152 NATURAL HISTORY 



LETTEE XVI. 



TO THE SAME. 



Selborne, Nov. 23, 1773. 

 DEAR SIR, 



IN obedience to your injunctions I sit down to give you some 

 account of the house-martin, or martlet ; and, if my mono- 

 graphy of this little domestic and familiar bird should happen 

 to meet with your approbation, I may probably soon extend 

 my inquiries to the rest of the British hirundines the swal- 

 low, the swift, and the bank-martin. 



A few house-martins begin to appear about the sixteenth of 

 April; usually some 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 it's 

 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 man- 

 sion for it's 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 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 it's utmost efforts to get the first 

 foundation firmly fixed, so that it may safely carry the super- 

 structure. On this occasion the bird not only clings with it's 

 claws, but partly supports itself by strongly inclining it's 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 it's own weight, the provident ar- 

 chitect has prudence and forbearance enough not to advance 

 her work too fast ; but by building only in the morning, and 



