THE NATURAL HISTORY OF NESTS 163 



martin is the nest of some of the South American oven- 

 birds (Furnarius) for instance, of that species (F. rujus) 

 which is called the " hornero " or baker. The nest is about 

 the size of a child's head, and may weigh 8 to 9 Ib. ; it is built 

 in a conspicuous place on a tree, or post, or house-roof. 

 It is made of mud and dung strengthened, as in the swallow 

 and martin, with some hair or dry grass, which is also used 

 as an internal lining. The walls are of almost brick-like 

 strength when well baked, and it is sometimes the work of 

 months to build them. The oven-bird's bill is quite small, 

 and it has to work slowly, pellet by pellet ; moreover, 

 when dry weather sets in, it is difficult to get material. 

 But the chief peculiarity of the nest is the presence of an 

 inner chamber ; there is an anteroom and a bedroom, as 

 Prof. Trail neatly puts it. 



On a different line of evolution, though there is no lack 

 of connecting links, are the felt -work nests, cleverly made of 

 interwoven vegetable fibres and hair in both cases a good 

 non-conducting material. Chaffinch and goldfinch make 

 open felt-work nests, which may be eked out with spiders 1 

 webs and often beautifully disguised with moss and lichen. 

 Similar constructions, masterpieces of skill, are domed in the 

 wren and the bottle titmouse, slung like a hammock in the 

 gold-crest, suspended by a string in certain grossbeaks and 

 humming-birds. There seems to be no doubt that the nest is 

 sometimes balanced with lumps of earth an extraordinary 

 device, when one comes to think of it. 



Among these built nests there are endless refinements of 

 detail. The entrance may be narrowed ; the outside may 

 be masked ; the whole may be swung so loosely that no 

 snake could possibly enter ; the lining may be made like a 

 bed of down : thus MacGillivray counted 2379 feathers in 

 the nest of the long-tailed tit. In the nest of the common 

 thrush, which is plastered internally with rotten wood 



