Tue PercHINnG Birpbs. 45 
the eye and not the ear. We have seen that the win- 
ter-wren sings only during nesting-time; but no such 
matter affects the Carolina. It is just as lively in 
January as in June, and I shall long remember one 
bitter cold morning, when a cardinal grosbeak on 
one side of the river, there nearly a mile wide, was 
answered by a wren on the opposite shore. It may 
have been a mere coincidence, of course, but the 
effect was that of giving and returning a challenge, 
and the clear, sweet notes of the two songsters rang 
out in the still, frosty air as distinctly as the cawing of 
the crows that filled the river valley. Nuttall gives an 
elaborate description of the bird’s song, and speaks of 
the imitation of the notes of this and that bird, giving 
details so minutely that the thought arises, Has the 
habit of the bird undergone a change? Its range ap- 
pears to have done so, for it is now very common in 
New Jersey and does not seem to stray atall. In the 
hills of the upper Delaware Valley, in May, 1892, I 
found them very abundant, and one pair at least were 
nesting on a shelf of rock overhung by a jutting mass 
of stone. It was the most open nest I had ever seen. 
Others of these birds were clambering in and out 
among the rocks, and doubtless other nests were near, 
but in more secluded positions. 
The banks of streams are favorite localities, and 
I have sometimes seen the birds hop upon a muddy 
flat as if looking for food, but such a change is un- 
common. They prefer climbing or clinging when 
not on the wing, and no position seems unsuitable for 
singing. 
This bird is one of many that sing at night. Not 
