152 NATURAL HISTORY OF SELBORNE. 



no attention to the business of nidification, but play and 

 sport about, either to recruit from the fatigue of their 

 journey, if they do migrate at all, or else that their blood 

 may recover its true tone and texture after it has been so 

 long benumbed by the severities of winter. About the 

 middle of May, if the weather be fine, the martin begins to 

 think in earnest of providing a mansion for its family. 

 The crust or shell of this nest seems to be formed of such 

 dirt or loam as comes most readily to hand, and is tempered 

 and wrought together vv^ith little bits of broken straws to 

 render it tough and tenacious. As this bird often builds 

 against a perpendicular wall without any projecting ledge 

 under, it requires its utmost efforts to get the first founda- 

 tion firmly fixed, so that it may safely carry the superstruc- 

 ture. On this occasion the bird not only clings with its 

 claws, but partly supports itself by strongly inclining its 

 tail against the wall, making that a fulcrum ; and thus 

 steadied, it works and plasters the materials into the face 

 of the brick or stone. But then, that this work may not, 

 while it is soft and green, pull itself down by its own 

 weight, the provident architect has prudence and forbear- 

 ance enough not to advance her work too fast ; but by 

 building only in the morning, and by dedicating the rest of 

 the day to food and amusement, gives it sufficient time to 

 dry and harden. About half-an- inch seems to be a sufficient 

 layer for a day. Thus careful workmen, when they build 

 mud-walls (informed at first perhaps by this little bird), 

 raise but a moderate layer at a time, and then desist, lest 

 the work should become top-heavy, and so be ruined by its 

 own weight. By this method in about ten or twelve days 

 is formed a hemispheric nest with a small aperture towards 

 the top, strong, compact, and warm ; and perfectly fitted 

 for all the purposes for which it was intended. But then 



