402 BULLETIN 17C, UNITED STATES NATIONAL MUSEUM 



made this very difficult, but the young bird accomplished it, standing 

 literally on its head, braced against the wall of the nest. The dis- 

 charge was projected to a distance of several inches beyond the nest." 

 Mr. DuBois could not mention in his notes the length of time that 

 his young bird remained in the nest, as it died prematurely, but Gladys 

 Hammersley (1928) observed that the altricial period is about 20 

 days ; she writes : 



As the young hummers grew bigger they gradually tramped the nest out of 

 shape, so that when they flew away on June 23rd it was no longer a dainty 

 little cup, but an almost shapeless platform in comparison. There were no fly- 

 ing lessons ; the little hummers buzzed fearlessly out into the world as though 

 they had been accustomed to flying every day of their lives. They were not so 

 expert with their feet, however, maliing several ineffectual attempts before 

 securing a safe landing. I never found any young return to the nest having 

 once left it, but they will return regularly to a chosen perch day after day, 

 even when disturbed several times during the day, generally returning to 

 precisely the same spot on the same twig each time. 



Plumages. — Mr. DuBois says that the young rufous hummingbird, 

 when first hatched, is about as large as a honey bee, nearly black and 

 quite naked, except for two slight tracts of grayish natal down ex- 

 tending longitudinally along the back. It is blind at first, but when 

 six days old a slit begins to show in the membrane covering the eye, 

 and by the twelfth day the eyes are well opened. The natal down 

 grows longer day by day, and pinfeathers begin to show on the sixth 

 and seventh days. From that time on the juvenal plumage continues 

 to grow. 



When fully fledged in fresh juvenal plumage the young male is 

 similar to the adult female, the back largely green, but the upper tail 

 coverts are "cinnamon-rufous" with terminal spots of metallic bronze- 

 green; the throat is dull white, spotted with dark bronzy; the chest 

 is dull white, and the sides and flanks are heavily washed with "cinna- 

 mon-rufous." Usually in August, but sometimes as early as the mid- 

 dle of July, some metallic red feathers begin to appear in the throat, 

 increasing more or less during fall and winter; but I have seen one 

 young male, taken as late as March 17, that still shows no red in the 

 throat, though the back and rump are practically all rufous. The 

 juvenal tail, with terminal white spots on the three outer rectrices 

 somewhat smaller than those of the female, is worn all through fall 

 and winter, until the complete annual molt, late in winter and early 

 in spring, produces the adult plumage ; I have seen one young male, 

 taken on April 15, that was just completing this molt. Young fe- 

 males are like young males but have more green on the back. Adults 

 apparently molt at the same time as young birds, late in winter and 

 early in spring. 



