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Iguana Specialist Group
Volume 8 * Number 1 * Summer 2005
International Iguana Foundation Reaches Significant Milestone * The
February 2005 release of 16 Jamaican iguanas, Cyclura collei, brings to 100
the total number of iguanas released since 2003 with support and funding
from the IIE Twelve C. collei had been released previously in 2003 and 2004.
Forty- eight Anegada iguanas, C. pinguis, were repatriated to the wild in October
2003 and 2004, and 24 Grand Cayman blue iguanas, C. lewisi, were released
from December 2004 to January 2005. The pre-release health screening aspect
of these projects was funded by a grant from the Morris Animal Foundation
through the IIE
Jamaican Iguanas Released in Hellshire * On 26 February 2005 another
group of headstarted Jamaican iguanas, Cyclura collei, was repatriated to their
native habitat in the remote Hellshire Hills of southeastern coastal Jamaica. Six-
teen (8.8) iguanas were released as part of a joint collaborative endeavor between
the Hope Zoo, University of the West Indies (UWI), the International Iguana
Foundation, and the Fort Worth Zoo. The adult-sized iguanas were released
without radio transmitters and, based on previous survival rates, are considered
to be at low risk. However the new iguana biologist working in Hellshire, Rick
Van Veen, is in the field full-time now and is recording regular observations
on some of the iguanas. To make recognition easier in the bush, each iguana
is labeled with bright neon paint - pink for females, yellow for males - and
tagged with colored bead tags in the dorsal neck crest. The males were released
at randomly selected sites throughout the core iguana area in Hellshire in hopes
of dispersing them to reduce aggressive encounters. Females are released at the
two primary nest sites and allowed to disperse from there. Though imprinting
on these natal nesting areas has not been documented, recognition of these sites
may prove to be important when these females return to nest in the future. For
the past three years previously released female iguanas arrived at the nest sites and
deposited eggs, a strong indication that they are suc-
cessfully integrating with the wild breeding population.
The field research program is under the direc-
tion of Dr. Byron Wilson of UWI and the captive
iguana headstarting program is managed at Kingston's
Hope Zoo. A veterinary team from the Fort Worth
Zoo provided medical support and conducted pre-
release health screening exams on each iguana before
it was cleared to go. This aspect of the program was
funded by a grant from the Morris Animal Foundation.
This release was funded by the International
Iguana Foundation and brings to 76 the number of
Jamaican iguanas that have been released since 1996.
A negada Iguanas Released * Twenty-four (12.12)
I eadstarted Anegada iguanas, Cyclurapinguis, were
released on Anegada, British Virgin Islands (BVI), on 8
October 2004, bringing the total number to 48 in the
past two years. The first iguanas (12.12) were released
in October 2003 and based upon encouraging survi-
vorship data (20 of 24, or 84%), a second release was
conducted. The 2004 release used an identical strategy
to that employed in 2003 except that the minimum size
of released animals was reduced from 750g to 550g in
an effort to determine the minimum size iguana that
can coexist with feral cats. As in 2003, 12 iguanas
with surgically implanted transmitters were released
at each of two study sites, representing two distinct
habitat types (coastal sandy scrub and interior lime-
stone forest) located in the core iguana area. At more
than five months post-release, 22 animals survive and
are gaining weight (up to 260 g) and have established
home areas within 400m of their respective release sites.
Iguana movements and survival are being monitored
through radio tracking by Kelly Bradley (Dallas Zoo)
as part of a Masters program at the University of Texas
These releases are part of the Anegada Iguana
Recovery Program that began in 1997 with the con-
struction of a small headstart unit. This facility was
expanded in 1998, and more than 120 iguanas have
been headstarted here for eventual release. The re-
covery strategy seeks to boost the wild population of
adult iguanas by offsetting high juvenile mortality
due to cat predation. Other aspects of the program
include habitat mapping, population monitoring, field
research, nest site protection, collection of hatchlings
for headstart, local education and public awareness,
and nutritional, genetic and veterinary research. Plans
for a feral mammal control program are in the early
stages of development. Cyclurapinguis has undergone a
chronic population decline on Anegada since the 1960s
with current estimates for the wild population at -200.
Ranked Critically Endangered by the IUCN Red List,
this species is dependent on conservation intervention
to ensure their survival.
