BANK-SWALLOWS. 251 
face will be fairly honey-combed with burrows, so that we 
can readily believe that Mr. Dall counted over seven hun- 
dred holes in one bluff in Alaska. These are usually very 
close together, and the wonder is how the birds ean dis- 
tinguish their own doors. If mistakes do occur, I imagine 
they are all very polite about it, for I know of no more 
peaceable neighbors among birds than they. The mode in 
which this perforation is performed, requiring an amount 
of labor rare with animals, is well described by Mr. Rennie 
in his “ Architecture of Birds :” 
“The beak is hard and sharp, and admirably adapted for 
digging ; it is small, we admit, but its shortness adds to its 
strength, and the bird works..... with its bill shut. This 
fact our readers may verify by observing their operations 
early in the morning through an opera-glass, when they be- 
gin in the spring to form their excavations. In this way 
we have seen one of these birds cling with its sharp claws 
to the face of a sand-bank, and peg in its bill as a miner 
would his pickaxe, till it had loosened a considerable por- 
tion of the hard sand, and tumbled it down among the 
rubbish below. In these preliminary operations it never 
makes use of its claws for digging; indeed, it is impossible 
that it could, for they are indispensable in maintaining its 
position, at least when it is beginning its hole. We have 
