BIRDS. 23 



19. PANYPTILA MELANOLEUCA, Baird, (p. 141.) White-throated Swift. 



PLATE XVIII, FIG. I. 



6017. Camp 123. Bill Williams Fork, New Mexico, February 16, 1854. (169.) Ken 

 nerly and Mollhausen. 



First described from the specimen collected by the expedition. 



This curious and interesting bird was found in the month of February among the canons of 

 Bill Williams Fork. We did not observe it elsewhere during our journey. Large flocks at 

 any time could be seen in the vicinity of these canons, flying and circling around very high, 

 and far beyond the reach of shot. Towards the close of the day, when the sun had sunk 

 behind the hills, they occasionally descended lower. We found them only where the walls of 

 the canons were very high and consisted of almost perpendicular masses of rocks. Sometimes 

 we have seen them sweeping down and then ascending nearly perpendicularly very near the 

 stones, as if examining them in order to select a place for their nests. The construction of 

 these had obviously not yet commenced, as we saw none engaged in the work, nor did we 

 observe any old nests, unless these birds build like the common cliff swallow, (Hirundo fulva,} 

 of which there were many also in this region, and whose nests were found in many places. 

 Mr. Mollhausen, however, is inclined to the opinion that they build in the holes and crevices of 

 the cliffs. In its flight and habits, as far as we were able to observe, it closely resembles the 

 common chimney swift, (Chaetura pelasgia.) 



20. ANTROSTOMUS NUTTALLII, Gas sin, (p. 141.) Nuttall s Whipporwill. 



6004. Camp 130, New Mexico, February 23, 1854. (177.) Kennerly and Mollhausen. 



The only specimen of this bird that we saw was presented to us on the Great Colorado river 

 by a Mexican boy, who had captured it alive by some means. 



21. MILVULUS FOEFICATUS, Swainson, (p. 169.) Scissor-tail. 

 7381. San Antonio, Texas, July, 1853. (15.) Dr. Kennerly. 



We frequently saw this beautiful and singular fly-catcher as we marched from the Gulf of 

 Mexico several hundred miles into western Texas, but beyond this limit we saw them no more. 

 We found them among the thick mezquite (Algarobia) bushes, as well as upon the open 

 prairie. When perched they were generally on the summit of a bush or tall weed, the tail 

 being constantly in motion. Frequently they would dart off after some passing insect, circling 

 around, showing occasionally the singular bifurcation of the tail, but seldom alighting again 

 on the same bush, as many other fly-catchers do. We have sometimes seen it upon -the open 

 prairie fly for a long distance near the earth, as if in search of its insect prey. 



22. SAYORNIS NIGRICANS, Bonap, (p. 183.) Black Fly-catcher. 

 7215. Camp 105, Pueblo creek, New Mexico, March 19, 1854. (189.) K. & M. 



After passing the mountains of California and descending into the valley of the Sati Gabriel 

 river, we found this little bird quite abundant, though we had not noticed it before. It was 

 generally found perched upon the summit of a bush, from which it would occasionally make 

 short excursions in search of its prey. At this season, March, they were rarely found in pairs, 

 so I presumed that they were hatching. 



