VALUE OF BIRDS TO MAN. 43 
blind, and helpless; yet in a few days, or at most a few 
weeks, they have grown to nearly the size of their parents, 
and produced a perfect 
suit of feathers, including 
the strong quills of wings: 
and tail. In a few weeks 
more they are able to 
begin a journey of hun- 
dreds or thousands of 
miles over land and sea, 
in their first migration. 
The young of precocial 
birds, such as Grouse, 
Snipe and Plover, are 
able to run about soon 
after they are hatched. if 
Young Grouse learn to fly Fig. 19.— Young Cedar Birds, less than three 
when quite small, but they aerate 
develop more slowly than do the young of the smaller 
altricial birds. It is difficult, therefore, to determine the 
amount of food they 
require, as they leave 
the nest at once and 
wander from place to 
place, picking up 
their own food. 
The young of the 
altricial perching 
birds, however, re- 
main quite helpless in 
the nest until nearly 
fledged, affording an 
Fig. 20.— Young Grouse, just from the egg, but able excellent opportunity. 
ass for the investigator 
to determine the amount and character of their food, and 
to watch the progress of their development. We can learn 
how much food such young birds require by feeding them 
in confinement. 