The International Iguana Foundation (IIF)
funded both the 2003 and 2004 releases, as well as other
components of the field program. Working in conjunc-
tion with the BVI National Parks Trust this program
has, since 1997, been managed cooperatively by staff
from the Fort Worth, Dallas, and San Diego Zoos, and
represents an excellent working example of a successful
zoo partnership. Since 1998 this program has been
supported with major grants by AZA's Conservation
Endowment Fund, Zoological Society of San Diego,
Morris Animal Foundation, Institute of Museum &
Library Services, and the IUCN/SSC Sir Peter Scott
Fund. Funding for specific projects was provided by the
Bergen County Zoo, Chicago Zoological Society, Chi-
cago Herp Society, Cleveland Metroparks Zoo, Dallas
Zoo, Fort Worth Zoo, John Ball Zoo, Pittsburgh Zoo,
Roger Williams Park Zoo, and the Wildlife Conserva-
IIF Executive Director
2005 Annual ISG Meeting
The annual Iguana Specialist Group meet-
ing will be held 5-9 November on Andros
island, Bahamas, and will include a Species
Management Workshop for the Andros
iguana. The IIF Board of Directors meet-
ing will follow, beginning the afternoon of
the 9th and continue through the 10th.
Sir Peter Scott Fund * The first recipients of
the Sir Peter Scott Fund for Conservation Action
Grants were announced 11 November 2004 by IUCN-
The World Conservation Union. The ebony forests of
Mauritius, the Anegada iguana, and the Critically En-
dangered Przewalski's gazelle are all set to benefit from
the first round of grants issued under the Sir Peter Scott
Fund for Conservation Action, created by the IUCN
Species Survival Commission (SSC).
The Sir Peter Scott Fund for Conservation
Action provides small grants (up to US$15,000) to
support the activities of its members in their work to
conserve threatened species around the globe. In many
parts of the world, a small amount of well-directed
money can have a significant impact.
In the inaugural round, three projects have
been selected to receive grants, $40,000 in total. David
Brackett, Chair of the SSC congratulated the project
leaders, saying "The selection committee was very
impressed with the quality of the proposals submitted.
They reflected the tremendous range of activity being
undertaken by the more than 120 Specialist Groups in
the SSC network. These three recipients are worthy
representatives of a much broader group of SSC
Restoration of globally important coastal
ebony forest, Ile aux Aigrettes, Mauritius. Dr John
Mauremootoo, SSC Indian Ocean Plant Special-
ist Group. This 26ha islet supports one of the last
remnants of this forest type in Mauritius (only 1%
of good native forest is left) but it is under constant
threat from degradation by invasive introduced plant
species. A restoration project, removing alien species
and re-establishing native ones was instigated in 1985
and 80% of the island's forests have been restored. This
grant will enable the restoration work to be completed,
safeguarding this unique habitat and its associated
Anegada iguana- implementation of the spe-
cies recovery plan. Richard Hudson (and others) SSC
Iguana Specialist Group. Endemic to Anegada island in
the British Virgin Islands, the Anegada iguana is clas-
sified as Critically Endangered on the IUCN Red List
of Threatened Species following an 80% population
decline since the late 1960s. Only 200 remain, and this
project aims to significantly enhance the recovery of this
species through an integrated programme of population
and habitat protection, releasing young iguanas reared
in captivity (to reduce predation of small iguanas), feral
mammal control, and building community support for
the recovery programme.
Monitoring population trends and habitat
quality of the Critically Endangered Przewalski's ga-
zelle. Dr Zhigang Jiang, SSC Conservation Breeding
and Re-introduction Specialist Groups. Przewalski's
gazelle is endemic to western China and is now con-
fined to a small area around Qinghai Lake. It is clas-
sified as Critically Endangered on the IUCN Red List
of Threatened Species, with an estimated population
of less than 250 animals, split into five isolated sub-
populations. There is no captive breeding population
and extinction is a real possibility. Continuing threats
include competition with livestock and extensive fenc-
ing, which prevents free movement between foraging
areas and disrupts mating. This project will carry out
sound, science-based research on the surviving gazelles
and their habitat in order to identify specific measures
for conservation action.
"The creation of the Sir Peter Scott Fund is
part of a suite of measures put in place in response to
the Voluntarism Study that was carried out by SSC in
2001. The study highlighted that our members need
more help in fundraising and securing grants," says
Jean-Christophe Vie, Acting Head of the IUCN Spe-
cies Programme. "This is a modest start but we shall
strive to mobilise more resources to guarantee the future
of this important Fund," he added.
Funds for the first allocation of grants were
generated by proceeds from sales of The Red Book: The
Extinction Crisis Face to Face, sales of The IUCN Red
List Collection, a series of soft toys created to promote
awareness of the threats to species, and the remaining
balance of the former Peter Scott Fund that was created
for the production of SSC's species Action Plans. Do-
nations to further the work are always appreciated.
