Iguana Specialist Group newsletter (ISG newsletter)
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Iguana Specialist Group

Volume 7 * Number 1 * Spring 2004

international Iguana Foundation Announces 2004 Grants * The Board
of Directors of the International Iguana Foundation (IIF) held their annual
meeting at the Miami Metrozoo in Florida on 3 April 2004. The Board evalu-
ated a total of seven proposals and awarded grants totaling $48,550 for the
following five projects:

1) Establishing a second subpopulation of released Grand Cayman blue iguanas,
Cyclura lewisi. Fred Burton, Blue Iguana Recovery Program. $11,000.

2) Conservation ofthe critically endangered Jamaican iguana, Cydura collei. Peter
Vogel and Byron Wilson, Jamaican Iguana Research and Conservation Group.

3) Maintaining and optimizing the headstart release program for the Anegada
Island iguana, Cyclura pinguis. Glenn Gerber (San Diego Zoo) and Kelly Bra-
dley (Dallas Zoo and University of Texas). $11,250.

4) Translocation, population surveys, and habitat restoration for the Bahamian
iguanas, Cyclura r. rileyi and Cyclura r. cristata. William Hayes, Loma Linda
University. $7,500.

5) Conservation biology and management of the Saint Lucian iguana, Iguana
iguana. Matt Morton (Durrell Wildlife Conservation Trust) and Karen Gra-
ham (Sedgwick County Zoo). $7,500.

Rick Hudson, IIF Program Officer
Fort Worth Zoo

O obituary * The herpetology and veterinary
staff of the Gladys Porter Zoo sadly report the
passing of the longest living member of the genus Cy-
clura on record.
At an estimated age of 69 years, "Godzilla," a
male Grand Cayman blue iguana, died on May26, 2004
of apparent chronic hepatic insufficiency. He was ill for
about two weeks prior to his death, although at his ad-
vanced age, Godzilla required extraordinary maintenance
for the seven years he resided at the Zoo. Totally blind
in one eye and almost blind in the other, this animal
routinely brought out the "hero" in the Gladys Porter
Zoo's veterinarians.
Captured as a full-grown adult on Grand Cay-
man in 1950 by naturalist Ira Thompson, Godzilla
weighed over 15 pounds and was estimated to be at least
15 years of age at his time of capture. He was imported
to the U.S. in 1985 by Ramon Noegel of Life Fellow-
ship Bird Sanctuary, and was placed on loan to the
Gladys Porter Zoo in 1997.
Though gaunt and aged in appearance, Godzilla
retained the characteristics of a territorial, dominant
lewisi up until the time of his final illness. As a poten-
tial founder for the critically endangered population of
Grand Cayman iguanas, many creative schemes were
attempted to assist him in mating with a much more
nimble female. He was a favorite of the Zoo's keeper
staff and volunteers; he will truly be missed.
Colette Adams
Gladys Porter Zoo

C ayman Brac Land Preservation * The
International Reptile Conservation Foundation
(IRCF), a 501 c(3) non-profit corporation directed by
John and Sandy Binns, has donated property on Cay-
man Brac to the National Trust for the Cayman Is-
lands be used as a nature reserve. Twelve mile long
Cayman Brac is a tilted plateau starting at sea-level
and rising gradually to 150 ft high cliffs at its east end.
The donated property is located in the western, lower
lying reaches of an area at the top of the plateau known
as the Bluff. It includes two deep rifts in the rocky
landscape, which reach down past the underlying
groundwater to create two narrow, linear waterways,
locally known as the Splits. With surface water other-
wise scarce on Cayman Brac, the Splits supports di-
verse semi-deciduous dry forest and a large concentra-
tion of wildlife, including an endemic subspecies of
racer (Alsophis cantherigerus), an endemic subspecies
of Cayman ground boa (Tropidophis caymanensis), two
gecko species (Aristelligerpraesignis and Sphaerodactylus
argivus), a galliwasp skink (Celestus maculatus), and an
endemic varietyof the Cuban anole (Anolissagrei). The
area was also once home to the endangered Sister Isles
rock iguana (Cyclura nubila caymanensis) and could
potentially be used as a relocation site for the species.
The Splits originally belonged to respected pio-
neer doctor, the late Dr. Hermann, who in turn be-
queathed it to his four daughters Barbara H. Wolf,
Louise H. Trost, Carol H. Shepard, and Shirley H.
Andrews. Aware of their father's love for its wildlife
and natural beauty, they felt it was appropriate that
the property be donated through the
IRCF, with the help of Fred Burton and
Mat Cottam, to the National Trust as a
protected nature reserve.

John Binns
Ind. Reptile Conservation Foundation

Godzilla, at least 69 years old, died in May 2004. Photo by John Binns.


Biology and Conservation

"This valuable reference pulls material from loved by professional
scattered sources into one volume. It provides herpetologists and
an excellent review of iguana ecology, behavior, hobbyists alike.
evolution, and genetic diversity."--Bill Cooper, Allison C. Alberts is
Indiana University-Purdue University Head of Applied
Conservation at the
"In a most graceful manner, this book combines ZoologicaL Society of San

the most current information on iguanas from
several typically disparate fields of study. This volume
addresses the need for current information by conservation
biologists and nature enthusiasts with an interest in
iguanas."-Robert Powell, Avila University, Kansas City

In what is certain to be the key reference on iguanas for
years to come, some of the world's leading experts offer a
clear and accessible account of the latest research on the
evolution, behavioral ecology, and conservation of these
highly visible and increasingly endangered creatures, much

