DWELLINGS. 267 



clay, finds itself in possession of a well-made dome. 

 Naturally it prepares an entrance ; the form of this is 

 semicircular. But this is not all. In the interior it 

 arranges two partitions : one vertical, the other hori- 

 zontal, separating off a small chamber. The vertical 

 partition begins at one of the edges of the door, so 

 that the air from without cannot penetrate directly 

 into the dwelling, which is thus protected against 

 extreme variations of temperature. It is in the com- 

 partment thus formed that the female lays her eggs 

 and broods, after having taken care to carpet it with 

 a thick layer of small herbs. 



" In favourable seasons, the Oven-birds begin build- 

 ing in the autumn," Hudson tells us, "and the work is 

 resumed during the winter whenever there is a spell 

 of mild, wet weather. Some of their structures are 

 finished early in winter, others not until spring, every- 

 thing depending on the weather and the condition of 

 the birds. In cold, dry weather, and when food is 

 scarce, they do not work at all. The site chosen is a 

 stout horizontal branch, or the top of a post, and they 

 also frequently build on a cornice or the roof of a 

 house ; and sometimes, but rarely, on the ground. 

 The material used is mud, with the addition of horse 

 hair or slender fibrous rootlets, which make the 

 structure harder and prevent it from cracking. I have 

 frequently seen a bird engaged in building first pick 

 up a thread or hair, then repair to a puddle, where it 

 was worked into a pellet of mud about the size of a 

 filbert, then carried to the nest. When finished the 

 structure is shaped outwardly like a baker's oven, only 

 with a deeper and narrower entrance. It is always 

 placed very conspicuously, and with the entrance 

 facing a building, if one be near, or if at a roadside it 