For more information on the Sir Peter Scott
Fund for Conservation Action see: http://www.iucn.
Check the www.blueiguana.ky website for
recent issues of Blue Iguana Tales highlighting
Team Blue 2005's field efforts in the Salina
Reserve, QEII Botanic Park, and the East End.
Special thanks to IRCF and IIS for recent do-
nations to both this and the Jamaican iguana
Love is Blue
Chicago Tribune - February 11, 2005
By William Mullen
CHICAGO, ILLINOIS. When mating season rolls
around, the Shedd Aquarium's Grand Cayman iguanas
are decked out in the color of romance. Parents with
young children who spot a bright blue iguana at the
Shedd Aquarium in the next few weeks might consider
discreetly hustling the little ones toward the seahorse
exhibit or something else a little more innocuous. Mar-
ley and Eleanor, a breeding pair of Grand Cayman blue
iguanas, are going on display at the aquarium.
"In breeding season, when their reproductive
hormones rise to high levels in March and early April,
the color of the males changes to this amazing electric
blue," said Chuck Knapp, a Shedd population biologist
who is a world authority on iguanas.
Found only on Grand Cayman Island, a spot
of land in the Caribbean south of Cuba, the species
is thought to be the world's most endangered lizard.
Fewer than 25 of the dragon-like blue iguanas, which
can grow to 5 feet in length, survive in the wild. Ten
zoos and aquariums in the U.S. are trying to breed them
in captivity to send offspring back to Grand Cayman
Island for re-introduction into wild areas. The Shedd
has built an elaborately engineered exhibit case as a
part of the breeding effort. Marley made his debut
Thursday, and Eleanor will join him later.
Female blue iguanas also take on a more defi-
nite blue hue in the mating season, though a lighter,
powdery color. The rest of the year, the skin of both
sexes is a drabber blue-brown.
"The color change at the mating season, es-
pecially for the males, seems to be a way of attracting
prospective female mates," said Knapp. "The males
are very aggressive in the mating season. He will try to
scare off other males by confronting them with these
large-amplitude head bobs. When he presents himself
to a female, he uses a different, short little vibratory
head bob to see if she is receptive. If she is, she gives
him a head bob in return."
It sounds simple, but efforts to breed the spe-
cies in captivity in the U.S. have been spotty, at best,
ac the hllin iln-ana wtere lmrnc anne in the wilA heAnrf
anybody began to study them in their natural state.
"There are a lot of variabilities in the natural
world that might affect breeding that we just don't know
about," said Allison Alberts, a conservation specialist
at the San Diego Zoo. "We're still learning what we
have to provide them in captive situations to encourage
breeding. We know nutrition is important. So are the
right levels of ultraviolet light in the exhibit and the
social situations you place the animals in."
When Grand Cayman Island was just a sleepy
fisherman's enclave, the blue iguana was the biggest
native land animal and had few predators to fear. In
the latter half of the 20th Century, however, Grand
Cayman became an upscale center of luxury resorts
and offshore banking, bringing more than 30,000
permanent human residents.
Threat grew. With the humans came pet dogs,
cats and snakes. Feral dogs hunted down adult iguanas.
Feral cats and snakes--not to mention introduced rat
species--sought out iguana eggs and hatchlings. New
homes, hotels and golf courses took over prime iguana
habitats, and the lizards became common roadkill on
newly built roads.
"In 1993 there were 200 to 250 of them left in
the wild, but now we believe there are only 10 to 25
left," said Rick Hudson, a Ft. Worth zoo conservation
biologist. "Almost every Caribbean island has its own
iguana species, and the survival of most of them is nearly
as tenuous," said Hudson, who with Alberts co-chairs
a group of scientists overseeing Caribbean iguana con-
servation efforts. "There are 16 iguana species in the
Caribbean, and nine are ranked critically endangered,"
he said. "They won't survive without some form of
conservation intervention. The Grand Cayman blue
iguana is the most endangered of all of them."
A group of Grand Cayman residents, alarmed in
the 1990s at seeing the island's largest animal plunging
toward extinction, began a rescue effort, establishing
two protected areas and building, with international
help, a local breeding facility. Now all the captive
blue iguanas on Grand Cayman and in 10 U.S. zoos
and aquariums are being treated as a single breeding
population. There are 90 iguanas in the Grand Cay-
man breeding facility, and another 250 babies are
being raised until they are old enough for release into
protected reserve areas.
