460 BULLETIN 17 6, UNITED STATES NATIONAL MUSEUM 



ning, she devoted 7 hours 47 minutes to warming her eggs, while 

 3 hours 69 minutes were spent away from the nest. 



Wlien at length they are hatched, the new-born hummingbirds 

 appear more like black grubs than the nestlings of a feathered crea- 

 ture. Their eyes are completely hidden by the tightly closed lids; 

 the bill is represented by a mere bump; and the line of sparse brown 

 fuzz along the center of the back does little to cover their bareness. 

 They seem very small and very naked to survive the cold blustery 

 days that during November and December are frequent on the higher 

 mountains where they are raised. During the nights they are well 

 protected from exposure, for their downy nests are thick-walled and 

 warm, and their mother fits into the space above them as snugly as 

 a cork in the mouth of a bottle, maintaining the vital spark within 

 her children by means of her own marvelous capacity for heat pro- 

 duction. It is during the day that the endurance of the nestlings is 

 put to the most severe test, because they must be left uncovered at 

 intervals while the mother forages for food. If ever nestlings seem 

 to need the ministrations of a father, to help feed them and to warm 

 them while the mother takes her recesses and seeks her food, it is 

 these little hummingbirds; yet no male ever appears to aid in their 

 care, for this is not the custom among hummingbirds. On cruel days 

 when a wind that is half a gale drives the chilling cloud mist through 

 the treetops and whips the limber branches that support the nests, 

 one marvels that such minute creatures, smaller even than a honey 

 bee, can maintain the temperature of their bodies above the death 

 point, even during the few minutes for which they are left exposed 

 wliile the mother forages. Sometimes, indeed, a tiny hummer only 

 a few days old is found dead in its« nest, apparently having suc- 

 cumbed to the inclement weather, in spite of the devoted attention 

 of the mother. 



Before the nestlings are large and strong enough to raise up and 

 eject their droppings beyond the rim of the nest, these are removed 

 from the interior by the mother, who, standing on the rim, grasps 

 the particles between the tips of her mandibles and throws them out by 

 sideways jerks of her heard, or else swallows them, and by this means 

 keeps the nest decently clean. When they are slightly older, the 

 young hummers barely manage to deposit their excrement on the 

 rim, and then the parent, less careful than most passerine birds in 

 the sanitation of her nest, no longer takes the trouble to remove it. 

 Finally, with increasing size and strength, the nestlings are able to 

 eject their droppings beyond the rim of the nest and no longer soil it. 



When the young hummingbirds are seven or eight days old their 

 pinfeathers begin to sprout. At the age of nine or ten days the eye- 

 lids begin to part, and the brown tips of the feathers to peep from 



