140 NATURAL HISTORY 



distant regions, such as South America, the coast of 

 Guinea, &c. were thick-billed birds of the Loxia and 

 Fringilla genera ; and no Motacillce or Muscicapce, were 

 to be met with. When I came to consider, the reason 

 was obvious enough ; for the hard-billed birds subsist 

 on seeds which are easily carried on board ; while the 

 soft-billed birds, which are supported by worms and 

 insects, or, what is a succedaneum for them, fresh raw 

 meat, can meet with neither in long and tedious voy- 

 ages. It is from this defect of food that our collections 

 (curious as they are) are defective, and we are deprived 

 of some of the most delicate and lively genera. 



I am, &c. 



LETTER XXXI. 



TO THE SAME. 

 DEAR SIR, SELBORNE, Sept. 14, 1770. 



You saw, I find, the ring-ousels again among their 

 native crags ; and are farther assured that they continue 

 resident in those cold regions the whole year. From 

 whence then do our ring-ousels migrate so regularly 

 every September, and make their appearance again, as 

 if in their return, every April? They are more early 

 this year than common, for some were seen at the usual 

 hill on the fourth of this month. 



An observing Devonshire gentleman tells me that 

 they frequent some parts of Dartmoor, and breed there ; 

 but leave those haunts about the end of September or 

 beginning of October, and return again about the end 

 of March. 



Another intelligent person assures me that they breed 

 in great abundance all over the Peak of Derby, and 

 are called there Tor-ousels ; withdraw in October and 