The genetic history of all the iguanas in Grand
Cayman and the 40 iguanas in the U.S. has been de-
termined and out on file so a committee headed by
Hudson can oversee which ones are paired for mating
to avoid inbreeding. U.S. captive breeding efforts for
blue iguanas fell apart in the 1990s when participating
institutions discovered their early efforts were tainted by
misidentification of species, producing hybrid offspring
and accidental pairings of brothers and sisters.
Starting anew, the Shedd brought in Marley
as a young adult in 1999, having obtained the female,
Eleanor, as a hatchling in 1995. They had been housed
in a basement habitat until now, and so far they have
failed to produce fertilized eggs.
New habitat. The Shedd spent $235,000
building a new 1,200-square-foot exhibit in hopes of
producing hatchlings. Taking up an entire wall in the
aquarium's Tropical Waters Gallery, the blue iguana habi-
tat, built to resemble a rocky Grand Cayman seashore,
has several features built to encourage breeding. "They
now will live directly under skylights," said George Par-
sons, the aquarium's collection director, "so that they will
have the natural seasonal changes in sunlight to stimulate
their natural cycles. We have installed ultraviolet lights
to replace the natural ultraviolet rays blocked by the
skylight windows. The temperature is maintained at
85 degrees in the air, and we have hot rocks strategically
placed throughout the exhibit heated to 102 degrees,
where they will like to sit and bask in the UV rays."
Except during the breeding season, wild iguanas
live solitary lives. To keep Marley and Eleanor from
getting on each other's nerves, the habitat has many
projections and corners so they can stay out of each
other's sight. In nature, female iguanas bury fertilized
eggs in the sand, then cover the burrow entrance to hide
the eggs from intruders. The Shedd has built two cave
entrances into the exhibit rockwork that lead to sand-
filled nesting dens that officials hope Eleanor will one
day use for her fertilized eggs.
To get them established in their new home,
Marley will remain by himself in the new exhibit for a
couple of weeks to acclimate himself; then he will return
to the basement while Eleanor gets her chance. Before
the end of the mating season, however, they will be on
display together in the new exhibit. The exhibit includes
a 4,000-gallon pool stocked with life commonly found
near the shore of Grand Cayman.
"As an aquarium, we of course feature aquatic
life," said Parsons, "but we see the need to link up how
these terrestrial and aquatic environments merge along
shorelines, and how human presence can endanger
SOS Call for Ancient Blue Iguana
BBC News - May 23, 2005
By Georgina Kenyon
CAYMAN ISLANDS. Cayman Island scientists are
calling for assistance to pull a unique species of blue
iguana back from the brink. The animal has a long
history: DNA evidence suggests it has been around for
the past three million years. However, the mere 25 of
them left on Grand Cayman seemed recently to face
a dismal future.
"Time is obviously not on the side of this
remarkable creature," said Fred Burton, director of
the Blue Iguana Recovery Programme (BIRP). "But
there are no insurmountable biological, political, or
social barriers to the re-establishment of a viable wild
population. "Saving the blue iguana really boils down
to the human financial resources we can direct to the
On the brink. The BIRP is significant in the
study of how a species can be brought back from the
brink of extinction. With a heady mixture of science,
iguana ingenuity, understanding of iguana psychol-
ogy, and local and international support and funding
- scientists believe they may just be able to bring the
iguanas back to a critical mass required to sustain a
The blue iguana's problems stem from humans,
though for the most part the damage to the iguanas
has been quite unintended. The first European set-
tlers arrived nearly 300 years ago, and the pets that
they brought with them, such as dogs and cats have
continued to push the iguanas back from the coast and
into less hospitable inland areas. The displacement and
land-use change has accelerated with a major human
population boom in the last half-century.
The blue iguanas, named because of their skin
which turns slowly from slate grey to blue throughout
the day as the sun shines, were once shot and eaten by
people and are still attacked by pets. The iguanas do not
instinctively recognize dogs and cats as lethal predators
and the first chance to learn often ends in tragedy.
The BIRP hatches and rears blue iguanas for
two years, so sparing them the severe mortality that
would usually decimate a year's hatch. The pioneer
blue iguanas are then released back into the wild and
radio-tracked as they mature and start breeding. These
studies are providing vital information for the develop-
ment and management of a protected area.
The iguanas have strong personalities and are
superbly adapted to their natural environment and
they are learning to cope with today's world in different
ways. As fast learners, the iguanas have expanded their
natural diet of some 50 or so native plant species, to
over 130 by discovering new edible plants brought to
the islands by horticulturalists and landscapers. They
can also adapt to a man-made environment (if there
are no dogs or cats); they are as happy sleeping under
a wooden shed as in a natural rock hole.
