32 THE HUMAN SIDE OF BIRDS 



of its feathers, is the casarita, which means 'little 

 house-builder." The nest of the casarita is usually- 

 found at the bottom of a cylindrical tube which ex- 

 tends from five to six feet underground. This bird 

 is common in the La Plata region of South Amer- 

 ica, and boys who attempt to dig out the nests are 

 rarely ever successful, owing to the length of the 

 tube. An unusual thing about this otherwise in- 

 telligent little creature is its absolute incapacity 

 for acquiring any ideas of thickness. It will con- 

 tinually attempt to bore nests in thin walls, with 

 apparent surprise when daylight is reached on the 

 opposite side! 



The custom of building mounds for nesting- 

 places has been extensively adopted by many spe- 

 cies of birds in Australia and elsewhere. The 

 mallee-bird makes a mound or nest in the most pe- 

 culiar way by bringing together gravel and vegeta- 

 ble matter. These are mixed almost in the same 

 manner as a brick-maker mixes his mud and straw ; 

 and as the vegetable matter decays a sufficient 

 amount of heat is produced to hatch the eggs. 



Dr. Grey informs us that the mallee's nest oc- 

 casionally measures thirteen yards about the base 

 and is about two feet in height. In a letter in 1842 

 he wrote: "The mound appears to be constructed 

 as follows: A nearly circular hole, about eighteen 