Diego and the editor of
West Indian Iguanas:
Status Survey and Conservation Action Plan (2000). Ronald L. Carter is
Professor of Biology at Loma Linda University. William K. Hayes is
Associate Professor of Biology at Loma Linda University. Emilia P.
Martins is Associate Professor of Biology and Director of the Center for
the Intcgrative Study of Animal BIhavioi at Indiana University,

372 pages, 7 x 10", 6 b/w photographs, 51 line illustrations, 8 maps,
57 tables
$65_00 cloth 0-520-23854-0

For a complete Table of Contents go to: h rplga.ucpnress.edulalberts

Please send me Iguanas


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St. Lucia iguana (Iguana iguana)

The St Lucia Iguana Project began in December 2001
as a collaboration between Durrell Wildlife (DW) and
the St. Lucia Forestry Department (SLFD), in response
to a perceived decline in the distribution and numbers
of the iguana on St. Lucia. Ongoing genetic work sug-
gests that this population may be distinct from all other
green iguana populations so far analyzed. Since 2002,
Sedgwick County Zoo (SCZ) has also been actively in-
volved in supporting the project through logistical sup-
port and assistance in the field.
Iguanas have proven to be very difficult to locate
in the densely vegetated habitats of St. Lucia, even in
areas known to harbor them. In upcoming months we
will evaluate the feasibility of flashlightsurveys bynight
as means of locating both adult and dispersing hatchling
iguanas. Long-term residents of regions throughout St.
Lucia will be surveyed more systematically regarding
iguana sightings, as well as a perceived absence of igua-
nas. Together with satellite imagery to be obtained from
the government, these surveys will be utilized to inves-
tigate habitat suitability across the island.
In part due to the difficulty of locating iguanas
in non-nesting habitat, much of the emphasis on data
collection during nesting and hatching has occurred at

Adult male (left) and emerging hatchling St. Lucia iguana. Photos

the two known nesting beaches, Louvet and Grand
Anse. In 2003, SLFD assisted in collecting data from
these beaches. Due to considerable human resource
constraints, most data collection was concentrated at
Louvet beach. In 2004, DW funded travel and subsis-
tence for four volunteers to work in teams of two at
each beach location for the duration of the nesting and
hatching seasons. These volunteers receive valuable field
support by local individuals, contracted by SLFD and
DW The aim is to use the data gathered to develop an
appropriate technique that will be practical for long-
term population monitoring.
Nesting activity on beaches. In early March 2003,
SLFD began beach searches for indices of nesting ac-
tivity (tail drags, disinterred eggshells, nest holes, and
sightings of female iguanas) but nesting had clearly al-
ready begun by that time. In 2004, we have confirmed
that nesting activity began in the first week of Febru-
ary. The 2003 data on nesting activity suggest a peak
of activity in mid April, but a more complete picture
will be obtained after 2004 monitoring is complete.
We restricted our searches to beaches, as these
are the only sites where tail drags were easily visible.
Also, we have no reports of nesting at non-beach sites
(although two reports of hatchlings away from beach
sites have been logged, it is unclear whether these rep-
resent nest sites or dispersing juveniles). We only found
signs of nesting at two relatively remote beaches on the
northeast coast, despite searches around the island.
Many of the other beaches surveyed lacked the combi-
nation of thick beachside vegetation (primarily
Coccoloba uvifera and Tabebuia heterophylla) and open
sandy gaps that characterize the nest sites at Louvet and
Grand Anse. Human (and associated domestic ani-
mal) usage of many of these other beaches (including
illegal sand mining, tourist visitation, and fishing) ap-
peared more intensive than at the
two confirmed nesting beaches.
In 2004, we excavated eggs
from six newly dug nests. Nest
burrows and egg chambers were
mapped up to the point at which
the egg clutch was discovered.
Mean clutch size was 22 eggs
(range 16-25, sd -+ 3.39) and
mean depth of the egg chamber
below the surface was 0.45 m
by Matthew Morton. (range 0.30-0.65, sd t 0.11).

Data loggers to record temperature were installed in
three active egg chambers plus a fourth chamber con-
taining the shells of 19 apparently hatched eggs from a
previous season. The latter location was selected over
active nest sites because it was the site of many
hatchlings with minor deformities (small tail kinks and
skin lesions) in 2003 and temperature has been sug-
gested as a potential cause.

Hatching. Nesting and hatching seasons are extensive
and very nearly overlap. The last observed nest dig-
ging of 2003 was in the first week of May; the first
hatchlings were seen the following week. From the
last week in May 2003, and also from the first week in
July in 2002, nine and six nest aggregations, respec-
tively, were fenced with polythene sheeting and checked
every 20-30 minutes throughout the day until 90 days
after the last sighting of an adult female at the beach
(corresponding to the reported incubation reported for
Iguana iguana). These nine fenced areas appear to rep-
resent the vast majority of nests on the Louvet beach,
although some hatchlings are known to have emerged
outside of these fences and were not counted.
In 2003 we counted 1,308 hatchlings. Mean
SVL: 76 mm (60-94, n = 233); Tail length: 193 mm
(131-212, n =233); body weight 14 g (5-19, n = 232 -
the 5g individual was an outlier, clearly very dehy-
drated). The sex ratio was 1.00:0.83 F:M (n = 517).
Based on 'pulses' ofhatchling numbers (bearing in mind
possible multiple clutch emergences, egg mortality, etc)
we estimated clutch size as 17-20. From the hatchling
counts, we estimated total hatchlings for the full sea-
son to be 1,734. Using our 2004 estimate of mean
clutch size = 22, this gives an estimate of 79 success-
fully reproducing females at this site.
In 2004 we will attempt a more complete count
of hatchlings at both Louvet and Grand Anse beaches
and use the estimated number of females derived from
this to calibrate the indices of nesting activity obtained
during the nesting period. During hatching, we will
also collect blood samples for health screens, and tis-
sue samples for DNA analysis in order to gain insight
into the level of genetic diversity that still exists in this
seemingly small population, the degree of maternal fi-
delity to the nests where they were born, and the de-
gree of gene flow between the two nesting beaches.

