UNITS OF CALL 
Marcellini 
290 
• t t t A,. ^ l.-i' i 
0-2 4 £ .6 1^ U 1.4 t£ IJ 2.0 2.2 2.4 
0 .2 .4 ,6 a U ) L2 1.4 [.6 1.6 2.0 2.2 2.4 2.6 28 M 5.2 
C 6- 
A I I I I t I i 
‘ >1 \ \ \ \ , , , 
0 .2 .4 £ .6 ID 1.2 L4 L6 1.6 20 
TIME IN SECONDS 
Figure 1. Sonagrams of the multiple chirp (MC) 
call of three adult male Hemidactylus freruitus 
recorded in Ciudad Vales, San Luis Potosi Mexico, 
March-May 1969. Fig. IB is a recording of a 
captive animal and is completely free of back- 
ground noise while Fig. lA and C are sonagrams 
of calls of free-living geckos and show attendant 
background noise between the chirps. 
counts were positively correlated with the 
number of active geckos. The churr call 
(Fig. 4) is an infrequently heard sound 
occurring only during aggressive encounters 
between males, and may function as a threat. 
The single chirp call is frequently heard, 
closely associated with distress, and may 
facilitate escape from predators (Fig. 4). 
Types of Call Produced 
Most calls mentioned in the early literature 
appear similar to the multiple chirp call of 
H. frenatus (Beebe, 1944; Schmidt and 
Inger, 1957; Brain, 1962; Petzold, 1965). 
The authors variously describe a series of 
chirps, barks, and clicks. Frankenberg 
(1974) and Haacke (1969), in their quanti- 
PERCENT OF TOTAL CALL 
Figure 2. Duration of chirps and pauses of the multiple chirp call of Hemidactylus frenatus expressed as a 
percent of total call. Horizontal lines show observed ranges; rectangles mark standard deviation with solid 
black indicating 96 percent confidence intervals for the means. Mean values are indicated by vertical lines, 
and the number of records for each chirp and pause is shown in parentheses. 
