BANK SWALLOW. 597 



Habits. — The Bank Swallow, which differs essentially in 

 some of its habits from our other species, arrives about the 

 same period as they, and although in one sense more local, is 

 yet more extensively distributed, as it occurs in the most re- 

 mote parts of Scotland, as well as in the most southern of 

 England, and even frequents the sandbanks on the shores of 

 the northernmost Hebrides, where neither the other Swallows 

 nor the Swift are ever seen. Immediately after its arrival, 

 it betakes itself to the stations in which it intends to reside 

 during the season, unless the weather happens to be very 

 severe, in which case it remains for a time in some sheltered 

 hollow, where the insects are most numerous. 



Wherever a perpendicular section of diluvium is made, whe- 

 ther by natural causes, or, as is more frequently the case, by ar- 

 tificial excavations, colonies establish themselves, proportionate 

 in numbers to the facilities afforded for lodging themselves, and 

 sheltering their nests. Steep banks of rivers, sand-pits, quar- 

 ries, and faces made in the soft soil by the action of the sea, are 

 the places in which they are usually found. Sand, gravel, clayey 

 diluvium, or loam, are all adapted for their purpose ; and, al- 

 thouofh instances of their breeding in holes in walls and old 

 buildings are sometimes met with, they are extremely rare. 

 They seldom appear in cities, unless one of their breeding 

 places be in the immediate vicinity ; nor do they seek the 

 neighbourhood of man, but prefer the most sequestered spots, 

 on dry heaths or in valleys, although they are not met with 

 in the ravines or glens of our more elevated mountainous dis- 

 tricts. It has been alleged that they prefer the vicinity of 

 lakes and streams, and White asserts " that no instance oc- 

 curs of their abounding but near vast pools or rivers ; and, in 

 particular, it has been remarked that they swarm in the banks 

 of the Thames, in some places below London Bridge." But 

 when I consider the places in which I have met with them, 

 as the banks of sea-sand in the island of Harris, a clayey bank 

 on the sea shore near Portobello, various parts of the diluvial 

 banks of the Dee and Spey, the clinkstone quarries of Black- 

 ford Hill, various sandstone quarries and sand-pits near Edin- 

 burgh, and other localities, T nuist come to a different conclu- 



