THE NUTHATCH. ^11 



brick had been left out. In one of these gaps, measuring 

 about four inches square, I found a complete lining of mud 

 such as I have described. I tried to cat it out entire, but as 

 it was some months since it had been placed there, the mass 

 crumbled to pieces. After this was removed, I got my hand 

 well into the hollow space behind, and turned out all the 

 material I could find. This hole had been used by the birds, 

 as I afterwards learnt from the gardener, for seven or eight 

 years consecutively, which accounted for the large amount of 

 material that had there accumulated. Very few, if any, 

 leaves were used, but a great quantity of the thin scales 

 found on the bark of fir trees, placed together without any 

 particular order so far as one could see. I foand, moreover, 

 two or three eggs which had been buried for some time 

 beneath the pile. There were also in the hole a number of 

 small fragments of wood and bark of various kinds, to 

 which the birds seem to have taken a fancy, as some of them 

 show traces of ornamentation by the birds' bills. Being 

 anxious to obtain a perfect specimen of the plastering work 

 of the nuthatch, I devised the following experiment : 

 before leaving the hole I inserted into it a thin piece of 

 wood curled up into a circular shape, and gave instructions 

 that if the birds placed a lining of mud within it the 

 following year, the wood was to be taken out entire and 

 reserved for me. I was much gratified to find that in the 

 following spring the nuthatches did just what I desired; and 

 moreover, did not forsake their nest, but built up another 

 lining of mud within two days of the removal of their first 

 earthwork. An examination of some fragments of the mud 

 brought together by the nuthatch seems to indicate that the 

 bird knows the value of hair or some other fibrous material 

 in causing the mud to bind firmly en masse. There is a nest 

 of the nuthatch in the South Kensington Museum which was 



