OF SELBORNE. 1/53 



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 work- 

 men 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 it's own weight. By this method in about ten or 

 twelve days is formed an hemispheric nest with a small aper- 

 ture towards the top, strong, compact, and warm ; and per- 

 fectly fitted for all the purposes for which it was intended. 

 But then nothing is more common than for the house-spar- 

 row, as soon as the shell is finished, to seize on it as it's own, 

 to eject the owner, and to line it after it's own manner. 



After so much labour is bestowed in erecting a mansion, as 

 Nature seldom works in vain, martins will breed on for seve- 

 ral years together in the same 'nest, where it happens to be 

 well sheltered and secure from the injuries of weather. The 

 shell or crust of the nest is a sort of rustic work full of knobs 

 and protuberances on the outside : nor is the inside of those 

 that I have examined smoothed with any exactness at all ; but 

 is rendered soft and warm, and fit for incubation, by a lining 

 of small straws, grasses, and feathers ; and sometimes by a bed 

 of moss interwoven with wool. In this nest they tread, or 

 engender, frequently during the time of building ; and the 

 hen lays from three to five white eggs. 



At first when the young are hatched, and are in a naked 

 and helpless condition, the parent birds, with tender assiduity, 

 carry out what comes away from their young. Was it not 

 for this affectionate cleanliness the nestlings would soon be 

 burnt up, and destroyed in so deep and hollow a nest, by their 

 own caustic excrement. In the quadruped creation the same 

 neat precaution is made use of; particularly among dogs and 

 cats, where the dams lick away what proceeds from their 

 young. But in birds there seems to be a particular provision, 

 that the dung of nestlings is enveloped into a tough kind of 

 jelly, and therefore is the easier conveyed off without soiling 

 or daubing. Yet, as nature is cleanly in all her ways, the 

 young perform this office for themselves in a little time by 



