THE YELLOW-NECKED MOUSE IN SHliOPSHIliE. Ill 



inhabiting the same locality will split into well-marked and 

 distinct species by reason of the preference like has for consorting 

 and breeding with like ? 



To go back to the Yellow-neck in Shropshire. I think that 

 this Mouse and the Long-tail have two migrations — namely, 

 from the neighbourhood of the farm-buildings and stacks in the 

 early summer to the woods and open fields, and a return 

 migration in the late autumn when the supply of berries, etc., 

 runs short. Many, of course, do not leave the woods and hedges, 

 but these are chiefly of the sylvaticus type. I have never caught 

 a Yellow-neck in the open in the winter, though I have taken 

 many Long-tails. And the same applies to the Mice which are 

 ploughed up in the stubbles during the autumn ploughing, 

 many dozen of which have passed through my hands ; but they 

 have all been of the dull, dark sylvaticus type. 



By the way, though the young flavicollis in its first pelage 

 resembles the smaller variety, yet it can easily be distinguished, 

 for the mark across the throat and chest which afterwards 

 becomes the distinctive fawn collar is visible even at this early 

 age as a darkish grey streak. 



Apropos of the difference in size between the adult Mice of 

 the two varieties, I may mention that, whereas the Long-tail can 

 get out easily and without much squeezing through the small 

 wire netting which is known as " ^ in. meshing," yet the 

 Yellow-neck is safely imprisoned by it, and with his bigger skull 

 cannot pass through. As series of measurements may be 

 found in any text-book, I do not propose to give any here, but 

 will only say that in life the difference in size is as obvious as 

 that between a small pony and a big cob. 



The distribution of this handsome Mouse does not seem to 

 be very well worked out. It is known that it is scattered 

 sporadically through the south and west of England, but I am 

 convinced that in many localities it is overlooked, so I should 

 be very glad if anyone who has met with it would communicate 

 with me. 



