BIEDS OF NEW YORK STATE 135 



soon as they have dried off and to follow their parents about. 

 Domestic chickens and ducklings are familiar examples of this 

 type of young. 



Grebe 

 Grouse 

 Gallinule 

 Sora 

 Virginia rail 



b Altricial 



Altricial birds are hatched blind and helpless and are cared 

 for in the nest by the parents for a considerable period. The 

 amount of covering varies from that of birds absolutely naked, 

 through that of those having a scant coating of down along the 

 principal feather tracts, to that of those well clothed in down. 

 Their eyes open in a few days and their rate of growth is sur- 

 prising, some ground-nesting species like larks and sparrows 

 having acquired their feathers and being ready to run from the 

 nest in a week. Others, like the hawks and eagles, that must 

 develop large, strong wings before they can leave, remain in the 

 nest for several months. 



Kingfisher, no down Nu KiB3 



Horned larks, little down Nu LdP 



Red-shouldered hawk, much down Nu HP4 



2 Care of young 



a Feeding 



(1) Precocial young 



These young follow their parents about while the latter find 

 food for them and teach them to find it for themselves. 



Virginia rail Nu RV7 



Grebe Nu GsPS 



(2) Altricial young 



The young of this type are fed by their parents during the 

 time they are in the nest and for a considerable period thereafter, 

 (a) Normal method 



Mourning warbler Nu WN 



Louisiana water-thrush Nu WfLS 



At first the parent bird places the food far down in the throat 

 of the young. There is a delicate physiological adjustment 

 between the young bird's stomach and the muscles of its throat 



