NESTS AND NEST-BUILDING IN BIRDS 349 



depended somewhat upon the pitch or quahty of the sound, 

 for a similar alarm from another pair of robins elicited a loud 

 and emphatic tseet, although she did not desist a moment from 

 her labors. While watching these birds I sat at a distance 

 of about ten feet with a rain cloak drawn over me. As in 

 the former case noticed, so long as there was no movement 

 all went well, but if an arm was inadvertently moved, the worker 

 would stop at once, squeal out her alarms, and dart hurriedly 

 away; yet, as before, in a moment she would return with a 

 fresh load of mud or straw. As at a former nest described 

 there was a long lull in the building operations at about noon, 

 varying from one-half hour to an hour. 



On the morning of the fourth day this nest appeared perfect, 

 and thereafter for tw^o days, visits to it either for the purpose 

 of adding fresh materials or for sitting must have been very 

 infrequent. In short it appeared to have been deserted. It 

 was begun in the afternoon of June 24, and at noon on June 

 28 the female slipped off c[uietly after laying her first egg. On 

 the next day, June 29, she was seen at nine o'clock sitting 

 quietly in a neighboring tree, waiting evidently for an oppor- 

 tunity to enter her nest unobserved; at 10.48 a. m. she was on 

 the nest and upon leaving at 12.06 p. m., one hour and eighteen 

 minutes later, the second egg had been deposited. Leaving 

 her nest voluntarily at this time she was seen to go to the garden 

 for food. Six minutes later she was at the nest again, and there 

 remained with only brief forays for food, lasting from three 

 to four minutes ; incubation had regularly begun. The third 

 egg which formed the complement, was laid between the hours 

 of 10 and 11.30 A. M. on June 30. 



In the robin, incubation lasts from 13 to 14 days, and is per- 

 formed wholly or almost wholly by the hen, and during this 

 period no building material is ever added to the nest, so far 

 as observed. I have seen this bird leave her nest for food in early 

 morning, towards noon, as well as in late afternoon, but only 

 for intervals varying from a few seconds to a few^ minutes. 

 Once at 5.30 p. m. during a pouring rain storm the drenched 

 sitter was seen to leave abruptly and fly four hundred feet to 

 a garden where she was met by the male. No food was seen 

 to pass between them, and she returned after an absence of 

 2 1 minutes. 



