54S THE POPULAR SCIENCE MONTHLY 



Pig. 10. Goldfinches Pyramid of Five Young and One Adult at later Stage 

 in Nest-life. Type of direct feeding by regurgitation, where all birds are served at 

 each visit, and some more than once. Note uniformity in response and in size of the 

 nestlings. 



The initial instincts of the young depend upon the degree of de- 

 velopment attained at birth, and are manifested in every phase from a 

 precocious bird like the snipe, which is horn seeing and with a full 

 coat of down, to the altricious cedar wax wing, which is stark naked, 

 and is blind up to the second or fifth day. The precox emerges with 

 feathers wet with the amniotic fluid, and remains at the nest at least 

 long enough to dry off, while the more slowly maturing hawk or eaglet, 

 though down-clad and alert from the first, is tended for weeks or 

 months at the nest. MacPherson, who has described the home life of 

 the golden eagle, which he carefully watched on a cliff in the highlands 

 of Scotland, found that the young were fed at the eyrie eleven weeks 

 before they were ready for independent flight. 



The initial responses of the altrix, of which the cedarbird, and, 

 with some qualification, the cuckoo, may be taken as a type, to be seen 

 at birth or shortly after, are (a) the power of orientation, (6) the 

 grasping reflex of the feet, (c) the food-response, (d) the call note, and 

 (e) the characteristic actions in muting, following feeding, as a result 

 of the stimulus of food, and possibly of the attitude of inspection as- 

 sumed by the adult. Later follow other specific call and alarm-notes, 

 pecking, gaping, stretching, spreading in response to heat, preening, 

 bristling and certain attitudes expressive of fear, flapping and flight. 



