EASTERN YELLOW WARBLER 165 



ground in the fork of the sapling. During an hour of observation the female 

 continued to carry plant-down at intervals of about four minutes although once 

 it did not bring any material for twenty minutes. At noon the plant-down 

 mass had increased to about three inches in diameter and was more compactly 

 pushed into the fork. By 6 :45 p. m., there were many strands of plant fibers 

 and grasses woven around and through the plant-down in such a way as to 

 wrap and bind the plant-down around the small twigs of the fork. The nest 

 was just assuming a cup-shaped structure. The female was now bringing large 

 loads of a mixture of gi-asses and plant fibers and working at a rate of about one 

 trip every four minutes. The first day's building was completed at 7:55 p. m. 

 The nest was now partially surrounded with woven plant fibers and grasses 

 with a slight formation of a rim. 



On the second day the work continued and the "rim consisted of 

 plant fibers and grasses woven partly into the original down but 

 mostly into the sides and around the top. At 6:45 p. m., the nest 

 appeared completed with a well-formed cup, plant-fiber and grass rim, 

 and a plant-down floor." The third day was partly rainy and little 

 was accomplished but "by 8 : 00 on the fourth morning, the plant-down 

 inside the nest was smoothed out and contained a few strands of fine 

 grasses. * * * During all the observations on the building of 

 this nest the male at no time was seen to bring any nest material. 

 However, since there were many hours during the day when no obser- 

 vations were made, it is possible that he might have helped at some 

 time. * * * At 6 : 30 a. m., the following day, one egg was found 

 in the nest. * * * The dates of the beginning of construction and 

 the dates the first eggs were laid were obtained for two other nests, 

 and the time which elapsed in both cases was four days." 



Only the female was seen to take part in the building of the nest 

 that Mr. Smith (1943) watched, but my experience was somewhat 

 different. On May 10, 1942, 1 found a pair of yellow warblers build- 

 ing a nest in the top crotch of a blueberry bush, close to the side of 

 a country road. They were very tame and gave me an unusual oppor- 

 tunity to watch them for over an hour at short range. I parked my 

 car within 5 feet of the nest and took motion and still pictures, with 

 cameras even nearer. The nest was nearly done and they were putting 

 in the lining. Both birds helped in the work, but the female did nine- 

 tenths of it. She came at frequent but rather irregular intervals, 

 bringing a billful of soft plant down that looked like the down from 

 ferns, some of which I found growing nearby, and to which I saw her 

 making frequent trips; the fronds of the cinnamon ferns were just 

 unfolding. This material she deposited in the cup of the nest and 

 settled her body down into it, smoothing the lining into place by turn- 

 ing her body around in different directions, pressing it down with her 

 body and up against the sides of the cup with a sidewise motion of the 

 wings. Occasionally she reached over the rim of the nest, smoothing 

 it with her neck and tucking in the loose ends with her bill. The 



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