58 BEHAVIOR OF PIGEONS. 



When one bird leaves, this departure is the signal for the other bird to take the 

 nest, and as a rule this is done immediately. Sometimes one bird refuses to go 

 to the nest when the mate leaves it, and the latter is then forced to return; other- 

 wise the eggs are left uncovered until the first bird awakens to its responsibility. 

 These periods in which the eggs are left uncovered vary from 1 to 6 minutes and 

 they usually occur in the early part of the incubation period. The female was 

 responsible for this lack of care in the majority of cases. While on the nest either 

 bird may give the nest-call as a call for relief, and this call is sometimes heeded 

 and sometimes not. 



When one bird takes the initiative, either in leaving or taking the nest, this 

 act serves as a stimulus to its mate. Under the caption "Incubation left to young," 

 an instance is given in which a young bird goes to the nest, and this serves as the 

 stimulus for the old bird to resign. During the early stages of an incubation period 

 a pair of doves may be still feeding the young of the former cycle. The title of 

 this note might indicate that the young bird's action in going to the nest is to be 

 interpreted as an attempt to participate in the incubation. Such an interpreta- 

 tion is hardly necessary. 1 The note contains a seeming discrepancy of statement. 



A pair of wood-pigeons have young able to fly and feed, but they are still fed by the 

 parents. One young is in the nest-box and both old birds are on the perch [? a mis-state- 

 ment. EDITOR]. The young goes into the nest to sit beside the old bird, and the old 

 bird resigns as she would for her mate. I drove the young off the nest and the old bird 

 went back to duty. I have seen this behavior in the case of ring-doves and in some 

 other species. (R 18.) 



DEFECTIVE ALTERNATION. 



A Japanese turtle female, mated to a homer, deserted her eggs 5 days after the first 

 egg was laid. I had already transferred them to another pair and put other eggs in their 

 place. The male homer has continued up to the present (for 5 days) faithful to his own 

 duty, incubating during the day, and has tried to fulfil the duty of his mate besides. He 

 has sat every night so far, while she has done nothing since her desertion. It is really 

 remarkable that a male dove should undertake double duty. This is not the normal course 

 of incubation, and one would hot expect pure instinct to provide in one sex against the 

 abnormal in the other. When instinct once ceases to acknowledge eggs, nothing can 

 induce the bird to pay them any attention. Why is it that a faithful bird, accustomed to 

 only regular hours of day, feels impelled to take the nest even at night when its mate 

 deserts it? Is the sitting instinct continuous, and is the usual exchange regulated only 

 by a regular round of needs? That is, does the female leave her eggs in the morning 

 because her mate comes to relieve her, and would his leaving the nest call her back to it? 

 This is certainly true in many cases. The male continues to sit at nights as well as during 

 the day for 4 more days, at which time the female laid again in another nest. (BB 5.) 



A male will often sit on the eggs at night in case the female deserts or dies; he will also 

 sit overnight on the young as well as on eggs. An example of the latter behavior has just 

 occurred where a male ring-dove is sitting at night on young only a few days old. (R 7.) 



In the bronze-wing record the editor finds several cases of defective behavior 

 on the part of the male. He fails to cover or feed the young during the day. He 



1 A case, however, is elsewhere (Chapter IX) reported by Dr. Riddle, in which a young bird 38 days old nested 

 eggs, and engaged in sexual billing with its two male foster-parents. EDITOR. 



