12 
THE CALIFORNIA GROUND SQUIRREL. 
WINTKU I'OISONIMG. 
Poisoniiii: (liirino: the rainy season with means thus far tested is 
dis}noj)ortionally expensive and should not be resorted to except in 
cases of extreme necessity. 
In the experiments carried on by the Biological Survey at ^lodesto, 
in Stanislaus County, Piper found that in November, after the winter 
rains had set in, the squirrels had ceased storing food and no longer 
carried the grain away in their cheek pouches, but hulled it on the spot 
and ate the kernel, casting off the outside and thus escaping the poi- 
FiG 4. — r.round squirrels killed by poisoned green barley heads at mouth of burrow. 
son. By scattering the grain widely the difficulty was in part over- 
come, for the squirrels rarely stopped to eat a single kernel, but first 
gathered a number and carried them to the mounds at the mouths of 
their burrows, and while so engaged were killed by the poison (fig. 4) . 
Nevertheless, at Modesto, during the wet season, the starch-barley 
poison proved far less reliable than during the dry season. This was 
due partly to the squirrel's change in habit — in ceasing to store food — 
and partly to the frequent rains, which washed off the poison. In 
other localities — notably about Fresno and Bakersfield — it was 
entirely successful in winter. 
