88 EXPLORATIONS AND SURVEYS WEST OF 100TH MERIDIAN. 



CAPRIMULGLD^E (the Goatsuckers). 



72. Antrostomus nuttalli (Aud.) NuttalFs Whippoorwill. 



This bird is found in varying numbers throughout this entire region, 

 but everywhere it is much more numerous than its cousin of the Eastern 

 States. It makes its appearance in the deeply-shadowed portions of the 

 river bottoms a few minutes before dusk, and, as soon as night settles 

 down, the rather mournful note of poor-will, poor-will, may be heard 

 coming from the edges of the woods, and even from the sage-brush 

 plains. Their notes are most often noticed in early evening, and again 

 just before dawn, but not infrequently their song is heard through the 

 entire night. When on the wing after insects, their flight consists of 

 rapid, irregular turnings and windings, which are prolonged but a 

 moment or so, when they alight, often on a fallen log, but usually on the 

 bare ground. Occasionally, at dusk, I have seen them alight almost at 

 my feet, without betraying any sense of ray presence. When flying 

 they emit acoristantly^repeated clucking note, which is, I think, common 

 to both sexes. Their eggs are pure white, without spots, and are 

 deposited on the ground during the latter part of June. 



73. Chordeiles popetue (Yieill.), var. henry i, Oass. Western Night- Hawk. 

 An exceedingly abundant species everywhere in the vicinity of water. 



Often seen at noonday flying over the surface of stagnant pools, catch- 

 ing the insects which swarm in such places. They are, however, usually 

 most active just before dusk, and on the banks of the Eio Grande I 

 have seen them at this time make their appearance in hundreds. 



TROCHILID^ (the Humming-Birds). 

 71. Selasphorus platycercus (Sw.) Broad-tailed Humming-Bird. 



This, the only humming-bird seen in this region, was found in very 

 great numbers. Though most common on the creeks, at an altitude of 

 about 7,000 feet, it also reaches well up timber-line. A nest, found 

 June 14, was saddled to a horizontal limb of a small spruce ; a second, 

 taken the IvJth, w 7 as built on a small, swinging branch of a cottonwood. 

 They are less artistic structures than usual with birds of this family, 

 and are composed of cottony substances from plants, covered externally 

 with bits of bark and moss. Both contained two white eggs, perfectly 

 fresh. During the mating, and perhaps also through the entire breeding 

 season, the flight of the male is always accompanied by a curious, loud, 

 metallic, rattling noise, which he is enabled to produce in some way by 

 means of the attenuation of the outer primaries. This is, I think, 

 intentionally made, and is analogous to the love-notes of other birds. 

 Though 1 saw many of these birds in the fall, it was only very rarely 

 that this whistling noise was heard, and then with greatly diminished 

 force. 