Playing cupid. Hope also lies with the design
by BIRP workers of honeymoon suites for the iguanas
breeding in captivity which include specially con-
structed retreats and a carefully prepared diet of fruits,
flowers, and assorted greenery.
"Iguanas are fairly basic in this area. Good
food, plenty of sunshine, and a nice place to nest and
hang out and they will pretty much get on with it,"
said Dr Matthew Cottam, special projects officer at the
Cayman Islands Department of the Environment, who
works with the BIRP.
But is it too late for the iguanas? Can they be
"The captive breeding programme is going
from strength to strength," said Fred Burton. "Our
monitored releases are working brilliantly so far. If
we can protect enough habitat and maintain it free of
unnatural predators, there is every reason to hope we
can give the blue iguanas their future back. This is one
species we can save."
Mona Island iguana (Cyclura cornuta stejnegeri)
The Successful Release of Head-start Mona
The Mona Island iguana (Cyclura cornuta stejnegeri)
was listed as endangered in The Regulation to Govern
the Threatened and Endangered Species in The Com-
monwealth of Puerto Rico (2004) and in the Recovery
Plan for the Mona Island Iguana (USFW 1984). The
reduced recruitment of juveniles into the adult popu-
lation due to exotic mammal predation provoked the
implementation of a head-start program in 1999. This
Recaptured iguana "Xena", with an inactive internal
transmitter (releasedApril2002, recaptured July 2004) held
by Alberto Alvarez. Photo by Miguel Garcia.
initiative was developed by the Puerto Rico Department
of Natural and Environmental Resources (PRDNER),
with collaboration of the IUCN Iguana Specialist
Group, the US Fish and Wildlife Service, the Toledo
Zoological Gardens and assistance from the University
of Puerto Rico.
By March 2005, 69 head-start iguanas have
been released in several nesting areas of the coastal
plain where they were collected as hatchlings in 1999
and 2000. These iguanas had gained biomass rapidly,
reaching releasing conditions after 18 months in captiv-
ity. The mean body mass of the released individuals was
949 grams �184, with a mean SVL of 25.7 cm �1.8.
Twenty-three (23) iguanas have been recaptured and
three of them are currently being radio-tracked. Six
animals were recaptured twice, and another one three
times in a 2.5 year period. Most of the recaptures were
made about 500 meters from their respective release
areas. The farthest animal recaptured was 700 meters
from the release point. All the animals were healthy
and active. Based on recapture information, most of the
released iguanas grew at a higher rate than in captivity.
Some iguanas gained more than two kilograms in less
than two years. Most of them had lost their external
marks (beads) and these were replaced with new ones
in a different place of the crest. Four of the recaptured
iguanas had inactive internal transmitters implanted in
During the 2004 season, two nesting females
observed turned out to be head-start iguanas released in
August 2002. Unfortunately, one of the nesting females
was found dead, apparently hit by a vehicle. Hatch-
lings of one of those nests emerged and were collected
in October 2004. Next releases will be made in Playa
de Pijaros area with iguanas from this site. We could
greatly increase the number of released iguanas. Nev-
ertheless, it is important to first determine scientifically
the number of iguanas needed to cause a sustainable
growth of the population.
Miguel A. Garcia1'2, Alberto O. Alvarez1'
and Nestor Perez2
1Puerto Rico Department of Natural and
2 University of Puerto Rico-Rio Piedras
M. Garcia: email@example.com
Mona Iguana Nesting Seasons 2003 and 2004
We monitored the hatching success of 23 nests (273
eggs) of the Mona Island iguana (Cyclura cornuta
stejnegeri) during October 2003 and 2004 nesting sea-
sons. This initiative is part of a paternity study being
conducted at the Biology Department of the University
of Puerto Rico. From the 23 females, seven nested in
2003 and 2004. Their offspring were collected over
the two years, to determine if the fathers of those
hatchlings were the same during the two consecutive
years of the study. Mother iguanas, and most of the
potential fathers, are well known iguanas living year-
round in three study areas, most of which have been
monitored by radio telemetry through climatic and
reproductive seasons. In addition, all hatchlings from
the 23 nests were measured sexed, pit-tagged, and tis-
sue sampled. Radio telemetry studies on Mona Island
iguana hatchlings showed that natal dispersal lasted up
to three weeks (Perez-Buitrago 2000). Therefore, most
of the hatchlings were kept in captivity for a month to
prevent natal dispersal, and then released into the sur-
rounding areas where they were originally collected to
try to obtain information regarding survival and growth
rates. To date, no recaptures of those hatchlings have
been conducted even though the release areas are very
Thirty hatchlings from each year are still in
captivity as part of a head-start program headed by the
Puerto Rico Department of Natural and Environmental
Resources (PRDNER) and will be released in their re-
spective collection areas when they reach the final target
size of at least 700 g and 22 cm SVL. Hatching success
was 77% and 55% in 2003 and 2004, respectively. The
55% obtained in 2004 was mostly due to three indi-
viduals, two very large female that laid 24 eggs (twice as
much as the average reported of 12 eggs per nest!!) and a
young female (probably a first-year mother) that laid 11
eggs. Eggs from both nests failed to develop and were
possibly infertile (i.e. only yolk inside). However, we
cannot discard the possibility that embryos aborted in
the very early stages of development. Excluding those
"bad" nests from the hatching success calculation, it
rose to 75% for 2004.
