298 BULLETIN 17 6, UNITED STATES NATIONAL MUSEUM 



caught her, but she did not object, for when she flew out of the door 

 she was soon back through the top of the stack with more food." 



Eggs. — Vaux's swift lays three to six eggs ; four, five, and six seem 

 to be the commonest numbers. The eggs are usually elliptical-ovate 

 or elongate-ovate, rarely ovate. They are pure dead white, without 

 gloss, or sometimes faintly creamy white in color. The measurements 

 of 51 eggs average 18.5 by 12.4 millimeters; the eggs showing the four 

 extremes measure 19.8 by 12.2, 18.5 by 13.5, 16.8 by 12.0, and 18.8 by 

 11.8 millimeters. 



Y(nmg. — Mr. Finley (1924) watched the feeding of the young 

 swifts in the nest described above, of which he writes : 



I stood outside at twelve o'clock, noon, and saw one of the parent Swifts 

 come flitting along just above the chimney top, suddenly swerve and drop in. 

 He, or she, whichever it was, was feeding every fifteen or twenty minutes. 

 I went below and with the aid of an electric light, I could see the bird feed 

 her young. Sometimes she would light on one side of the nest and sometimes 

 on the other, to feed. Once I saw her clutch the edge of the nest and brace 

 herself with her tail underneath, and she jabbed her bill in the mouth of a 

 young bird and fed by regurgitation. As she started up the long climb, she 

 quivered her mngs, hooked her sharp toes in the sooty side of the stack and 

 walked right up as if she were going up a ladder. 



William B. Davis (1937) made some observations on a nest located 

 in a brick chimney, and about 12 inches below the roof of the build- 

 ing, in Bellingham, Wash. ; on August 2, between 9 : 37 and 11 : 15 

 a. m., the parent, or parents, made eight trips to the nest to feed the 

 young. He writes : 



When I first looked into the chimney, I was greeted by the clamor of the 

 young. Their calls consisted of series of rasping notes uttered in rapid succes- 

 sion. The young were i)erched on the edge of the nest, each with its posterior 

 end projecting over the edge and with its head directed toward the corner of 

 the chimney. Below the nest the chimney was streaked with excrement, a cir- 

 cumstance which indicated the young were not defecating in the nest. This 

 probably explains the clean condition in which Edson found the empty nest when 

 it was collected two days later. No evidence was obtained that the parent bird 

 removed the fecal sacks of the young, although one can infer that it probably 

 did when the young were smaller and unable to perch on the edge of the nest. 

 Each time the parent returned from a trip afield, the young became vociferous, 

 their calls lasting until the old bird left. By listening for the calls of the young, 

 one could mark the coming and going of the adult. 



After the parent had returned from its sixth trip, I moved close to the chimney 

 and witnessed the feeding of the young. When first observed, the old bird was 

 clinging to the chimney beside the nest, supported partly by the stiff tail 

 feathers. The young were facing her (?), each with its mouth wide open 

 clamoring for food and vying with its nest mates. I was led to wonder what 

 relation existed between lustiness of voice and the chance of being fed at that 

 particular visit. Later, after additional observations, I learned that proximity 

 to the parent determined to a large extent which of the young was fed. At suc- 

 ceeding visits, the old bird alighted first at one side of the nest and then at the 

 other, feeding the one, or ones, closest. The food, consisting of insects, largely 



