28 BIRDS OF FI ELD, FOREST AND PARK 



for prowling cat, squirrel or snake has little 

 chance of entering. These birds may be classed 

 as good engineers. 



Eave Swallows are good masons. From the 

 mud-puddle in the clay road they roll up little 

 pellets which are placed one upon another like 

 bricks, making a strong structure when the 

 material is thoroughly dry. Sometimes a colony 

 of a score or more build a sort of tenement 

 house, but each dwelling has its own entrance. 

 Barn Swallows use the same material, but 

 usually place the nest on the beams or rafters of 

 a barn, or other outbuilding of the farm, lining 

 it with hens' feathers. Rarely one sees a nest 

 of this Swallow on the outside of a building. 



The Orioles are very skillful builders, weav- 

 ing a fine, bag-shaped nest of strings, grass and 

 tendrils, which they suspend from the end of 

 some slender bough, usually of an elm tree, 

 where it swings and sways in the summer 

 breezes, its inmates quite safe from danger in all 

 forms. Sparrows build substantial nests of root- 

 lets, grasses, hair, wool, etc., on the ground, or 

 in low bushes, as the case may be. Our old friend, 

 the Robin, builds a rough but substantial nest 

 of mud and straw, shaping it with her breast. 

 Hawks, Owls and Crows build large nests of 

 coarse sticks, usually in forest trees that are 

 quite inaccessible. The Marsh Hawk, however, 

 builds on the ground. 



The nesting habits of birds change with vary- 

 ing conditions as to surroundings. Chimney 

 Swifts and Tree Swallows formerly nested in 

 hollow trees, but with the disappearance of the 