The 2003 hatching season gave us some experi-
ence to artificially incubate eggs successfully. During
that season, we were forced to move a nest that was laid
on a heavy traffic road. The hatching success for that
nest was 100%, proving that it was possible to relocate
Mona Island iguana nests with success. In 2004, we
artificially incubated 33 eggs, from multiple nests, that
showed delayed hatching relative to their siblings. The
hatching success of these eggs was 91%. Two of the
incubated eggs were accidentally broken when handled,
but also hatched successfully. The broken eggshells
were replaced with waterproof paper pieces from a field
notebook and sprayed with water to provide darkness
Illustration by John Bendon of iguana #27, one of the
friendliest animals that was once radiotagged and nested
close to the research facility in 2003 and 2004.
During our observations of nesting activity
on Mona, we observed several novel events. First, we
noticed that seven hatchlings became sick soon after
hatching. Six out of the seven were from the same nest
and all developed similar disease pathologies. When
the disease began, individuals had "dropping eyeballs",
with the pupil discernible just above the lower eyelid.
As it progressed, the eyes became very sticky because
of lachrymal secretions and often became sealed shut.
The eyes themselves looked collapsed and all animals
were apparently blind. The affected eyes were cleaned
regularly with water but failed to recover. Eventually,
animals stopped drinking and became listless and
limp. All died and two dead hatchlings were sent to
the Toledo Zoo for necropsy, where head veterinarian
(Dr. Tim Reichard) suggested the condition was likely
a bacterial or fungal infection that might have been
acquired during the egg stage or right after hatching.
In addition, we noted that six females re-visited
their respective nesting places at the exact time when
the eggs were expected to hatch. The 'visit' consisted
of iguanas 'hanging around' right after collecting the
hatchlings from the nests. These iguanas checked the
excavated nests and pushed soil around with their snout.
It is unclear if they were looking for the chamber or
were simply attracted by the activity. (e.g. soil removal).
Moreover, two different females refilled the cavity with
soil that we made while collecting the hatchlings. The
longest movement documented for a female showing
this apparent homing (nesting) behaviour was 300 m
from her year-round core area. The typical core area for
Mona adult iguanas does not exceed 70 m in diameter
Nestor Perez-Buitrago1'3, John Bendon,
Miguel Garcfa1'2, Alberto Alvarez2, and
1 University of Puerto Rico, Biology Department
2 Puerto Rico Department of Natural and
N. Perez-Buitrago: firstname.lastname@example.org
Andros Island iguana (Cyclura cychlura cychlura)
2004 Shedd Aquarium Research Update,
9 May to 13 June 2004
The beginning of the 2004 iguana field research proved
to be very successful. The season was initiated with a
seven-day John G. Shedd Aquarium's research expedi-
tion aboard the R/V Coral Reef II. We concentrated
the majority of the work at two long-term study sites:
Sandy Cay in South Bight, and a tri-lobed peninsula
(Dissertation Point) located in Lisbon Creek off the
east/southeast portion of Mangrove Cay. Work con-
sisted of continuing with our mark/recapture sequences,
exploring for new, and monitoring old nests for activity,
and radio tracking five females on Sandy Cay.
We captured 36 iguanas (22 males/14 females;
19 recaptures) ranging from 280 grams to 6.88 kg in
body mass, and 21.6 to 52.3 cm snout vent length. We
attempted to track females with 2003 radio transmit-
ters that had remaining battery power. Unfortunately,
the batteries expired soon after attachment for most
iguanas. We do have good data for one female, which
documents her extraordinary movement patterns in
search of a suitable oviposition site. She was eventually
tracked to her mound nest on 6 June.
