NA TURAL HISTOR Y OF SELBORNE. 157 



LETTER XVI. 



TO THE SAME. 



SELBORNE, Nov. x>tA, 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 

 monography 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 

 swallow, the swift, and the bank-martin. 



A few house-martins begin to appear about the i6th 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 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 

 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 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 

 forbearance 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 