Nesting migration, juvenile dispersal, and mortality.
In 2004 we captured a small sample (n = 6) of females
at nests (both ore- and post- ee lavine) and fitted them

Fenced nesting area, Louvet beach. Photo by Matthew Morton.

with radiotransmitters (ca. 15g each) on belts around
their waists. We aim to estimate migration distances
by following these females as they return to their nor-
mal home ranges. Later in 2004 we also plan to radiotag
a small sample ofhatchlings to study their movements
in and around the nesting areas as they disperse. This
work will hopefully also provide data on predation away
from nests themselves and provide information on the
confounding effects of emigration and survivorship.

Predation. As indicated by stomach content examina-
tion, mongooses are predating emerging hatchlings in
the immediate vicinity of nests. Disturbingly, adult
iguana remains were also found in the gut of one mon-
goose in 2004, indicating that mongooses are either
eating adult iguana carrion, or possibly preying on live
adult iguanas.
Cats appear to be a new threat on Louvet beach.
In 2002 no cats were seen by researchers or project as-
sistants, and long-time resident of the Louvet estate,
Seko (Anthony Johnny), feels confident that cats have
not previously occurred on the beach, at least in recent
years. Throughout most of the 2003 hatching season,
two cats were seen at the nest sites after dark. As with
the mongooses, they were clearly targeting the nests; a
number of kills were confirmed by uneaten tails and
mutilated bodies of post emergent hatchlings, predated
overnight (mongooses are diurnal). Assuming these ani-
mals have only arrived in this area in the last year, it

1 I


may be that no cat population is
yet established here (Louvet
beach is 2-3km from the nearest
human community). Unfortu-
nately, aggressive attempts to live
trap these predators were unsuc- M u
cessful in 2003. -
Dogs do not appear to
prey on hatchling iguanas but are
a serious threat to adults. Dur- * " I"
ing March-May 2003 we found
six remains of dead adult igua-
nas; at least three were at or near
nests. Cause of death was not
immediately apparent but dogs
seem the only plausible culprits.
At Louvet in particular, one dog
was believed to be targeting the
nest area; SLFD have sought help
from the St. Lucia police to shoot
Louvet Estate entrant
the animal. This year we found Antoine (SLFD), and
clear evidence ofegg predation by (local residents contr
mongooses at nests on Louvet Photo by Matthew M
beach (footprints leading into
opened nest tunnels, eggshells strewn around the en-
trance). Native predators include birds, primarily
American kestrels (Falco sparverius), broad-winged
hawks (Buteo platypterus) and herons (little blue her-
ons Egretta carerulea, and green herons Butorides
virescens; the yellow-crowned night heron Nyctanassa
violacea is also present, although it hasnot been di-
rectly observed predating hatchlings). Boas (Boa con-
strictor) and fer-de-lance (Bothrops caribbaeus) are po-
tential predators ofhatchlings - both are present around
the nest sites, though we have no observations of pre-
dation. There was also a single sighting of a boa (Boa
constrictor) caught in the process of swallowing an adult
iguana. (In 2004, three adult boas, two large enough
to take adult iguanas, were seen in the 500m strip of
sea grape bordering the nest areas at Louvet).

Site Management. Thus far, the privately-owned
Louvet Estate appears to have highest density of igua-
nas remaining on St. Lucia and the landowner seems
enthusiastic about a voluntary wildlife management
plan. Signage at the estate, and controlling access to
critical nesting areas with a road chain, were funded by
the International Iguana Foundation in 2003, have been
the first concrete step in this direction. Defining

ce, wil

patrol routes for SLFD to follow
will be completed in 2004. We
will also attempt to draft a more
full management plan for this large
estate (apparently > 500 acres) in
2004-5, incorporating proposed
work on designation of protected
areas along the northeast coast.

U#Wy Community outreach. We con-
tinue to work with the SLFD Edu-
cation Unit to develop a proposal
for funding an education program.
Since mid 2003, our focus has
changed from an island-wide pro-
gram to one centered on key com-
munities in iguana habitat, with
an emphasis on a community-led
Our plan is based on a trial
k and Sampson, education program developed and
k and Sampson, li1ered by
to install the sign). delivered by SLFD in early 2003,
which convened panels of teach-
ers and parents to develop curricu-
lar activities for their community's children, thus en-
gaging and sensitizing the adult population at the same
time as the schoolchildren, rather than waiting for key
messages to trickle-down from children to adults.
In addition, we are investigating the feasibility
of small-scale eco-tourism initiatives on the northeast
coast. Our approach is to address the apparently acute
anthropogenic threats facing iguanas in these areas by
'investing' local people in their conservation, ideally pro-
viding some members of the community with employ-
ment. The local model for this has been the successful
community-led Turtle Watch project at Desbarra, cur-
rently employing about 12 people, having brought in
over EC$ 6,000 in 2003 alone and responsible for a
decline in leatherback turtle poaching on Grand Anse
beach and ongoing data collection on nesting.

c" Matthew Morton
Durrell Wildlife Conservation Trust
Karen Graham
Sedgwick County Zoo

Cuban iguana (Cyclura nubila nubila)

