488 LIFE HISTOBIES OF NORTH AMERICAN BIRDS. 



similar. As many sections where Bullock's Oriole breeds are still rather 

 sparsely settled, less twine and such other material as may be picked up about 

 human habitations enter into its composition. Shreds of wild flax and other 

 fiber-bearing plants and the inner bark of the juniper and willow are more 

 extensively utilized; these with horsehair and the down of plants, wool, and 

 fine moss, furnish the inner lining of the nests. According to my observations, 

 the birch, alder, cottonwood, eucalyptus, willow, sycamore, oak, pine, and juni- 

 per furnish the favorite nesting sites; and in southern Arizona and western 

 Texas it builds frequently in bunches of mistletoe growing on cottonwood and 

 mesquite trees. 



The nests are usually placed in low situations, from 6 to 15 feet from the 

 ground, but occasionally one is found fully 50 feet up. A very handsome nest, 

 now before me, taken by Dr. Edgar A. Mearns, United States Army, near Fort 

 Hancock, Texas, on June 30, 1893, just after the young had left it, is placed 

 among six twigs of mistletoe, several of these being incorporated in the sides of 

 the nest, which is woven entirely of horsehair and white cotton thread, making 

 a very pretty combination. The bottom of the nest is lined with wool. Out- 

 wardly it is 6 inches deep; inside, 4£ inches. The entrance, at the top, is oval 

 in shape, somewhat contracted, and 4 by 2£ inches wide. Another peculiar 

 specimen before me, taken near Yreka, California, May 29, 1860, is woven 

 among and fastened to a bunch of needles of the long-leafed pine; this nest 

 resembles an inverted cone, and is quite unique in structure. I have also seen 

 double nests, one placed beside and fastened to one previously built that had 

 for some unknown reason been abandoned. 



The number of eggs to a set varies from three to six; sets of five and four 

 are perhaps most common, while those of six are not very rare. Bullock's 

 Oriole is occasionally imposed upon by the Dwarf Cowbird in Arizona, and by 

 this as well as the Red-eyed Cowbird in southern Texas. Only one brood is 

 raised in a season, and the duties of incubation, which are performed almost 

 exclusively by the female, last about fourteen days. I have often watched the 

 sitting bird, and have never seen the male on the nest. At Camp Harney a 

 number bred at the Post, within a few yards of the houses, and when not 

 molested they soon became as familiar as the Baltimore Oriole. The sexes are 

 extremely devoted to each other, and valiantly defend their eggs and young. 

 I once saw a pair vigorously attack a Richardson's squirrel (Sciuras richardsoni), 

 which evidently was intent on mischief, and drive it out of the tree in which 

 they had their nest. Both birds acted with the greatest courage and dashed at it 

 repeatedly with fury, the squirrel beating a hasty retreat from the combined 

 attack. The young are large enough to leave the nest in about two weeks, and 

 are diligently guarded and cared for by both parents until able to provide for 

 themselves. The return migration in the more northern portions of their range 

 to their winter homes in Mexico begins usually in the first half of August, and 

 by the end of this month nearly all have departed. 



The eggs are mostly elongate ovate in shape, a few are ovate, and an occa- 

 sional set is almost wedge-shaped or cuneiform. The shell is close grained and 



