellow ; upper parts 

 sooty, conspicuous tuft of white cottony 

 feathers on sides of rump (usually con- 

 cealed by wings). Young: similar, but Fig. 

 wing coverts tipped with buff y, or brown- 

 ish instead of white. Length: 7.10-7.90; wing 3.90-4.50, tail 2.80-3.50, 

 exposed culmen .58-.70, tarsus .55-.60. 



Remarks. This is the only Contopus that has white cottony tufts on the 

 sides of the rump, or first quill longer than fourth. 



Distribution. Breeds in Canadian zone forests of North America from 

 Hudson Bay south through the higher parts of the United States ; migrates 

 to Peru, Central America, Columbia, and northern Peru. 



Nest. Small, of wiry materials fastened skillfully to branches of conif- 

 erous trees, 40 to 60 feet from the ground. Eggs : usually 3, creamy, gen- 

 erally wreathed with spots of brown and lavender. 



Food. Winged insects, such as beetles, butterflies, moths, gadflies, and 

 grasshoppers. 



In the high Sierra as in the Canadian forests throughout the United 

 States the pu-pip' of the olive-sided calls your attention to a solitary 

 bird with a dark gray breast and white median line, perched on the 

 tip of an evergreen spire. Its body is quiet, but its head is turning 

 from side to side, and suddenly it launches into the air, catches an 

 insect, turns, and with wings and tail spread sails back to its perch. 



It calls a great deal in the twilight, and in the fir belt of Mt. 

 Shasta, where its voice is one of the commonest forest sounds, as the 

 evening shadows gathered over the noble trees under which we were 

 camped, the mellow pu-pip', pu-pu-pio' , pu-pip', pu-pu-pio', came 

 down to us in soothing cadence till the camp-fire shone in the dark- 

 ness. 



Subgenus Contopus. 



460. Contopus pertinax pallidiventris Chapm. COUES FLY- 

 CATCHER. 



Adults. Upper parts grayish brown, tinged with olive ; under parts nearly 

 uniform olive gray, chin slightly whitish, belly and under tail coverts dull 

 yellowish ; first quill much shorter than 

 fourth. Young : similar, but wing cov- 

 erts tipped with buffy or brownish. 

 Length : 7.70-8.00, wing 3.80-4.45, tail 

 3.60-3.90. Fig. 333. 



Remarks. The Coues flycatcher is 

 about the size of the olive-sided, but its under parts arc strikingly uniform 