Burrows and Morphology of Cuban Iguanas (Cyclura
nubila) Inhabiting Cruz del Padre Cays, Sabana-
Camagiiey Archipelago, North of Matanzas.
Translated/edited from Spanish By Jean-Pierre
Montagne and ISG newsletter editors (San Diego Zoo).
Some ecological aspects related to the burrows and
morphology of the Cuban iguana Cyclura nubila nubila
were studied on Cruz del Padre Cay, to the north of
the Cardenas, Matanzas Province. For the Cuban
iguana several observations indicate that burrows are
the limiting key resource affecting population size, in
the form of refuges from predators, climatic stress, and
sites for oviposition (Berovides, in press). It is known
that the availability of refuges can regulate the popula-
tions of some species of birds, freshwater fishes, am-
phibians, snails and other river invertebrates (Beck,
1955). Anecdotal references (Carey, 1975; Iverson,
1979) indicate the rapidity that areas containing trash
piles, rocks, tree trunks, and other hiding places are
colonized by juvenile iguanas, suggesting a deficit of
this resource in the environment.
Diverse researchers have studied the Cuban
iguana, but only a few make explicit references to their
burrows (Sutcliffe, 1952; Hardy, 1956; Perera, 1985;
Cubillas and Berovides, 1991; Gonzilez et. al., 2001)
which can be in rocks, in tree cavities or excavated in
the sand. If burrows act as limiting resources for Cu-
ban iguana populations, then the study of their char-
acteristics, abundance, and potential for manipulation
may have special importance for the long term effec-
tive conservation of this species, considered threatened
with extinction and categorized by IUCN as vulner-
able (Berovides et. al., 1996).
Our objectives were (1) to validate use of bur-
row abundance as an indirect measure of iguana abun-
dance, as described in Cubillas and Berovides (1991);
(2) to compare several measurements between occu-
pied and unoccupied (abandoned) burrows, and (3) to
determine whether or not a correlation exists between
burrow characteristics and the morphological measure-
ments of animals using it. All of our work was con-
ducted with burrows excavated in the sand.

Materials and Methods. The study was completed in
January 1999, under normal climatic conditions. The
location of the study was Cruz del Padre Cay, north of

Matanzas Province. This cay is characterized mainly
by sandy ground and shrub vegetation (coastal xeric
scrub) and the remainder is mangrove. Iguana bur-
rows were studied in the area of Los Angulos beach.
Using a compass and tape measure, 19 sand
burrows were measured for orientation, cover, entrance
width (cm), overall entrance height (cm) [measured
from ground surface to the base of the entrance], en-
trance height (cm) [measured from the inner edge (ceil-
ing) of the entrance to the entrance base], thickness of
the entrance (cm) [difference between the two inner
measurements], and distances between burrows (m).
Whether the burrow was occupied or not was also re-
corded. The plant cover surrounding each burrow was
determined by method of line intercept (Franco et. al.,
1992) with the burrow in the center and two 5 cm
long perpendicular lines at intervals of Im. The amount
of contact that shrub vegetation (approximately 1m in
height) made with the line intercept was recorded to
give a measure of the number of shrubs/m along the
line intercept.
The distances between burrows (N= 16) allowed
us to calculate burrow density (D,) using the formula
D, = 1/2.78 d2 x 10,000 (Cottam and Curts, 1956)
and thus to indirectly estimate the density of iguanas
(D2) as D2 = D, x O (Cubillas and Berovides, 1991),
where O = percentage of occupation. The density of
burrows estimated by this method was compared with
that obtained in the study of a 0.56ha plot, where 20
burrows were detected.
All these measurements were made in an area
of approximately 560m2 (80x70m), in the northwest
part of the sandy zone of the cay, about 22.4 m from
the Los Angulos channel. On the opposite end of the
sandy strip seven burrows were measured and opened,
all of which were inhabited by adult females. For the
burrows, the orientation, entrance width and height
(cm) (as in the previous case), as well as length and
depth (m), were measured. In the captured animals,
the following variables were measured: weight (g) and
15 morphological variables, including the lengths (cm)
of tail, head, femur, tibia, humerus, radius, fourth toe-
nail on forefoot and hindfoot, fourth toe including nail
on forefoot and hindfoot, overall length and snout-
vent length, in addition to head width and the width
of the left hindfoot excluding the fifth toe.
Means of the measured variables in occupied
and unoccupied burrows were compared by T-tests.

Distance /
S Burrows
Replicates 1 16
Average distances (mean � S.D.) - 10.2 � 8.3
Burrows / hectare 35.7 34.2
Iguana / hectare 16.1 15.3
Table 1. Density estimates ofiguanas based on two methods on Cruz del Padre cay,
Occupied burrows Unoccupied burrows
(n -9) (n- 10)
Variables mean � S.D. mean � S.D.
Orientation (degrees) 190.3 � 112.6 188.8 � 116.1
Cover 134.0 �35.4 159.0 � 14.2
Entrance width (cm) 14.8 � 4.8 11.7 � 3.4
Entrance height (cm) 6.4 � 3.0 5.1 �1.9
Entrance thickness (cm) 11. 5.3 7.7 � 5.4
Burrow distance (m) 12.3 � 10.0 8.2 � 6.2
Table 2. Comparison ofsix variables between burrows occupied and unoccupied
by iguanas on Cruz del Padre cay. Cover denotes the average contact ofshrubs/m.

Variables mean � S.D.
Orientation (degrees) 105.7 � 54.9
Entrance width (cm) 17.6 � 4.7
Entrance height (cm) 5.9 � 1.7
Entrance thickness (cm) 10.1 � 4.4
Length (m) 2.9 �0.8
Depth (m) 52.6 � 14.1
Table3. Mean and standard deviations (S.D.) fr six variables
of seven iguana burrows occupied by females on Cruz del Padre cay.

