NATURAL HISTORY OF SELBORNE. 45 



NOTES TO LETTER XII. 



1 The harvest mouse is the smallest of British animals. Unlike its relatives, 

 it builds its nest on the stalks of grass or corn at a little distance from the 

 ground. The nest is globular in shape, made of woven grass, and has a small 

 entrance like that of a wren's. It is tolerably common in some of the southern 

 counties, but it is not easily found. 



2 There was a pool in Shropshire where I used to fish for roach, and I was 

 always struck with the number of swallows which roosted on the willow bushes 

 fringing the banks. One could almost take them in one's hand. At Acle, 

 in Norfolk, one August, the swallows roosted on the telegraph wires in such 

 extraordinary numbers that they formed continuous black festoons as far as the 

 eye could reach. 



LETTER XIII. 



SELBORNE, Jan. 22nd, 1768. 



SIR, As in one of your former letters you expressed the more 

 satisfaction from my correspondence on account of my living in 

 the most southerly county ; so now I may return the compliment, 

 and expect to have my curiosity gratified by your living much 

 more to the North. 



For many years past I have observed that towards Christmas 

 vast flocks of chaffinches have appeared in the fields ; many more, 

 I used to think, than could be hatched in any one neighbourhood. 

 But, when I came to observe them more narrowly, I was amazed 

 to find that they seemed to me to be almost all hens. I com- 

 municated my suspicions to some intelligent neighbours, who, 

 after taking pains about the matter, declared that they also thought 

 them mostly females, at least fifty to one. This extraordinary 

 occurrence brought to my mind the remark of Linnaeus, that 

 " before winter all their hen chaffinches migrate through Holland 



