74 ANNALS OF BIRD LIFE. 



the mud sometimes will not adhere, and, time 

 after time, the half-built structure falls, the patient 

 architects beginning to repair the damage at once. 

 House Martins are most interesting birds ; and 

 there are few prettier sights in spring-time than to- 

 watch them building their nests or repairing the 

 old ones. Both birds assist in making the nest, 

 and very often one will stay at home to guard and 

 watch whilst the other seeks material. Swallows 

 build in much the same manner, only they prefer 

 a covered site for the nest, in a barn or other out- 

 building. Sometimes it is built upon one of the 

 beams supporting the roof, at others on a stone 

 jutting out of a wall or chimney. The little bits 

 of mud collected by the birds are formed into a 

 shallow cup, and then lined with grass and 

 feathers. The House Martin returns each year 

 and uses its old nest; but the Swallow, though 

 coming back again to its accustomed haunts, 

 generally makes a new home close to the one of 

 the previous season. Both birds assist in making 

 the nest. 



3. Miners. The Sand Martin is certainly the 

 best known little engineer in this department of 

 bird architecture. The earthworks of the Sand 

 Martin may be seen in almost every sandy cliff or 

 steep railway cutting, more especially if such are 

 near to water. The gravel pits and sand quarries 

 are favourite resorts, and as the birds live in 

 colonies, it is easy to watch their lively move- 

 ments during the breeding season. With mar- 



