Craig, Expressions of Emotion in Pigeons. 75 



Even when it is necessary to sound the ahirm-note while on the nest, 

 the bird subdues its voice into something very like a whisper. The 

 quietness of the brooding- time is thus a forced quiet, an active silence, 

 caused by inhibition. In fact, in the tame ring-dove, which has so 

 far lost its fear as to be at ease even during brooding, the inhibition 

 is largely removed, and the birds are far more noisy during incuba- 

 tion than are any of the wild species. Strong attachment of the 

 mates to one another is shown throughout the brood cycle by tame 

 and wild species alike. The notion that the comparative quietness 

 of the birds during brooding is due to lack of conjugal feeling, is a 

 mistake. 



Quietness and retirement fonn only one phase of a great alteration 

 of disposition during brooding; another phase is a sudden defensive 

 bravery and irascibility. The sitting bird, whether male or female, 

 defends the nest as valiantly as a brooding hen. And even when 

 off duty from incubation each bird is now moTe bold than ever in 

 attacking and driving away enemies. 



The eggs hatch in 14 days ; that is to say, on the 14th day after 

 the laying of the second egg. The hatching of the eggs, the arrival 

 of the young, gives again a stimulus of the same sort with the first 

 appearance of tlie eggs, and makes the parents again still more quiet, 

 more jealous, and more devoted to their parental duties. It has 

 already been shown (page 73) that the movement of the young under 

 the breast of the parent is a stimulus to the latter. Professor Whit- 

 man has found that when he needed a foster-parent for some valuable 

 young pigeon, he could take a ring-dove whose eggs were not yet 

 ready to hatch, and, by stroking her breast gently with his fingers 

 in imitation of the movements of the young, he could induce her to 

 connnence feeding. Thus we see that the feeling of the movements 

 of the young is a stimulus not only to the feeding impulse but at the 

 same time to the secretion of "pigeon's milk" in the crop. That 

 the young are a greater attraction than are the eggs to the sitting 

 bird, is evidenced by. the frequency with which the parents sit both 

 together on the little birds, often crowding each other to get a larger 

 share of the coveted nestlings. That the hatching-out of the young 

 gives an additional stimulus to maternal jealousy, is shown by the 



