186 MISCELLANEOUS OBSERVATIONS. 



the dirty pools in St. George's Fields, and about Whitechapel. 

 The question is where these build, since there are no banks 

 or bold shores in that neighbourhood ? Perhaps they nestle 

 in the scaffold-holes of some old or new deserted building. 

 They dip and wash as they fly sometimes, like the house- 

 martin and swallow. 



Sand-martins differ from their congeners in the diminu- 

 tiveness of their size, and in their colour, which is what is 

 usually called a mouse-colour. Near Valencia, in Spain, 

 they are taken, says Willughby, and sold in the markets for 

 the table, and are called by the country people, probably 

 from their desultory, jerking manner of flight, Papillon de 

 Montagna. 



LETTER LX. 



TO THOMAS PENNANT, ESQ. 



SELBORNE, Sept. 2, 1774. 



DEAR 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 

 observations, 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. 



The grasshopper-lark chirps all night in the height of 

 summer. 