Variables mean � S.D. r
Weight 884.28 �278.31 0.531
Total length 60.48 � 8.03 0.106
Snout-vent length 23.32 � 4.66 0.222
Tail length 37.15 � 9.22 0.021
Head length 4.65 � 0.71 0.124
Head width 3.45 � 0.96 0.383
Femur length 5.66 � 0.79 0.428
Tibia length 5.98 � 0.41 0.045
Humerus length 4.54 � 0.54 0.333
Radius length 4.31 � 0.50 0.484
Nail lenght (hindfoot) 0.97 � 0.09 0.787
Nail length (forefoot) 0.79 � 0.13 0.364
Fourth toe length (hindfoot) 4.63 � 0.32 0.705
Fourth toe length (forefoot) 2.94 � 0.36 0.320
Hindfoot length with nail 8.07 � 0.54 0.341
Foot width 2.02 � 0.22 0.420
Table 4. Mean and standard deviations (S.D.) of15 morphological
variables (cm) and weight (g), and their correlations with burrow
entrance height in 7 individual female iguanas on Cruz del Padre cay.

Sablte . Values ofload factors in an analysis of main components, for six
morphological variables and burrow entrance height for iguanas on Cruz del Padre ca

Pairwise correlations were determined for vari-
ous measurements of the open burrows that con-
tained iguanas, as well as between the morpho-
logical measurements and weights from the cap-
tured individuals and these same burrow mea-
surements in order to extract the relevant vari-
ables of both groups of measurements for princi-
pal components analysis (PCA).

Results and Discussion. Table 1 presents the es-
timates of burrow density based on the distances
between burrows (N=16 measured) and its vali-
dation by direct counting. Both methods coin-
cide given expected errors of estimation, and give
density estimates of iguanas that are also similar,
based on 45% occupation, determined at the
same study site. These results reconfirm the util-
ity of the method of indirect estimation of iguana
density by the measurement of the distances be-
tween burrows, results similar to those obtained
by Gonzalez et. al. (2001) for the population of
iguanas of Cayo Rosario. Nevertheless, our esti-
mate of the percentage of burrow occupation
(45%) was lower than the esitmate in that study
(50%); than the one of Cubillas and Berovides
(1991, 60%), and in others not published (63%
Cayo Juan Garcfa, Cayos de San Felipe; 66%
Cayo Obispo, Jardines del Rey), which indicates
a possible recent extraction of mosdy male indi-
viduals. When 11 burrows were opened (seven
of which were part of the present study), only a
single male was found.
Differences between occupied and unoc-
cupied (abandoned) burrows in cover, width and
entrance height, entrance thickness and distances
between burrows were not statistically significant,
either because no real differences exist or because
of small sample size (Table 2). We believe the
latter is more likely due to the fact that the ob-
served differences are in the expected direction,
given what is known about the ecology of igua-
nas in relation to their burrows. The observa-
tion that inhabited burrows tend to have less cover
(Julio To Ramos, personal communication),
agrees with our results. Also it has been observed
that the juveniles tend to utilize several burrows
that are abandoned quickly (Iverson, 1979). In
our study, all the dimensions of the abandoned


Variables Cp1 Cp2
Burrow height 0.681 0.006
Snout-vent length 0.599 0.747
Weight 0.879 0.335
Head width 0.693 0.523
Femur length 0.741 0.392
Humerus length 0.867 0.255
Hindfoot nail length 0.923 0.139
Eigemvalue 4.233 1.184
__% _60.480 16.920

burrows were smaller than the occupied ones. In addi-
tion, abandoned burrows are closer on average.
Table 3 presents the means and the standard
deviations of six variables measured in seven burrows
of iguanas inhabited by females. Simple pairwise lin-
ear correlations between these variables revealed that
entrance height was the variable with the highest cor-
relation coefficients: with direction, 0.417; with thick-
ness, 0.347; with width 0.369; with length, 0.425 and
with depth, 0.335. Therefore, the entrance height was
the burrow variable selected for the PCA.
Burrow height was then correlated with weight
and morphological measurements (Table 4). Although
the only statistically significant correlation was between
burrow height and hindfoot nail length (r=0.787; p <
0.05), many other variables had (r) values between 0.30
and 0.60, especially the measurements of the lower
extremities. Weight, head width, snout-vent length,
and measurements representative of the anterior (hu-
merus length) and posterior (femur length and hindfoot
nail length) extremities were then used for PCA (Table
5). The two first components explained more than
70% of the total variation, and component I was posi-
tively associated with burrow height, weight, and all
the morphological measurements, but especially femur
length, humerus length, and hindfoot nail length, all
of which are related to burrow excavation.
These results suggest that burrow entrance
height can be a good indirect indicator of the size of
the animal, and that it may be possible to use average
values of burrow height to indicate the size structure of
the study population.

