178 BULLETIN 195, UNITED STATES NATIONAL MUSEUM 



In addition to the materials named above, nests have been found to 

 contain green moss, dead leaves, cotton, hair, wool, and occasionally a 

 piece of cast-off snakeskin. 



On at least two occasions, a cowbird's egg has been found in the nest 

 of this wren, according to Dr. Herbert Friedmann ( 1929) . 



A. Dawes DuBois tells me of a nest he found that "was between two 

 sheets of loosely placed sheet iron in the flat roof of a farmer's shelter 

 for pigs; he has another in his collection that "was in a sack hung up 

 with seed corn in an old outhouse ; there was a hole in the side of the 

 sack and through this the wrens entered." And Aretas A. Saunders 

 writes to me that he saw one building a nest in a wood pile. 



Eggs. — The commonest numbers of eggs found in the nests of 

 Bewick's wren run from 5 to 7 ; perhaps 7 might be called the average ; 

 as few as 4 and as many as 11 have been found, and sets of 8 or 9 are 

 not very rare. The eggs are often very pretty ; the ground color is 

 white, and they are more or less irregularly spotted and dotted with 

 reddish brown, umber, various shades of lighter brown, purplish 

 brown, drab, or lavender. The markings are sometimes concentrated 

 in a ring about the larger end. Some are very finely and faintly sprin- 

 kled with minute dots ; and some are nearly immaculate. The measure- 

 ments of 40 eggs in the United States National Museum average 16.4 

 by 12.7 millimeters ; the eggs showing the four extremes measure 17.8 

 by 12.7, 16.8 by 13.2, 14.6 by 12.8, and 15.3 by 11.7 millimeters. 



Young. — The period of incubation has been estimated as 10 to 14 

 days, but most observers agree on 14 days as the average. Probably 

 only the female incubates, as suggested by one of the western races. 

 The young remain in the nest about 14 days and are fed by both 

 parents while in the nest and for 2 weeks or more after they leave it. 

 Two broods are generally raised in a season, and sometimes three in 

 the South. Butler (1898) says that the young return "every night 

 to roost in the nest after they are able to fly." 



M. B. Skaggs (1934) timed the feedings of a brood of four young 

 for four periods of one hour each on three different days, with the 

 following results : 



First day : Rain almost constantly. Fed 13 times at an average of 4.61 minutes. 

 Second day: a. m., fed 24 times at average intervals of 2.50 minutes; p. m., fed 

 19 times at average intervals of 3.15 minutes. Third day: fed 23 times at 

 average intervals of 2.61 minutes. The average interval was 3.04 minutes; 

 the longest interval was 15 minutes ; the shortest interval was '^h. minute. 



Assuming that the feeding was done only 13 hours per day, 250 trips were 

 made daily. If young were in nest only 12 days, this would mean about 3,072 

 insects were consumed in addition to what the adults ate. The food for the 

 young seemed to consist mostly of green worms with a few moths and cater- 

 pillars. Obviously this destruction of insect life must have been very beneficial 

 to the near-by apple orchard. 



