APPENDIX. 
BILL OF CROSSBILL, p. 124. 
This bird so seldom breeds in this country, that oppor- 
tunities for examination are very rare, and in reference to the 
crossing of the mandibles, since the text was written I have 
met with a notice by Mr. Blyth, of a nest of the common 
species that was taken in the vicinity of Sevenoaks. The 
young birds, four in number, were haif fledged when found, 
and were uniformly brown in colour; but the most noticeable 
peculiarity was that the mandibles of each were as much 
crossed as those of the adults. This, therefore, confirms the 
opinion I have expressed that this is their normal form. The 
straight mandibles of the young one mentioned by Yarrell 
must be considered an exception, and indeed were literally 
deformed. | 
NUTHATCH, p. 150. 
I have lately noticed a peculiarity in the mode in which 
the Nuthatch gives the heavy blows necessary to penetrate the 
thick-shelled nuts. The bill is particularly thick and strong 
for so small a bird, and approaches in character the wedge- 
shaped bill of the woodpeckers. Formidable as this weapon 
is, its efficiency is increased by the singular manner in which 
it is sometimes used. The bird seems to have an idea when 
additional force is required, and instead of striking with the 
bill by the movement of the neck alone, it throws the whole 
weight of its body into the blow, turning itself as it were 
into the head of a hammer, which swings upon the feet as a 
pivot. 
