226 BIRDS OF THE PLAINS 



structure. At first the birds are afraid of the conceal- 

 ing object, but soon maternal affection overcomes their 

 fear. 



Mr. Herrick's method of overcoming the second of 

 these two difficulties is to remove the nest to be photo- 

 graphed from the concealed situation in which it is 

 usually built, and place it in a more open place. If the 

 nest be thus moved when the young are some seven or 

 eight days old, the parents will almost invariably con- 

 tinue to feed their young in the new situation, for at that 

 particular period the parental instinct is at its zenith. 

 In addition to obtaining a splendid series of photo- 

 graphs, Mr. Herrick has observed, from a distance of a 

 few inches, the nesting habits of several American 

 birds. As the result of these observations he is able 

 to declare that nest-cleaning follows each feeding with 

 clock-like regularity. " The excreta of the young," he 

 writes, " leave the cloaca in the form of white opaque 

 or transparent mucous sacs. The sac is probably 

 secreted at the lower end of the alimentary canal, and 

 is sufficiently consistent to admit of being picked up 

 without soiling bill or fingers. The parent birds often 

 leave the nest hurriedly bearing one of these small white 

 packages in bill, an action full of significance to every 

 member of the family. . . . Removing the excreta 

 piecemeal and dropping it at a safe distance is the 

 common instinctive method, not only of insuring the 

 sanitary condition of the nest itself, but, what is even 

 more important, of keeping the grass and leaves below 

 free from any sign which might betray them to an 

 enemy." These packets of excrement are quite odour- 



