BANK-SWALLOWS. 251 



face will be fairly lion ej-com bed 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 can 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. Eennie 

 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 



streno^th, 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 