Beck, M.W 1995. Size-specific shelter limitation in stone
crah. Ecology 76:968-980.
Berovides (in press). Factores reguladores comunes en tres
species de Vertebrados Cubanos: jutfa conga (Capronmy
pilorides), cotorra (Amazona leucocephala) e Iguana (Cyclura
nubila). Biologia.
Berovides, V., P Rodriguez, and S. Cubillas. 1996. Cyclura
nubila nubila. Taller para la conservaci6n, anAlisis y manejo
planificado de una Selecci6n de Especies Cubanas. SSC-
UICN, La Habana, pp 93-96.
Carey, WM. 1975. The rock iguana, Cyclura pinguis on
Anegada, British Virgin Islands. Bull. Florida State Mus.
Biol. Sci. 19:189-233.
Cottam, G. and J.T. Curtis. 1956. The use of distance
measures in phytosociological sampling. Ecology 37:451-
Cubillas, S. and V Berovides. 1991. Caracteristicas de los
refugios de la iguana de Cuba Cyclura nubila. Biologfa 1:85-
Franco, J., G. de la Cruz, and A. Cruz. 1985. Manual de
Ecologfa. Ed. Trillas, Mexico, 163pp.
Gonzilez, A., V. Berovides, and M.A. Castafieira. 2001.
Morfometria, abundancia y alimentaci6n de la iguana
cubana Cyclura nubila nubila en Cayo del Rosario. Biologfa
Hardy, J.D. 1956. Note on the Cuban iguana.
Herpetologica 12:323-324.
Iverson,J.B. 1979. Behaviorand ecology of the rockiguana,
Cyclura carinata. Bull. Florida State Mus. Biol. Sci. 24:175-
Perera, A. 1985. Datos sobre la abundancia y actividad de
Cyclura nubila nubila en los alrededores de Cayo Largo del
Sur. Poeyana 288:1-17.
Sutcliffe, R. 1952. Result of the Catherwood-Chaplin West
Indian expedition, 1948. Part VI. Amphibia and reptilia.
Notulae Naturae: Acad. Natur. Sci. Philadelphia 243:1-8.

ew Luis D. Avila Cabadilla
Minister of Science, Matanzas
Vicente Berovides Alvarez
University of Havana

Observations on the Population of Cyclura nubila nubila
Inhabiting the Mount Cabaniguin Wildlife Refuge, Las
Tunas, Cuba.
Translated/edited fom Spanish by Jean-Pierre Montagne
and ISG newsletter editions (San Diego Zoo).

The Mount Cabaniguin wildlife refuge is one of the
few protected areas of Cuba that is home to a popula-
tion of Cuban iguana (Cyclura nubila nubila) that lives
exclusively in mangroves and coexists with the Ameri-
can crocodile (Crocodylus acutus). Here we present our
observations on the ecology of this population.
Habitat use. Generally, iguanas at this site inhabit red
mangroves (Rhizophora mangle), almost always on the
shore of the estuary, which allows them to bask in the
sun at dawn and dusk. Other than in nesting sites,
which are the only places unaffected by the tide, we
rarely found iguanas on the ground, suggesting that
they are arboreal at all ages. At La Salina, a high site
with a strip of cacti, iguanas always construct their
burrows beside or within cacti; the site is also excellent
for nest construction. Crocodiles nest in the area each
year prior to the iguanas, which prepares the soil for
iguana nesting. The reason we did not find iguanas in
rocky crevices is because the region is marshy and the
tide floods the entire mangrove area. The hollows of
trees, generally made by woodpeckers, can only lodge
small animals, so we rarely found adults in them ei-
ther. The arboreal refuges used by iguanas are located
in those mangroves that have been divided by
the wind and hollowed out by the action of the
water. The heavy branches help the iguanas to
camouflage themselves and at the same time
serve as perches for sleeping. By 1600, we find
iguanas at the place they will spend the night
or close to it (principally in the cold season).
Night perches vary according to the time and
to interference from conspecifics. If they are in
burrows, iguanas usually become active again
by 0900.
Adults are territorial; especially males.
Females are a bit more tolerant, and will occa-
sionally allow other females near their perches.
During the first year of life, iguanas can be gre-
garious. In October of 1995, while looking for
unemerged crocodile nests in Jobabito we found

an iguana nest out of which nine hatchlings emerged.
We collected two individuals that measured 31.0 and
31.4 cm in overall length. In November of 2001, we
saw something similar, but this time within a burrow
left by a green woodpecker in a dry and fallen red man-
grove. Four hatchlings emerged running at full speed
and we caught one that measured 29.6 cm in overall
length and weighed 49.7 g.
Feeding. We know that wild iguanas feed on fruits
and flowers of black mangrove (Avicennia nitida), leaves
of red mangrove, verdolaga de playa (Portulaca olivacea),
small corpses of birds, fish, and crabs (Aratus and Uca),
and fruits and leaves of Opuntia and Harrisia, Talassia,
and grasses. They appear to actively select their pre-
ferred foods from those available. We have been amused
to see two or more animals eating on the dune - when
one finds a piece of its favorite food and another one
approaches, it stampedes away to avoid having its food
snatched away from it. Flowers are among the favor-
ites, including those of black mangrove and verdolaga
de playa.
Nesting. Iguanas begin laying at the end of crocodile
hatching, during the first week of July. Peak laying
generally occurs in the middle of the month, at which
time females move toward the nest building areas:
Jobabito, Salina, Ojo de Agua, Soloburen, and Jijira,
although we have also found nests in Tfo Lindo and
the neighboring areas of the Biological Station. The
nests consist of a tunnel and an incubation chamber.

Flowering Oputia. Photo by JP Montagne.

