268 FRANCIS H. HERRICK 



Further, in an orchard on the opposite side of the house, but 

 less than five rods from this point, another waxwing built a 

 grass nest and used as lining the fluffy heads of the low cud- 

 weed, patches of which were growing on the hillside close at 

 hand. Without splitting words on the subject of " choice " 

 in such selections, it is evident that a great variety of natural 

 products awaken certain responses concerned with the complex 

 acts exhibited in building the nest, and awaken them promptly 

 in all such birds. 



We have already spoken of the general methods of arranging 

 the materials used in building (No. 3 of the analysis given above), 

 and are now ready to consider the most constant characters of 

 nests (Nos. i and 2), the form and dimensions of the inner wall, 

 and the treatment of the outer surface when characteristic. 

 To repeat, we find the characters of the inner gup, and of the 

 outer surface when subjected to peculiar methods of molding, 

 smoothing, or incrustation, the most constant characters of 

 increment nests, because due to instinctive activities of uniform 

 type. The amount and nature of the substances employed are 

 as a rule quite subordinate to the methods of work. When 

 the outer wall does not undergo a peculiar smoothing or garnish- 

 ing process the nature of this surface is subject to greater varia- 

 tion and is consequently unimportant. 



5. VARIATIONS IN THE NESTS OF CERTAIN BIRDS 



The uniformity and variations in the characters of nests 

 already enumerated and described will be further illustrated 

 by specimens of the work of red eyed vireos {Vireo olivaceous), 

 wood pewees {C onto pus virens), and the hummingbirds. These 

 particular nests may be regarded as typical examples, but to 

 give numerical results of any worth large numbers of specimens, 

 drawn from every part of the known range of the several species 

 would have to be examined. 



Variation in nests of the red eyed vireo. We have seen that 

 nests of the pendent type are much less variable in regard to 

 the characters given above than in most of those built upon a 

 basal support, and they are seldom found close to the ground. 

 The supports chosen for such hanging nests are of necessity 

 more uniform, and the nests themselves present a corresponding 

 similarity in their measurements, as well as in the kinds and 



