196 BIRDS THROUGH AN OPERA-GLASS. 
to those in the hole above them. ‘The flycatchers, 
like the crows and jays, are songless birds; the 
crows and jays are similar to the blackbirds and 
orioles in build and habit; the blackbirds and ori- 
oles are linked with the sparrows and finches by 
the short, conical - billed bobolink and cowbird ; 
the sparrows and finches resemble the tanagers 
in general build; the swallows in No. 6 seem to 
stand alone; but the waxwings resemble the vi- 
reos in elegance and tone of plumage ; the vireos 
approach the wood warblers in size and form; and 
while there is a natural gap between Nos. 9 and 
10, as two families are omitted, the wrens and 
thrashers are like the creepers in shape of bill 
and general coloring; and the creeper is closely 
connected with the nuthatch of No. 12, nut- 
hatches and titmice, while the titmice in their 
turn show the nearness of the family to the king- 
lets. These resemblances, however, are mostly 
superficial, not real. 
The several thrushes are so closely allied that 
there is difficulty in discriminating between them, 
and I confess they puzzled me at first. I began 
by studying the wood, the hermit, and the tawny. 
These three all had brown backs, white speckled 
breasts, and beautiful voices. But before long I 
found they could be easily distinguished by varia- 
tions in the shade of brown on their backs, by 
size and arrangement of the speckles, and by the 
quality of their songs. 
