NESTING-BOXES 245 



materials which can be utilized in the construction 

 of the nest are put in a conspicuous place which is 

 easily accessible. An examination which the author 

 made of a collection of nests showed that twenty-one 

 species used materials provided for them by man. 

 Horsehair was used by eleven species, strings by 

 seven, mud by four, paper by three, cloth by two, 

 and feathers by two. The Baltimore oriole uses a 

 large amount of such materials as string and yarn; 

 the chipping sparrow nearly always lines its nest 

 with horsehair; robins commonly use pieces of cloth; 

 vireos, the wood pewee, the least flycatcher, and the 

 kingbird may line their nests with cotton batting. 

 ■ Material to be exposed. Some of the materials 

 which may be exposed on fences, bushes, trees, etc., 

 are the following: yarn, string, thread, rags, horse- 

 hair, straw, tufts of cotton and wool, small strips of 

 cloth, pieces of grapevine bark, feathers, cotton 

 batting, and shoemakers' flax. This flax is a good 

 substitute for the plant-fibers which many birds use. 

 The yarn and strings should be of a somber color, 

 and should be cut into lengths of not over twelve 

 inches, lest the birds become entangled and hang 

 themselves. If any of this material is taken by the 

 birds, it furnishes opportunity for locating the nest, 

 so that it may be w^atched and such means taken 

 as may be necessary to protect the occupants. Dur- 

 ing dry seasons, if pans of mud are set in easily ac- 

 cessible and protected places, they may be found and 



