54 NATURAL HISTORY OF SELBORNE, 



your 91 



I am obliged to confess that I know nothing of youi 

 willow-lark. In my letter of April 18th, I had told you 

 peremptorily that I knew your willow-lark, but had not 

 seen it then ; but when I came to procure it, it proved in 

 all respects a very Motacilla trochilus, only that it is a 

 size larger than the other two, and the yellow-green of 

 the whole upper part of the body is more vivid, and the jHI 

 belly of a clearer white. I have specimens of the three 

 sorts now lying before me, and can discern that there are 

 three gradations of sizes, and that the least has black 

 legs, and the other two flesh-coloured ones. The yellowest 

 bird is considerably the largest, and has its quill-feathers 

 and secondary feathers tipped with white, which the others 

 have not. This last haunts only the tops of trees in high 

 beechen woods, and makes a sibilous grasshopper-like noise, 

 now and then, at short intervals, shivering a little with 

 its wings when it sings ; and is, I make no doubt now, 

 the Regulus non cristatus of Ray, which he says " cantat 

 voce striduld locustce." Yet this great ornithologist never 

 suspected that there were three species. 



LETTER XX. 



Selbohne, October Sth, 1768. 



It is, I find, in zoology as it is in botany : all nature is 

 so full that that district produces the greatest variety 

 which is the most examined. Several birds, which are 

 said to belong to the north only, are, it seems, often in 

 the south. I have discovered this summer three species 



