SAND MARTIN. 229 



tions of men, its annual return is not so regularly or so 

 generally noticed. Mr. Heysliam, however, has recorded 

 that so far north as Carlisle, this bird has in two different 

 seasons been noticed before the end of March ; and there arc 

 other records of its having been observed in Cumberland on 

 the 4th, and on the 11th of April. 



Like the species already described, this little wanderer 

 comes to this country from Africa, and frequents as its nest- 

 ing-place high banks of rivers, sand-pits, and other vertical 

 surfaces of earth that are sufficiently soft in substance to 

 enable the bird to perforate it to the depth necessary for its 

 purpose. In such situations this little engineer forms cir- 

 cular holes in a horizontal direction, boring to the depth of 

 two feet or more, with a degree of regularity, and an amount 

 of labour, that is rarely exceeded among birds. The mode 

 in which this perforation is accomplished has been well de- 

 scribed by Mr. Rennie in his architecture of birds, in the 

 following terms, page 18 : — " The beak is hard and sharp, 

 and admirably adapted for digging ; it is small, Ave admit, but 

 its shortness adds to its strength, and the bird works, as we 

 have had an opportunity of observing, with its bill shut. 

 This fact our readers may verify by observing their opera- 

 tions early in the morning through an opera glass, when they 

 begin 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 sandbank, and peg in its bill as a miner would 

 do his pickaxe, till it had loosened a considerable portion of 

 the hard sand, and tumbled it down amongst the rubbish 

 below. In these preliminary ojierations it never makes use 

 of its claws for digging ; indeed, it is impossible it could, 

 for they are indispensable in maintaining its position, at 

 least when it is beginning its hole. We have further re- 

 marked that some of these Martins' holes are nearly as cir- 

 cular as if they had been planned out with a pair of com- 



