A SWIFT-WINGED TRIBE. 113 



Here, on the steep cliffs of tlie ravines and 

 canons, they build nests by the hundreds, liv- 

 ing in colonies. A cliff may have a very 

 warty appearance in spots on account of these 

 nests, which seem to be built in clusters, some- 

 times containing as high as two hundred sepa- 

 rate domiciles. One writer estimates that on 

 the face of a single cliff in Kansas there were 

 between two and three thousand nests. They 

 were gourd-shaped, built of red clay, fastened 

 in the interstices of the rocks, and sparsely 

 lined wdth grass. Now and then a straw was 

 wrought into the masonry. 



While the eave swallows are engaged in 

 house building on the outside of a barn, the 

 barn swallows are often engaged in the same 

 occupation within, building their nests on the 

 sides of logs, rafters, and joists. Mud is also 

 used in these nests, but it is mixed with straw 

 — these birds will not use " bricks without 

 straw " — and the structure is open at the top 

 like the nests of most birds. 



The tails of the barn swallows are deeply 

 forked, which is doubtless an advantage to 

 them in clinging to the sides of the various 

 timbers on which they build. Their flight is 

 also very swift, and the rapidity and precision 

 with w^hich they dash through small holes cut 