On 10 May we discovered the first nest of the
season - a recently oviposited clutch of eggs on Linder
Cay, Lisbon Creek. The eggs were deposited in a ter-
mite mound adjacent to a mangrove flat by the same
female that used the mound in 2003. The same female
was also the first recorded user of a mound in 2003.
Using the Shedd Aquarium research expedition
as a building block, Audrey Owens and I continued
Hunting camp at the mouth of Honeycutt Creek.
Photo by Chuck Knapp.
with the project until 14 June. We captured 22 iguanas
(3 males, 18 females, 1 juvenile; 9 recaptures) ranging
from 47 grams to 9.17 kg in mass, and 10.3 to 56.5 cm
snout vent length. The skewed sex ratio of captured
individuals is an artifact of our nesting ecology study
and subsequent captures of guarding females.
We excavated 22 nests at seven sites and re-
corded data including clutch size and morphometrics,
mound dimensions, and nesting female body size.
We also placed thermal data loggers in ten mounds
and took detailed measurements and drawings of the
internal mound structures. A significant discovery was
the apparent facultative nesting behavior of females.
On two occasions, we documented females using sand
instead of termite mounds for oviposition. The first
occurrence was documented from an unmarked female
that eluded capture. The second recording occurred
after a female from 2003 destroyed her old mound by
over-aggressive digging. Her nest was found 1.5 weeks
later -300 meters south of her 2003 mound. The eggs
were deposited in course sand -10 cm below the surface.
The site was only -50 cm above the high tide mark (see
photo). Both occurrences of using sand for oviposition
were recorded on North Dissertation Point.
Of the 12 nests known to have been used in
2003, eight were used by new females. In one instance,
the mound of a 2003 user was destroyed and the female
appeared 300 meters away at another nest used in 2003
and evicted the resident female to deposit her clutch
of eggs. We also documented an unknown (prior to
2004) female get evicted from the mound after depos-
iting her eggs. Before the female was evicted, the eggs
were discovered by white crabs (Cardisoma gunahumi)
and destroyed. Two days later, a new unmarked female
deposited her eggs in the mound. We documented a
second nest completely destroyed because of crabs. We
suspect additional predation in the weeks following
oviposition. Mean clutch size was 9.4 (range 5 to 18).
Additional clutch data are still being analyzed.
We continued our in-depth ethnographic inter-
views with locals. We discovered in conversations that
six goats have been put on Linder Cay. This is a concern
because the cay provides very good habitat for iguanas.
Additionally, we heard anecdotal stories of people stay-
ing at the hunting camp at the mouth of Honeycutt
Creek during the last week ofApril. A bonefish guide
from Tiamo Resorts was in the area and the men offered
him iguanas for sale at $150 per animal. They allegedly
had 40 iguanas in their possession and were bringing
Cay). Photo by
them to North Andros for sale. We heard another story
about men from Mangrove Cay going to the same area
at the end of 2003 and collected ten iguanas for sale
on North Andros for $50 per animal. The price range
is corroborated with multiple independent interviews
over the past three years, though I think $50 is more
realistic and most often quoted.
We visited the camp on 23 May and found the
area very much in use. More garbage than usual was
around and the area was recently burned. A new tarp
was also in place over the wooden frame that is normally
in the camp. Shed iguana skin was all over the camp. A
step could not be taken without stepping on skin. We
found iguana bones and an intact skull. We also found
the skull of a green sea turtle. It is evident that illegal
hunting is still occurring and for commercial purposes.
I propose immediate action be taken such as enforcing
existing laws or initiating warden protection.
Acknowledgments. I would like to thank the Shedd
Aquarium volunteers for making the start of the sea-
son such a success. The work could not be completed
without Shedd Aquarium, Audrey Owens, and Tiamo
Resorts of South Andros.
Charles Knapp 1)
John G. Shedd Aquarium
University of Florida
Allen Cays iguana (Cyclura cychlura inornata)
Research Report 10 to 18 May 2004
Allen Cays. This spring in the northern Bahamas was
one of windy, cool, and dry conditions, and that pat-
tern continued during our survey work. The vegetation
in the Allen Cays reflected the drought with colors
dominated by brown and orange rather than green,
and little fruiting and flowering. The weather not only
reduced the available high-quality food for the iguanas,
but it also reduced tourist boat visitation, and hence,
food supplementation of the iguanas by humans. As
a result many individual recaptured iguanas weighed
less than they did a year ago.
