The Birds’ Calendar 
eluding observation, not only by placing them 
in concealment, but by making the exterior of 
the nest so harmonious in color and texture 
with its surroundings, that it is sometimes 
scarcely discernible even when close before 
your eyes. It often seems as if the chronic 
anxiety and ceaseless vigilance of these creat- 
ures to escape destruction would make life 
hardly worth living. 
Even in winter, 
‘* When there is a hush of music on the air,” 
you commonly hear a chirp or zip before you 
see the bird, and not infrequently these call- 
notes are distinctive enough to indicate the 
species. This is perhaps especially true of the 
winter birds, when the various families are rep- 
resented by so few species, and the more re- 
mote the relationship the more unlike the notes 
are likely to be. For example, the white- 
throated sparrow has a peculiar and unmistak- 
able tone, soft, but shrill, as unlike that of the 
cardinal grosbeak or of the nuthatch as possible, 
although not easily distinguished from the note 
of some of the species appearing later in the 
season. Indeed, without these faint sugges- 
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