128 CALIFORNIA MAMMALS. 



trap bedded so that the pan is level with the runway will usually 

 prove successful. Where they are very abundant a narrow trench 

 dug across the runway, a foot or so deep with straight sides, and 

 visited night and morning will help thin them out. They are 

 excellent swimmers so it is not easy to drown them. Their 

 natural enemies are the most effectual means of keeping them in 

 check. Protect such. 



Three to eight young form a litter and several litters are born 

 annually. I have taken these Meadow-Mice containing young 

 nearly every month in the year. The young are born blind and 

 almost hairless. The nests are placed under logs, stumps, in 

 burrows, and sometimes in thick grass on the surface. 



One clear September morning I was camped by the side of 

 a brook in the mountains of San Diego County. The little stream 

 in some winter flood had cut a channel in the alluvial soil five 

 or six feet deep with nearly perpendicular banks and a dozen feet 

 wide. For a short distance below camp the bottom of the chan- 

 nel was moist and overgrown with watercress and a few round 

 tulles, through which the little stream meandered. In this vege- 

 tation some MeadowrMice were feeding. I laid on the edge of the 

 bank and watched them half an hour with the field glass, through 

 which they appeared nearly within reach of my hand. 



First some dry leaves were moved on a little slope at the 

 bottom of the opposite bank and the head and back of No. i ap- 

 peared. It was feeding on some small plants, but did not come 

 out openly. Presently No. 2 ran out of the tulles on the water- 

 cress and began eating it. It moved in a nervous, jerky way, 

 but did not appear shy. Soon No. 3 came but it was shyer and 

 did not stay long, biting off a small tulle about a foot and a half 

 long and dragging it into a thicker patch of tulles. It ran quick- 

 ly as if accustomed to pulling such loads. 



I did not see any of them sit up to eat, as many small mam- 

 mals do, nor did they use their fore feet to hold their food, using 

 only the mouth, apparently turning the leaves about with their 

 tongue. They did not take the larger sprays of watercress. 



