292 
Marcellini 
B 
KHz 
IN SECONDS 
Figure 4. Sonagrams of churr calls (A) and single chirp calls (B) of Hemidactylus frenatus. 
human “predator” (Wever, et al., 1963; 
Bustard, 19676), I have observed that both 
H. frenatus and Gekko gecko use churrs 
during intraspecific aggressive interactions. 
Age and Sexvxil Factors 
The single chirp call has been reported to 
be produced by adults and juveniles of both 
sexes, but much more commonly by adults 
(Table 1). Churr calls have only been heard 
from adults. Although males are more prone 
to use this call, females can also produce 
them (Wever, et al., 1963; Bustard, 19676; 
personal observation). Reports of multiple 
chirp calls in the literature have mentioned 
only adult male vocalizations (Haacke, 1969; 
Frankenberg, 1974). In H. frenatus, I have 
observed both adult male and female geckos 
making this call; it is produced more fre- 
quently by males. In summary, all three calls 
