THE ANIMAL KINGDOM. 287 



there is a web-footed bird which hollows out a kind of oven 

 under the soil, in which incubation takes place. An Ameri- 



138. Burrowing-Owl : Strix cuniculnria (Ch. Bonaparte), and Section of its Burrow. 



can sparrow is still more ingenious ; it builds one. It is a 

 regular mason, and ' hence the name of oven-builder has 

 naturally been given to it. It is a more robust workman 



