72 ANNALS OF BIRD LIFE. 



nest. Wood, in preventing the escape of heat, is 

 therefore the best material possible for the incuba- 

 tion of eggs, especially at a time when the atmo- 

 sphere is chilly, and often charged with moisture ; 

 for the Song Thrush is one of .the earliest birds to 

 breed in the spring. All the other species of 

 British Thrush plaster their nests, but not so 

 much as the preceding bird. They make their 

 nest in a precisely similar manner : first the grass 

 stage, then a plastered coating of mud, but finish 

 off with a final lining of dry grass. The Missel- 

 thrush perhaps uses more mud in the fabrication 

 of its nest than any other member of this family. 

 Another plasterer is the Kittiwake Gull. This 

 bird builds its nest upon the jutting prominences 

 of the steep ocean cliffs, forming it of turf and 

 roots with the soil adhering to them, which are 

 tramped and beaten with its wet feet, aided by 

 the salt spray, into a mortar-like mass which in 

 time becomes very solid and firm. Upon this 

 foundation a further nest is made of seaweed, 

 marine herbage, dry grass, and sometimes a few 

 feathers. The Nuthatch is also very expert at 

 plastering. This bird generally breeds in a hole 

 of a tree, and usually plasters up most of the 

 openings with clay, only leaving sufficient room for 

 ingress. This curious little bird has been known 

 to collect as much as eleven pounds of clay to 

 plaster on its nest. 



2. Masons. From the plasterers we will now 

 turn to the masons. Most interesting of these 



