Display Diversity 
271 
is removed. Now there are two potential male 
combatants which are both “residents” and 
are initially at long range to each other. Ob- 
servations are made on the effect of distance 
upon the characteristics of the displays and 
on the effect of displays of one lizard on the 
subsequent behavior of the other animal with 
similar territorial status. 
In the field, lizards can be manipulated in 
several ways to obtain displays performed in 
different contexts. For recording male-female 
interaction, I use a camera with a strong 
telephoto lens (e.g. Nizo S80) and follow the 
male’s movements. As he patrols his terri- 
tory, he frequently will give nondirected dis- 
plays upon changing his perch site and will 
interact with resident females. I also may re- 
lease an intruder into a resident’s territory. 
To elicit aggressive displays, for instance, 
I use a male as large or larger than the 
territorial male under observation. The re- 
lease takes place out of sight of the resident 
male, allowing the intruder to recover from 
being handled before he encounters the resi- 
dent. The same method can be employed 
when releasing a female. Another procedure 
is to take a small aquarium containing a con- 
specific and place it within the territory of 
the observed lizard. In this experimental sit- 
uation, the resident male should be attracted 
to the confined conspecific. Knowing where 
the encounter will take place allows me to 
prepare the camera position. 
Cinema film and videotape are used to 
record display behavior. The television for- 
mat has several advantages over film. The 
video tape has 60 continuous minutes of re- 
cording capability, so all antecedent behavior 
is known and all displays are captured from 
the beginning. The 60 frame/sec resolution 
of the videotape also permits accurate 
analysis of extremely fast movements. Tape 
decks are available to permit frame-by-frame 
advancement of videotaped images. The main 
disadvantage is that the picture on a TV 
monitor is not as sharp as that of film. Try- 
ing to detect changes in body position from 
one frame to the next with a transparent 
grid overlay is almost impossible; the ref- 
erence lines of the overlay becomes lost in 
the sweep lines of the monitor. However, a 
digitizer (e.g., Numonics Model 234) can 
easily record the X-Y coordinates of the body 
parts by touching the monitor screen in 
successive frames with a hand-held stylus. 
These data can be manually recorded, or fed 
into a table top computer for processing. 
Lightweight Super 8 equipment is good 
for recording displays in the field. Filmed 
displays can be analyzed accurately by rela- 
tively low-cost techniques. For example, 
frame-by-frame analysis of Super 8 films is 
performed using a Kodak Ektagraphic 
MSF-8 projector, support box, mirror, clip- 
board, and clipboard guide (Fig. 2). Each 
sequentially viewed frame is projected off the 
mirror onto graph paper mounted on a clip- 
board. Head and dewlap positions are plotted 
for each frame, and the clipboard is progres- 
sively moved along a guide to receive each 
sequential frame of the movie. The rubber- 
backed clipboard guide is adjusted before 
each display so that the projected head move- 
ment of the lizard is parallel with the Y-axis 
of the graph paper. The movable clipboard 
guide also allows compensation during occa- 
sional display sequences when the camera 
moved slightly or the lizard’s perch moved 
(i.e., leaf or twig). 
Terminology 
A lizard display is typically composed of 
up and down head movements (usually aug- 
Figure 2. Equipment set up of frame-by-frame 
analysis technique. 
