EASTERN AND CANADIAN CHIPPING SPARROWS 1173 



brought food to the nest, the female flew off, and he fed the hatchlings. 

 In the second instance the male bronglit food and gave it to the female 

 on the nest; she then hopped up on the rim and, while the male stood 

 by, fed the newly hatched young. In nests that I have observed the 

 male did most of the feeding for the first few days, and the female 

 brooded the young. Toward the end of the 3rd day she brooded less 

 and fed the young more often, until, by the last days before the young 

 fledged she brought food as often as the male. The rate of feeding 

 ranged from 2 trips per hoiu* the first day to 17 per hour toward 

 the end of the nesting period. Some individual differences occur 

 in the roles of male and female in the early feeding. In a nest ob- 

 served by Bradley (1940) the pattern was the same as in those I 

 watched, but Walkinshaw (1944b) reports a nest where the female did 

 nearly all the early feeding. This was an August nest when the 

 pattern may be somewhat different, especially when the male is 

 still tending young from a previous nesting. 



The female does most of the brooding. Walkinshaw (1944b) found 

 that "on a cool morning the male occasionally brooded for a very few 

 minutes." On the first day the young are brooded about 90 percent 

 of the time. This declines until after the 4th day there is little brood- 

 ing, except when the sun is directly on the nest, at which time the 

 female often stands over the young. 



Weed (1898) recorded the activity at a nest containing three young 

 that fledged 2 days later. The observations were made on June 22 

 and extended from 4:06 a.m., when the brooding parent first left the 

 nest, until 7:50 p.m., when a parent settled dovra for the next night of 

 brooding. Dui'ing this period of nearly 15^ hours the parents fed 

 the young 189 times. During the first hour they were fed 13 times. 

 The lowest number of feedings was betAveen 6 :00 and 7 :00 a.m. when 

 there were 7 trips; the highest was 21 trips between 1:00 and 2:00 

 p.m. During the last hour of the day the rate was the same as for the 

 first, 13 times. 



William R. Dawson and Francis C. Evans (1957) conducted a study 

 on the growth and development of nestling field and chipping sparrows. 

 At hatching the muscular sj-stem is poorly developed and the nestlings 

 remain inactive except for gaping for food. The muscular system 

 develops rapidly and by the 4th day they can hold up their heads and 

 are attempting to stand. The capacity for temperature regulation 

 begins to appear on the 5th day and it is quite effective by the 6th. 

 On the 7th the birds are "essentially homeothermic." Dawson and 

 Evans report that on the 6th day they were so active they had to be 

 confined to boxes to prevent escape. I found that in northern 

 Minnesota the 6th day is the best time to band nestlings, for at that 

 age they are large enough to band and may still be easily returned to 



