ISbT.J PKOCEEDINGS OF UNITED STATES NATIONAL MUSEUM 201 



The species is kuowu to be a simmier resident of the couutry to the 

 eastward of the Sierras, aud if found at all to the west of the mountains, 

 in the northern part of California, it is as a rare visitor, for there is no 

 record of any suchdistributiou, and 1 did not meet with it except upon 

 this occasion. It was collected at Yreka by ]\Ir. Vieille. 



Chordeiles virginiauus henryi (Cass.)- Wcsiern Nighthaick. 

 X common summer inhabitant of the open country. 



Family MICROPODID.E. Swifts. 



Chsetura vauxii (Towns.). I'aux's Swift. 



"Common in California." (Newberry.) 



Family TROCHILID.E. IIcmmixgiukds. 

 Trochilus alexandri Bonrc. & Muls. Bluclc-chinntd Hummin'jhird. 



A very common summer resident of the foothills, breeding- numer- 

 ously on the Lower McCloud Kiver, where seven nests were found at 

 intervals from May 2S to June 20, 1883. These nests were without 

 exception built on the branches of alders and other low bushes close 

 by the McCloud liiver or the creeks Howing into it, none of them being- 

 loo liigli to be easily reached from the ground. 



While composed mainly of the cottony down of plants general!^ used 

 by Hummingbirds for building material, they were very differently 

 disguised by the materials used for their outside covering. Instea<l of 

 being lichen-coated, in the manner of nests found in large trees, these 

 were closely covered with the brown husks of buds and (;ertaiu sniall 

 seeds, which were finally enveloped in a network of s[)ider-web to hold 

 them in place. One nest, taken June, 21, was so heavily covered with 

 thi-5 netting of spider's manufacture as to be remarkably finn aud hard 

 for a Humming-bird's nest. Another, taken May 28, was composed of 

 the above-mentioned seed husks and spider-webs to the total exclusion 

 of the usual down of willows and other plants. Only one nest in the 

 lot was entirely lichen-coated, aud as it was built in a young live oak 

 this coating corresponded with the gray-colored branch on which it rested 

 much better than would the brownish color emi^loyed to disguise the 

 nests in the lichen-colored branches of the alders. 



Here we have a beautiful adaptation of means to reciuisite ends, which 

 may be further illustrated by similar methods of concealment adopted 

 by two of the following species. In all these instances the artifices 

 resorted to by the birds to render their nests inconspicuous ap|)eared to 

 be efl&cient, for I do not remember even to have discovered any of the 

 twenty or more Hummingbirds' nests I have collected until their posi- 

 tions were disclosed by the movement of the builders or the actions of 

 the anxious parent birds. 



