THE PERCHING BIRDS. 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 at all. 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 



