42 University of Califorma Publications in Zoology [ VoL. 17 
California cuckoo, whose food habits are largely unknown, probably 
displays this same habit of eating hairy caterpillars, as do other 
cuckoos. But this species is so rare in California that its work in 
comparison to that of the roadrunner must be slight. 
The stomachs of two roadrunners each contained a praying mantis, 
an insect seldom found in birds’ stomachs, perhaps because of its 
comparative rarity. An ant lion (Myrmelion sp.) had been eaten 
by one bird. A hairworm (?Gordius sp.) was found in one stomach, 
but as this stomach also contained grasshoppers it is probable that 
this parasitic worm originally may have been contained in one of 
these insects. 
VEGETABLE ANIMAL 
JAN. 9 
FEB. 2 
MARCH o 
APRIL 2 
MAY 14 
JUNE 8 
JULY 12 
AUG. 9 
SEPT. 6 
OcT. 6 
NOV. 9 
DEC. 6 
Text-Fig. B.—Diagram showing the average percentage of vegetable food 
(in white) and animal food (in black) consumed by the roadrunner in Cali- 
fornia during the various months of the year. Numbers at the right indicate 
the number of stomachs used in making the average. 
VARIATION OF FOOD ACCORDING TO TIME OF YEAR 
As is the case with most birds, the roadrunner is forced to vary 
its food from one part of the year to another. In the winter when 
insects become scarce vegetable food is resorted to. As can be seen 
by a study of text-fig. B, but small amounts of vegetable food are 
taken during the season when insects are abundant. A comparison 
of the actual numbers of insects taken by fifteen roadrunners during 
the summer months with those taken by the same number of birds 
during the winter months (table I) shows that during the summer 
season the roadrunner consumes on an average over twice as many 
insects as it does during the winter months. No noteworthy seasonal 
change in the kinds of insects taken is evidenced by the tabulation. 
