1644 U.S. NATIONAL MUSEUM BULLETIN 237 part 3 



Fifth day: The eyes are about half open, but the nestlings still 

 gape at sound rather than sight. Daytime brooding has almost 

 stopped. Barring strong territorial competition with neighboring 

 males, the male will stop singing about this time. 



Sixth day: The eyes are now open and the nestlings will gape at 

 the wave of a hand. The body feathers are beginning to break from 

 their sheaths, but there are bare areas between the feather tracts. 



Seventh day: The young gape at any movement near the nest. 

 The feathers of the back and side are out and the primary sheaths 

 are 10 to 15 millimeters long. The nestlings call when the parents 

 bring food. 



Eighth day: The young now crouch in the nest when disturbed, 

 and can scramble away if placed on the ground outside the nest. 

 The head feathers are out and the primaries beginning to protrude 

 from their sheaths. There are still tufts of down above the eyes 

 and a few bits elsewhere on the body. 



Ninth day: The young are very active, moving around in the nest 

 and preening. They are noisy when the parents bring food. They 

 weight about 14.0 grams, and daily weight gain reduces to about 

 0.7 grams. 



Tenth day. This is the day the young are most likely to leave the 

 nest. K. D. Harris (1944) found the young left in 9, 10, or 11 days. 

 L. J. Moriarty (1965) reports them remaining through the 14th day, 

 when they each weighed 12.21 grams. The young we observed 

 weighed from 15.3 to 16.1 when ready to leave the nest. 



The above account refers to normally developing young. Fre- 

 quently, however, one nestling is smaller than the rest (possibly the 

 last to hatch), and less successful than his siblings in competing for 

 food. He either dies shortly after hatching, or may fall further and 

 further behind to die later in the nestling period. A. D. DuBois 

 (1937) writes: 



"On July 19 I witnessed the removal of the dead fledgling from 

 nest no. 14. It was a surprising feat of strength, for the fledgling 

 was very heavy, being eight or nine days old. Upon rapidly flutter- 

 ing wings the parent rose with his burden straight upward from the 

 nest; then it flew horizontally, and, while flying low, dropped the carcass 

 at a spot about fifty feet away." 



I saw a similar occurrence at Moose Jaw, when a female weighing 

 about 20 grams carried a dead 14-gram nestling for about five feet 

 before dropping it. Another dead young she dragged away from 

 the nest. 



Harris (1944) describes a nest-leaving he witnessed thusly: 



The movement, perhaps stimulated by my activity around the nest, began 

 without warning. The birds suddenly became very restless, kicking violently, 



