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with their cloisters. Nothing suits thern better than the perpendicular columns and 

 faces of basalt so common in the northern Rockies, against whose black and shining 

 surfaces their villages and the bright inhabitants make a busy and beautiful picture. 

 The eastern half of the country being covered with dense forests, and exposing few- 

 places naturally fitted for a Cliff-Swallow's residence, it appears not to have been gener- 

 ally inhabited by this species previous to the advent of Europeans, and the subsequent 

 preparation of the way for the Swallows by the clearing of the forests and the erection 

 of buildings. At the same time some points widely remote were doubtless occupied by 

 them every summer — for instance, the lofty and cavernous cliffs on the north-eastern 

 shore of Maine and about the Bay of Eundy, and the limestone precipices at Anticosti. 

 It is only knoton, nevertheless, that they bred in early times among the bluffs on Lake 

 Champlain, and that they went each summer to Hudson's Bay. The fact, however, that 

 these Swallows were reported as breeding at these two points among the very earliest of 

 Eastern records, and within a very few years of their discovery by Say in the Rocky 

 Mountains, supports the idea that they had always lived there, but only showed them- 

 selves commonly when settlements brought them into vieAv. It was not until 1S42 that 

 the species appeared in the neighbourhood of New York city. 



" In their wild state, as I have mentioned, these Swallows build their nests against 

 cliffs in companies, constructing them of mud, which is often gathered from a consider- 

 able distance by the industrious birds, all going to the same spot for supplies. "While 

 still wet, it is moulded in the bill into pellets as large as peas, which one by one are 

 plastered into a firmly compacted wall, that is made to assume a shape so symmetrical 

 as to cause us to wonder at the skill of the tiny architect. Normally, this form is that 

 of a chemist's flask or retort— a bulb adhering by its base to the cliff, and terminating 

 outwardly in a contracted horizontal neck, Avhich serves as entrance to the nest, and 

 ordinarily slopes slightly downward, shedding the rain — a disastrous contingency further 

 guarded against in most cases by the choice of a cliff which overhangs at the top. 



" But many circumstances arise to varv the exact design of these mud retorts. In 

 the first place, the character of the foundation must be regarded, an earthen bank not 

 being able to support so long a neck as a roughly rocky wall, to which mud will cling 

 tenaciously. Then, so very social are the birds that they crowd their homes together 

 until every inch of the surface of the cliff for many feet, and often for many yards, square 

 is entirely hidden ; and the structures are so compact that, like the cells in a honeycomb, 

 a single wall answers for two adjoining nests, and little more remains visible of each 

 than the round mouth, which is likely to be misshapen, to adapt it to the irregular room 

 behind. 



" Like other birds, the young Swallows return year after year to the old homestead. 

 But, instead of building on an adjoining section of the cliff, they will found their new 

 nests on the remains of the old, late comers in many cases even building upon and 

 closing over the finished homes and fresh-laid eggs of their precursors. Finally, this 

 accumulation of hundreds of nests becomes too heavy for the foundations to uphold, 



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