266 



NATURAL HISTORY 



few days later than the swallow. For some 

 time after they appear, the hirundines in 

 general pay 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 tex- 

 ture after it has been so long benumbed by 

 the severities of Winter. About the mid- 

 dle of May, if the weather be fine, the 

 martin begins to think in earnest of pro- 

 viding 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 to- 

 gether with 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 

 foundation firmly fixed, so that it may 

 safely carry the superstructure. On this 

 occasion the bird not only clings with its 

 claws, but partly supports itself by strongly 

 inclining its tail against the wall, making 



