1226 U.S. NATIONAL MUSEUM BULLETIN 237 part 3 



they were fed 11 times in 100 minutes, an average of once every 9.1 

 minutes. At 7 and 8 days of age they were fed 25 times in 253 

 minutes; the shortest interval between feedings was 1 minute, the 

 longest 23 minutes, and the average 10.1 minutes. Young were also 

 fed more often late in the day than at mid-day. Three young about 

 6 days old in a nest I watched in early August between 7 :50 and 8 :20 

 p.m. were fed 7 times or once every 4.2 minutes. 



Lynds Jones (1913) watched a pair of field sparrows feeding foiu- 

 6- to 8-day-oId nestlings for 19 hours and 12 minutes. "During that 

 time 237 pieces of food were delivered and 31 excreta removed. The 

 shortest time between feedings was one minute and the longest 21 

 minutes, the average being 10 minutes between feedings. If each of 

 the four young were [sic] fed in regular rotation each received food 

 once in 40 minutes. There were 154 Geometrid larvae (104 green, 

 37 brown, 13 white), 45 grasshoppers, 24 moths, 3 scattering, and 

 11 unknown." 



Undisturbed young usually left the nest when between 7 and 8 days 

 of age, and when distm-bed, often at 6 days. The departing fledglings 

 hopped first to the nest rim, then to the ground. When disturbed 

 they often erupted from the nest in a group, tumbling out awkwardly, 

 each heading in a different direction. They usually hopped unsteadily 

 on the ground a short distance and then stopped. Sometimes the 

 female would lead them farther away from the nest and then leave 

 them. They kept within their own territories as a rule, and seldom 

 wandered into neighboring ones. 



After leaving the nest the young remain near it on the ground or in a 

 low bush, where the parents feed them about once every 5 to 10 min- 

 utes. If they are not fed often enough they begin to "chip," which 

 they never do in the nest, and the parents seem to try to keep them 

 quiet by continuous feeding. When they have been out of the nest 

 5 days they can fly short distances, but the parents still keep them 

 together in their territory. The male now assumes more and more of 

 the care of the nestlings, and all of it when the female starts to renest. 



By the time the young are 25 days old, their tails have reached 

 approximately adult length, and shortly thereafter they are on their 

 own. Malcolm Crooks (MS.) gives the age of independence in Iowa 

 as attained between 26 and 34 days. I have watched adults feeding 

 young from 25 to 30 days of age at different nests gradually acquii'ing 

 their independence. At this point in my study area the young 

 gathered in small flocks of 10 to 12 individuals in the dense thickets of 

 hawthornes in the general nesting area. The male field sparrows to 

 whom the territories belonged did not bother them, and the young 

 birds, now fully grown, fed and played together, often flying up and 

 down at each other, and then returning to perch in the hawthornes. 