The tunnel can have more than one entrance, and the
iguanas do not necessarily use the initial entrance that
was made when they began constructing the nest. The
entrances are always covered, but sometimes
characteristics of the terrain provide indirect in-
formation on nest structure. The length of the
tunnels we have observed are between 35 and
151 cm. The size of the chamber depends on
the size of the female and the depth of the area
where the nest is excavated. Based on our ob-
servations to date, the depth to the last egg has
been between 17 and 29 cm. As a rule the nests
are constructed near the roots of herbaceous
plants. When the iguanas are within the nest
they cover the entrance, the chamber is only
found open when work is being initiated on it.
There is evidence that the chosen nest-
ing site is reused. In each nest we located we
found the remains of hatched eggs from the
previous year, indicating that suitable places for
nesting are returned to year after year. As with the
crocodile, the lack of suitable nest sites is a limiting
factor affecting reproduction in this species. This may
explain why females are forced to migrate for laying,
giving rise to the gregarious behavior observed during
nesting. We rarely found isolated nests. Following a
similar pattern to the crocodiles, iguana nests are
aligned linearly toward the edges of the area and form
triangles when they are more to the center (the nests
occupying the vertices of the triangles).
Clutch size observed to date is between three
and thirteen eggs. The size and weight of each egg
becomes more homogenous as the clutch size is greater.
In small clutches eggs may be notable in both their
length and width. The weight of eggs is between 40
and 125 grams. Egg fertility is surprisingly high; we
have not found infertile eggs in sampled nests. Cases
of hatching failure (no eclosion) have not been due to
embryonic mortality but instead to extreme humidity,
or flooding of the nest chamber. Hatchling size is be-
tween 26.4 and 33.6 cm overall length.
Response to climatic changes. Iguanas change their
behavior in response to climatic changes, particularly
as a result of low temperatures, more dramatically if
accompanied by rains. Normally they begin activity
at 0900 but when it is cold and wet they are able to

stay in their refuges or on their perches for days with-
out moving. Adults are less affected than young. i
Perches are generally situated where the sun warms them

Cuban iguana at Guantdnamo Bay. Photo by Allison Alberts.

up in the morning. We have seen hatchlings remain
for four days in refuges without leaving at ambient tem-
peratures of 20"C with cold winds and rain (October
28 to November 2).
During cold days in January, (19�C), large ani-
mals that could not find refuges in tree hollows, were
located by 1600 on perches near the border of the es-
tuary, where they could receive warmth from the sea
during the night, as well as the first rays of morning
sunshine. When sleeping outdoors, the iguanas select
places that are almost always heavy branches dense with
leaves, usually hiding their heads in the foliage. We
located 16 iguanas from Cuatro Bocas to the Biologi-
cal Station, all facing east (5 females and 11 males) and
verified that they did not move during the night.
Behavior of hatchlings and yearlings. After freeing
themselves from their eggs, recent hatchlings remain
for several hours within the nest chamber, then initiate
excavation towards the outside; excavations are made
diagonally. When arriving at the surface, they emerge
head first and remain calm for several minutes. When
they leave the nest, they run at full speed looking for
protection among the plants. The remaining iguanas
use the tunnels opened by the first to leave the nest.
During the first six months, hatchlings may remain in
groups, sharing the refuge or tree where they live, but

after this they begin to disperse. Once they obtain a
suitable site (hollow in a tree or accumulation of weeds
in a high site), they settle into a more stable home range.
Young iguanas prefer to eat the tender parts of
red mangrove, flowers and sprouts of black mangrove,
verdolaga, buds of grasses that grow in dunes in spring,
and soft foods they can tear or cut easily. As the tem-
perature increases during the day, their appetites in-
crease. During November, the iguanas born during
the past year as well as the young of the current year
begin to shed.
At one year of age, sexual characteristics begin
to manifest themselves. In males, the dorsal spines be-
come more prominent, the head begins to appear more
robust, the scales of the jaw stand out, and the femoral
pores become more obvious. At this age they begin to
display characteristic head movements more frequently
and vigorously and to enlarge the gular sac with abrupt
and threatening movements. When they are in feed-
ing groups, larger males display aggressively in front of
females of the same age; smaller males and younger
animals retreat, allowing the dominant males to eat un-
disturbed. Aggressive conduct is short-lived, after which
the others approach and continue eating until the ac-
tion is repeated again. Dominant males also defend
basking perches, immediately attacking and displacing
intruders. These dominant males will also attempt to
mount small females that happen by them. A male
will pursue a female, mount and hold her with a bite
to the neck until she shakes herself free and escapes,
then headbob.

John Thorbjarnarson, IN
Wildlife Conservation
Manuel Alonso Tabet

A headstarted and recently r
iguana. Photo by Rick Huds

Anegada Island iguana (Cyclurapinguis)

Headstart Release Update
The ISG and British Virgin Islands National Parks Trust
released 24 headstarted iguanas back into the wild on
Anegada in October of 2003, with funding from the
International Iguana Foundation. The released igua-
nas ranged from 4 - 6 years of age and 750 - 2050
grams (mean = 1215g). Two release sites were used:
Windlass Bight (sandy coastal scrub) and Middle Cay
(inland limestone woodland). Both sites received 12
iguanas with an equal sex ratio and similar size distri-
bution. The release strategy was designed to compare
the success of different sized animals in two markedly
different habitat types.
Since the fall release, there have been follow-
up field trips in November, January, and March to
monitor the status of the released iguanas. To date,
the released animals have experienced an 84% survival
rate. Two animals have been lost at each study site.
Of the four animals that died, three were males, and
all were of medium size (890 - 1170g; mean = 1065g).
The four smallest animals released (750 - 880g; mean
= 823g) are still alive and doing well. Because of the
high survival rate of the smallest animals released, we
plan to decrease the minimum size of animals released
this fall from 750g to 550g. Evaluating the success of
incrementally smaller size classes over a number of years
will allow us to determine the optimum size for release
without risking the loss of a large number of animals.
The released animals appear
to be adjusting well to life in the
wild. Six individuals have con-
structed burrows at the sandy
scrub field site and most ani-
mals at both sites are showing
retreat site fidelity. The animals
released in the rocky woodland
are utilizing existing rock crev-
ices for retreats. During the No-
vember trip, all of the 22 ani-
mals remaining at that time
were recaptured and all but four
animals had increased in weight
(mean gain = 136g). Five ani-
mals were recaptured in March,
and all had gained weight since
released Anegada Island November (mean gain = 106g).

