350 FRANCIS H. HERRICK 



After the second day of incubation a habit of sitting with the 

 head turned in a definite cUrection was formed and maint ined 

 with scarcely any deviation for two weeks. This habit is evi- 

 dently determined by the method of entering the nest, and the 

 bird faces the direction of easiest approach, where vision is 

 least interrupted. 



According to Howe ^^ the time occupied by the building robin 

 varies from 3 to 15 days, according to need and other con- 

 ditions, with an average of six da^^s in the elerven nests observed. 

 We shall not refer to his brief description of the process of con- 

 structing the nest for we consider it faulty at nearly every 

 point. 



Nest- Building in the Red Eyed Vireo. — We have frequently 

 referred to the exquisite pendent nests of the red-eyed vireo 

 (Vireo olivaceus), which are ahvays suspended between the 

 forks of a slender twig (see Part I, fig. q), and we have seen that 

 however diverse the materials employed, the form and dimen- 

 sions of the cup are remarkably constant (see Part II, p. 268). 



The nest of one of these vireos,'" the building of which was 

 watched from the vantage point of a window has also been 

 described (see Part II, nest No. 3, table III, p. 269); it was 

 begun at the fork of a maple twig, about 10 feet from a dwelhng 

 house, and 20 feet from the ground; when first noticed on May 

 30, at 1.30 p. M., it consisted of a minute mass of gray bast 

 and spiders' silk bound to the angle of the crotch. 



Tn building the statant nest, as in the case of the robin, the 

 materials, of whatever sort, are simply brought and laid upon 

 the site, where under the control of the bill they are subjected 

 to the molding and turning movements, which begin promptly 

 and cease only with the last finishing touch. Pendent nests 

 characteristic of vireos and orioles could never be built after 

 this method. With all such the work necessarily begins with 

 securing the first fibres to those chosen twigs destined to support 

 the nest. These fibres, moreover, represent the margin and 

 side of the future nest close to the angle of the fork. A loose 

 free-hanging mass is first formed, and this is gradually extended 

 on either side downward and outward from the crotch. (Com- 



39 Op. cit. p. 1G4. 



■'"For the opi)ortunity of studying this nest I am indebted to the kindness of Mrs 

 Robert E. Ruedy, Cleveland Heights, Ohio. 



