BIRDS OF THE AIR. 249 



thousands, all swarming with these lively birds, who 

 built their nests on the horizontal beams that supported 

 the barn roof. The birds left us when they were de- 

 prived of their tenements, while the Cliff-Swallow, that 

 builds under the eaves of barns and houses and under 

 projecting cliffs of rocks, has increased, feeding upon the 

 larger quantity of insects consequent upon the absence 

 of the Barn-Swallow. 



This species is of a social habit ; fond of building and 

 breeding, as it were, in small communities. An old- 

 fashioned barn has been known to contain as many as 

 two dozen nests. They are constructed of materials simi- 

 lar to those of a Eobin's nest ; but the Swallow adds to 

 the lining of grass a few feathers, which the Robin does 

 not use. Dr. Brewer alludes to a custom among the Barn- 

 Swallows of building " an extra platform against, but dis- 

 tinct from the nest itself, designed as a roosting-place for 

 the parents, used by one during incubation at night or 

 when not engaged in procuring food, and by both when 

 the young are large enough to occupy the whole nest." 

 The eggs of the Barn-Swallow are nearly white, with a 

 fine sprinkling of purple. Two broods .are reared in a 

 season. When the bird appears to have a third brood I 

 think it must have happened from the accidental destruc- 

 tion of the second brood of eggs. 



THE CLIFF-SWALLOW. 



The Cliff-Swallow is the species that has apparently 

 filled the vacancy made by the diminished numbers of the 

 Barn- Swallow. It is a smaller bird and more whitish 

 underneath. The nests of this species are placed under 

 the eaves of houses, sometimes extending nearly across 

 the whole side of a roof, resembling in some degree a 

 long row of hornets' nests. The nest is of a roundish 

 11* 