During March, most of the iguanas were found in the
same general area where they were last observed dur-
ing the January trip. To date, the animals have moved
between 13 and 391 meters from their respective re-
lease sites. We anticipate that some of the females re-
leased will lay eggs for the first time this reproductive
season and we hope to document successful nesting
during a trip scheduled for July. Plans are underway
to release another 24 headstarted animals in October.

Kelly Bradley
Dallas Zoo
kabradleyl 3@hotmail.com

Species Recovery Plan Workshop
In response to the need for a unified conservation strat-
egy for the critically endangered Anegada Island iguana,
Cyclura pinguis, a Species Recovery Plan (SRP) work-
shop was recently conducted at the Miami Metrozoo
from April 1 - 2, 2004. Workshop participants repre-
sented the IUCN Iguana Specialist Group (ISG) and
the National Parks Trust of the British Virgin Islands
(BVINPT). Those present (pictured left to right be-
low) included Kelly Bradley (Dallas Zoo), Allison
Alberts (ISG Co-Chair, San Diego Zoo), Quentin
Bloxam (Durrell Wildlife Conservation Trust), Lee
Pagni (San Diego Zoo), John Binns (Intl. Reptile Con-
servation Foundation), Rick Hudson (ISG Co-Chair,
Fort Worth Zoo), Steve Conners (Miami Metrozoo),
Joseph Smith-Abbott (BVINPT Director), and Fred
Burton (Blue Iguana Recovery Program).
To insure consistency in the ISG's Species
Recovery Planning process, Fred and
Quentin were brought in as facilitators.
Fred and Quentin previously ran success-
ful SRP workshops in Grand Cayman
(2001), Dominican Republic (2002) and
Turks & Caicos (2003).
Although an SRP workshop had al-
ready been conducted in July 2001 in
Tortola, that Plan was never finalized or for-
merly ratified, and was largely out of date.
And though significant progress has been
made since then on a number of impor-
tant fronts towards saving Cyclura pinguis
on Anegada, a number of "big picture" is-
sues still need to be addressed. A coordi-

nated plan of action, specifically dealing with local
public awareness and perceptions, land development
plans and protected areas, and invasive species control,
was needed. Thus the purpose of this workshop was
to review the 2001 draft plan and then condense it
into prioritized action components. Crucially impor-
tant to this process was that each actionable compo-
nent had a time line, a potential funding source if
needed, and a point person assigned who would be
responsible for implementation.
The next step is that BVINPT staff member
Nancy Woodfield will compile the document for re-
view and publication, which will then go to John Binns
for layout and creative design. Funds to publish a high
quality document have been identified (envisioned as
resembling the Ricord's Iguana SRP) and a late 2004
publication date is anticipated. This document will
prove useful on a number of fronts including guiding
the recovery plan process, providing accountability,
heightening local and international awareness for the
plight of the iguana, and highlighting critical funding
needs for granting agencies. However the most im-
portant goal that this document can serve is that it be
accepted and publicly ratified by the appropriate gov-
ernment bodies in the British Virgin Islands. This ac-
tion is vital to saving the Anegada Island iguana on
Anegada, and is essential to this species' long-term

ef Rick Hudson
Fort Worth Zoo

I he Anegada Island iguana Species Recovery Plan workshop participants.

Alberts, A.C., R.L. Carter, WK. Hayes, and E.E Mar-
tins. 2004. Iguanas: Biology and Conservation.
University of California Press, Berkeley. 341 pp.

Alberts, A.C., and T.D. Grant. 2003. Involving the
public in endangered species recovery through volun-
teer field research: a test case with Cuban iguanas.
Applied Environmental Education and Communica-
tion 2:147-151.

Arias, Y., S. Inchaustegui, and E. Rupp. 2004. Cy-
clura ricordii on the Barahona peninsula: a preliminary
report. Iguana 11(1):9-14.

Courchamp, E, J-L. Chapuis, M. Pascal. 2003. Mam-
mal invaders on islands: impact, control and control
impact. Biological Reviews 78: 347-383.

Gerber, G. 2004. An update of the ecology and con-
servation of Cyclura pinguis on Anegada. Iguana

Henderson, R.W. and R. Powell. 2003. Islands and
the Sea. Essays on Herpetological Exploration in the
West Indies. Contributions to Herpetology 20. Soci-
ety for the Study of Amphibians and Reptiles, Ithaca,
New York. 304 pp.

Levering, K. and G. Perry. 2003. Cyclurapinguis (Stout
iguana, Anegada rock iguana) juvenile predation. Her-
petological Review 34(4):367-368.

Perry, G., K. Levering, and N. Mitchell. 2003. Cy-
clura pinguis (Stout iguana, Anegada rock iguana) ju-
venile behavior. Herpetological Review 34(4):367.

ISG Contact Information

Allison Alberts, Co-Chair
Zoological Society of San Diego
Emaf: aalberts@sandlegozoo.org

Fredric Burton, Deputy Chair
National Trust for the Cayman Islands
Emath fiburton@candw.ky

Richard Hudson, Co-Chair
Fort Worth Zoo
Emaff: RH udson@fortworthzoo.org

Mlguel Garda, Deputy Chair
Department of Natural and Environmental
Resources, Puerto Rico
Email: mfguelag@umrch.edu

http://www, ucn-isg.org

ISG Newsletter
Published by the
Zoological Society of San Diego
Applied Conservation Division
P.O. Box 120551, San Diego, CA 92112

Tandora Grant
Allison Alberts