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LETTER XL. 



To the same. 



SELBORNE, Sept. 2nd, 1774. 



EAR SIR, Before your letter arrived, and of 

 my own accord, I had been remarking and 

 comparing the tails of the male and female 

 swallow, and this ere any young broods 

 appeared ; so that there was no danger of 

 confounding the dams with their pulli : and 

 besides, as they were then always in pairs, 

 and busied in the employ of nidification, there could be no 

 room for mistaking the sexes, nor the individuals of different 

 chimneys the one for the other. From all my observa- 

 tions, it constantly appeared that each sex has the long 

 feathers in its tail that give it that forked shape; with this 

 difference, that they are longer in the tail of the male than 

 in that of the female. 



Nightingales, when their young first come abroad, and are 

 helpless, make a plaintive and a jarring noise; and also a 

 snapping or cracking, pursuing people along the hedges as 

 they walk : these last sounds seem intended for menace and 

 defiance. 



