424 BULLETIN 17 6, UNITED STATES NATIONAL MUSEUM 



portions of the aspen groves there are numerous dead, black or gray 

 mistletoe knots, about the size of hummingbirds' nests, and the birds 

 seeta to realize the value of the protection thus offered ; most of the 

 nests that he found there were built either upon one of these knots 

 or in such a position that the nest would look exactly like one of them ; 

 and he had diiRculty in recognizing a nest until he could see a bird 

 alight upon it. 



Nine nests that Dr. Joseph Grinnell (1908) recorded in the San 

 Bernardino Mountains of southern California "varied in height above 

 the ground from twenty-two inches (measured) to seventy feet (esti- 

 mated) ; I should judge the average height to have been about thirty- 

 five feet, as the majority were above that height. The nests were all 

 in caHons, though none were directly over or very near the water, 

 as with some other species of hummingbirds. One was located in an 

 alder, two in silver firs, and six in yellow and Jeffrey pines." 



The first nest mentioned above, as 22 inches above the ground, is in 

 the Thayer collection in Cambridge ; it was near the end of a droop- 

 ing bough of a young silver fir growing on a canyon side and only 

 15 inches from the face of a huge overhanging boulder; its general 

 appearance is dark gray, being made of various gray and brown 

 fibers, bark scales, and bits of inner bark ; the bottom of the cavity 

 only is lined with grayish-white down; it measures II/2 by 1% inches 

 in outside diameter and V/g inches by seven-eighths of an inch in 

 inner diameter; it is only seven-eighths of an inch high outside and 

 five-eighths of an inch deep inside. 



Mr. Weydemeyer (1927) says of its nesting habits in northwestern 

 Montana : 



The nest of this Hnminingbird is placed in a coniferous tree. Within this 

 limit, the choice of an individual tree appears to depend more upon the 

 location than upon the species. In the higher elevations of Lincoln County, 

 nests are placed in alpine firs. Along the streams of the Transition zone, the 

 trees most commonly used are the Engelmann spruce, western hemlock, and 

 arborvitae. I have found one nest in a Douglas fir, but have seen none in 

 pines. Near Libby I have observed nests in three species of trees within a 

 few yards of each other along a stream. Evidently, to suit the requirements 

 of the birds, the tree must be a conifer standing on the bank of a creek, or 

 beside a road or other opening in the forest, with one of its lowermost branches 

 swinging free from all other foliage and commanding a clear view in prac- 

 tically all directions. 



The word "lowermost" is used with a purpose. All the nests of this species 

 that I have seen have been placed on the lowermost living branch on its side 

 of the tree. This habit determines the height of the nest above the ground 

 or water. In the region considered here the distance generally ranges from 

 four to ten feet. * * * 



But little variation occurs in the general types of materials used in con- 

 structing the nests. In comparative bulk the average nest is composed ap- 

 proximately as follows: plant down, 60 per cent; tree lichens, 20 per cent; 



