Management studies must include an evaluation of factors that might 
be involved in a downward fluctuation following saturation. Will preven- 
tion of saturation prevent violent fluctuation, or will fluctuation come 
anyway? Will it be cyclic or irregular? Does disease become prevalent 
under conditions of abundance of the birds? Satisfactory answers to 
these questions are necessary for a knowledge of sound methods of increas-— 
ing the population of California valley quail. 
Food Supply Fluctuations 
Fluctuations in food supply caused by seasonal variation in pre- 
cipitation, both in quantity and in time of occurrence, may be of much 
importance to valley quail. Late fall rains followed by poor growing 
temperatures may cause a lack of green food, with the result that the 
birds come to the breeding season in a weakened condition. Succulent 
foods throughout the nesting period also are essential, for Sumner has 
shown that such foods, which Grinnell (5) believes are necessary to sur— 
vival of the chicks, are a satisfactory substitute for water. 
Drought 
Drought years are unfavorable to food conditions for valley quail 
end are characterized by reduced egg production (4, pp. 528-529). A. W. 
Anthony, quoted by Bendire (1), states that according to the testimony 
of Indians and Mexicans quail do not nest during drought, or do so only 
sparingly. Other writers make the same observations, and it is evident 
that there is a direct correletion between water supply and breeding. 
The remarkable quail increase in southeastern Santa Clara County during 
drought years, following removal of ground squirrels (see page 5), how- 
ever, would indicate that squirrel predation is a more important factor 
then drought. 
Natural Enemies 
Glading studied 90 nests on the San Joaquin Experimental Range. 
Of these, 17 were successful, and 13 were abandoned before laying. 
Nests were destroyed by ground squirrels (30), feral house cats (5), coy 
otes (5), spotted skunks (4), cattle (3), bobcats (2), California jays 
(2), a gray fox (1), ana undetermined predators (6); one also was de- 
stroyed by construction workers, and eggs were taken from another for ex-— 
perimental purposes. In this limited investigation it was found that 
ground squirrels destroyed as many nests as all other native predators combined. 
GROUND SQUIRRELS AS PREDATORS 
Nest Destruction 
Preliminary examination of various areas throughout the State con- 
vinced the writer that the major losses of valley quail occurred during 
