FACTORS IN ANIMAL LIFE 
and reared by the sparrow, or the warbler, or the 
vireo does not sing the song of the foster-parent. 
Why? Did its parent not try to teach it? I have no 
evidence that young birds sing, except occasionally 
in a low, tentative kind of way, till they return the 
following season, and then birds of a feather flock 
together, robins staying with robins, and cowbirds 
with cowbirds, each singing the song of its species. 
The songs of bobolinks differ in different localities, 
but those of the same locality always sing alike. I 
once had a caged skylark that imitated the songs 
of nearly every bird in my neighborhood. 
Mr. Leander S. Keyser, author of “Birds of the 
Rockies,” relates in “Forest and Stream” the re- 
sults of his experiments with a variety of birds taken 
from the nest while very young and reared in cap- 
tivity; among them meadowlarks, red-winged black- 
birds, brown thrashers, blue jays, wood thrushes, 
catbirds, flickers, woodpeckers, and several others. 
Did they receive any parental instruction? Not a 
bit of it, and yet at the proper age they flew, perched, 
called, and sang like their wild fellows — all except 
the robins and the red-winged blackbirds: these 
did not sing the songs of their species, but sang 
a medley made up of curious imitations of human 
and other sounds. And the blue jay never learned 
to sing “the sweet gurgling roulade of the wild 
jays,” though it gave the blue jay call correctly. Mr. 
Keyser’s experiment was interesting and valuable, 
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