NESTS AND NEST-BUILDING IN BIRDS 343 



defines, commonly a foot or more from the nest. Drawing up 

 to attention, she pauses a moment as at leaving, holding high 

 her straw or ball of mud ; then if reassured she trips nimbly 

 to the site, drops her load and goes to work. 



At this nest the hen, when gathering material, and presumably 

 while feeding, as well as when at work, was under the constant 

 surveillance of the cock, and as suggested earlier (see part I, 

 p. 1 80), she is stimulated to her task by the degree of ardor 

 which he displays. The frequent singing of the male, while 

 his mate labors in the field or at her nest is a clear signal that 

 all goes well. As we shall later see, the male robin may take 

 a hand in nest-building, or possibly even bring food to the nest 

 (see p. 346), but his function is in the main complementary to 

 that of the female, and his chief role that of guardian and 

 incentor to action. 



Wet weather, unless too prolonged or too violent (see Part I, 

 p. 261), is no bar to the building robins, but tiie time of building 

 is not a matter of choice and is independent of the weather. 

 The mud which they employ to such good purpose, is taken 

 direct from the ground where of the right consistency. The 

 mud is brought in the mouth and is necessarily mixed with a 

 certain amount of saliva, though usually in the form of a ball 

 held in the bill ; these balls must be worked over to some extent 

 at the point where they are taken from the ground, and are 

 sometimes as large as a walnut. I have seen the holes left in 

 the soft mud from which balls have been removed, but have 

 never been able to watch the w^orking process, if there be any, 

 by which they are extracted and removed. 



While watching this robin, I once saw her leave the nest as 

 if the work of the visit were over, and step out on the branch, 

 when in a moment she wheeled about, returned and continued 

 to mold as before. At other times I have often seen a bird pick 

 up in this way stray materials and return them to the nest. Again 

 this bird, the molding process over, would hop to the branch, 

 uplift and stretch both wings together, until they nearly touched 

 over the back; when working with mud, the builder, will fly 

 into a tree and rub its bill clean on a branch before setting out 

 for a fresh load. 



Operations at this site ceased at 6.16 p. m. on the first day, 

 shortly after sun down. Although the work had lasted for nearly 



