THE OPHIDIA IN THE MONNOW VALLEY. 203 



2. The chances of cxferminntion or survived. — In 

 the case of the adder civilisation is the worst enemy 

 to be feared — man is the greatest danger. It may even 

 be said that, excepting the severity of climatic condi- 

 tions, the adder usually dies a natural death, unless 

 at the hand of man. If, then, the adder has as its 

 habitat a locality where man is chiefly conspicuous 

 by his absence, the chances of survival are at their 

 maximum. This condition is present in the Monnow 

 Valley — that is, man is nearly absent. A few scat- 

 tered farms, mostly rearing cattle and sheep, and 

 therefore with fewer hands than a more corn-growing 

 district, are all that are met with in the way of 

 human habitations in a drive through this valley. 

 The gamekeepers kill a considerable number of 

 adders every spring (the woods on both Garway Hill 

 and The Graig are heavily preserved with pheasants), 

 but apart from this the adder population is very 

 secure. This partly accounts for the exceptional size 

 of adders here : they live to a good old age and attain 

 their full growth. And when it is remembered that 

 twenty female adders will in a season bring forth 

 somewhere about 260 young ones, it is not hard to 

 account for the fact of their being fairly common. 



3. Food-supply. — This is an all-important question 

 in the distribution of a species. It has been seen that 

 the food of adders consisted mainly of mice, slow- 

 worms, small birds and their eggs, newts, water-voles, 

 and grubs. All these are in abundance in this valley, 



