ANIMAL LIFE IN TEE YOSEMITE 



Meadow mice, particular^ those species which inhabit runways, are 

 given to extensive travel during the daytime. The runways are, in many 

 instances, nearly or completely covered by the adjacent grass, and would 

 seem to afford a more complete protection than is available to many of the 

 other small rodents. Nevertheless, meadow mice, more often than other 

 small rodents, fall victims to hawks; and their activity at dusk likewise 

 results in many of them being caught by owls. 



Fig. 17. Plan of the undergrouutl burrow system of a Mariposa Meadow Mouse. 

 Excavated on meadows 5^2 miles east of Coulterville, June 8, 191.5. Surface scale 

 about 1:25. 



On a meadow at the head of Bean Creek east of Coulterville a series 

 of runways and burrows of the Mariposa Meadow Mouse was opened up, 

 studied, and mapped by two of our party on June 8, 1915. (See figs. 17, 

 18.) The meadow was covered with a dense growth of rush, foxtail grass, 

 blue-eyed grass, soaproot, buttercup, wild celery, and other plants. The 

 fine black humus through which the tunnels were dug was damp and the 

 soil a few inches below the surface of the ground was saturated with water. 

 Some slight depressions in adjacent parts of the meadow still held standing 

 water. The part of the meadow where the tunnels were located was very 

 green; while on nearby higher and rockier parts the grass was already 

 dry and no evidences of meadow mice were to be found. 



Both surface runways and underground tunnels were found in this 

 colony, but only the tunnel system is shown on the accompanying diagram. 

 Some of the runways led into holes which looked like abandoned gopher' 

 holes, a fact which suggested that the meadow mice had possibly made use 

 of tunnels dug earlier by gophers. 



