70 YOUNG BIRDS. 
Among some species both sexes share equally the task 
of incubation. In others, the female is longer on the 
nest, the male taking her place during a short period each 
day while she is feeding. Less frequently the female is 
not at all assisted by her mate, and in some cases—Os- 
triches, Emus, Phalaropes, and a few others—the male 
alone incubates. 
The Young.—The care of the young and their men- 
tal and physical development afford us unequaled oppor- 
tunities for the study of bird character. We may now 
become acquainted not only with the species but with 
individual birds, and at a time when the greatest demands 
are made upon their intelligence. 
We may see the seed-eaters gathering insects and per- 
haps beating them into a pulp before giving them to their 
nestlings: or we may learn how the Doves, High-holes, 
and Hummingbirds pump softened food from their crops 
down the throats of their offspring. 
The activity of the parents at this season is amazing. 
Think of the day’s work before a pair of Chickadees with 
a family of six or eight fledglings clamoring for food 
from daylight to dark! 
But the young birds themselves furnish far more in- 
teresting and valuable subjects for study. None of the 
higher animals can be reared so easily without the aid of 
a parent. We therefore can not only study their growth 
of body and mind when in the nest and attended by 
their parents, but we can isolate the young of precocial 
birds, such as Chickens, from other birds and study their 
' mental development where they have no opportunity to 
learn by imitation. In this way students of instinct and 
heredity have obtained most valuable results.* 
* Read Lloyd Morgan’s Habit and Instinct (Edward Arnold, New 
York city). 
