VARIATIONS IN BUILDING. 35 



of these nests which we have seen, we never met 

 with one covered in at top with any sort of material 

 piled up for the purpose by the bird, though we have 

 often observed a tuft of grass, a layer of natural 

 grown moss, or part of the root of a tree projecting 

 over it. 



Some ground builders, which collect few or no 

 materials, are remarkable for the care they display 

 in selecting a convenient locality. In the nest of a 

 peahen, for example, which we lately examined, 

 we observed that the mother bird had taken care to 

 choose a very sheltered spot, the nest being over- 

 hung by a low branch of a spruce fir, which was 

 suspended over it like an umbrella, and completely 

 protected it from rain and dew. Another circum- 

 stance was still more remarkable. It is well known 

 that female birds for the most part wear off a con- 

 siderable portion of the feathers from their breasts 

 by their frequent movements in turning their eggs. 

 Now, as her eggs were placed on the bare earth, no 

 grass growing under the drip of the spruce branch, 

 the breast of our peahen must soon have been rub- 

 bed bare of feathers. Foreseeing this event, as it 

 would appear, the careful creature prepared a soft 

 cushion of dry grass, upon which her breast might 

 rest. This cushion was placed on the most exposed 

 side of the nest, but no part of it under the eggs 

 themselves. 



CHAPTER III. 



MASON BIRDS. 



WHEN the least civilized savages take possession 

 of a natural cavern or the hollow of a tree to shel- 