Winds blew nearly constantly at 20 knots dur-
ing our visit, keeping temperatures cool. As a result
iguanas were late to emerge in the mornings, avoided
the windward sides of the islands when possible, and
retreated early in the evening. However, with a field
team comprised mostly of students from previous trips,
we captured a record total 535 Allen Cays iguanas this
year (including 27 carcasses). Representing more than
half of all existing individuals. We captured 376 iguanas
(69% of them recaptures) on Leaf Cay and 124 (90%
recaptures) on U Cay. First year iguanas were particu-
larly obvious this year on Leaf Cay, and we captured
42 of them. We have now accumulated 5043 iguana
captures over the past 24 years.
We found a disturbing number of carcasses on
both Leaf (18) and U Cays (9) this year (compared to
only six total last year, but 26 and 22 during six weeks
of field work each year in 2002 and 2001, respectively).
Many of these were large males, continuing a pattern of
reduction in the number of large males on the islands.
Indeed, of 30 large males (> 40 cm SVL) captured on
U Cay in 2000, only 27 were recaptured in 2001, 24
in 2002, 17 in 2003, and 11 in 2004. This suggests an
annual survival rate of only about 78%, well below the
over 90% that we believe is normal. Similarly, on Leaf
Cay, of 15 large males alive in 2002, only nine (60%)
were alive/captured in 2003 and five of those (56%)
were alive/captured in 2004; 12 of those from 2002
were from the big west beach (i.e., likely to be caught
if alive) and only seven of those (58%) were caught
in 2003 and only five of those (71%) were caught
in 2004. There can be no doubt that large males are
disappearing (some through unnatural death, some to
unauthorized removal) from the Cavs at an alarming
rate. All carcasses and skeletons were salvaged and given
to Sandra Buckner for archival purposes.
The removal of large males is also evidenced by
the recent decline in the mean size (SVL in cm) of the
largest ten males captured on Leaf Cay over the past ten
years: 42.9 in 1994, 42.9 in 1995, 42.3 in 1996, 44.0
in 1998, 43.0 in 2000, 42.1 in 2001, 42.0 in 2002,
41.4 in 2003, and 40.8 this year.
As we recommended in previous reports it
seems that there is a desperate need for the construc-
tion of a bilingual "iguana information kiosk" on both
Leaf and U Cays. Not only could this provide general
natural history information to interested tourists, but
it could also explain the dangers of harassing, improp-
erly feeding, and relocating the iguanas, as well as the
potential threats presented by feral animals.
In previous years we had found three mum-
mified carcasses or partial skeletons of iguanas wedged
in the crotches of trees on Leaf Cay (as well once for
Cyclura rileyi on Bush Hill Cay). This year we en-
countered a subadult trapped between the multiple
trunks of a tree (cf. Drypetes diversifolia) on Leaf Cay.
The animal was emaciated and weak, and had appar-
ently been trapped for some time. We rehydrated and
hand fed it over the next 36 hours, and then released it
near where it had been found. However, we were not
certain whether it would recover. Clearly, this means
of accidental death is more common than might be
Windy conditions prevented our visit to Flat
Rock ReefCay; however, we did walk the entire length
of Allen Cay and captured nine "giant" iguanas there,
including two females and seven males (seven of the
total being recaptures, and two of those being animals
Juvenile Cyclura cychlura inornata.
Photo by John Iverson.
originally marked on Leaf Cay!). We have now marked
a total of 15 iguanas on Allen Cay (including the two
recent mysterious introductions from Leaf Cay), and
we are confident that fewer than five additional ani-
mals could be present. This year we neither saw nor
heard evidence of juveniles, so we are still uncertain if
reproduction is possible on this Cay given the lack of
apparent nesting substrates. As evidenced by the great
numbers of fresh carcasses, the high rate of predation
on adult Audubon's Shearwaters on Allen Cay contin-
ues, primarily by local barn owls. Since iguanas seem
not to be responsible for that predation, it may be time
to reconsider our earlier plan to carry sand to upland
sites on Allen Cay to create iguana nesting habitat on
Stephanie James of the Wildlife Conservation
Society at the Bronx Zoo in New York joined us for our
first three days in the Allen Cays, and collected fecal
and blood samples from 41 iguanas (38 from Leaf Cay
and three from Allen Cay) for baseline health screening.
We are hopeful that funding will permit her to collect
blood from U Cay animals in 2005.
Tail breaks frequencies remain quite low for the
Allen Cay iguanas: Leaf Cay females, 9.0%, Leaf Cay
males, 7.2%; U Cay females, 11.3%; U Cay males,
11.9%. Sex ratios were not significantly different from
unity, with 153 sexable females and 167 sexable males
captured on Leaf Cay, and 62 sexable females and 59
sexable males captured on U Cay.
We once again recorded the precise capture
location of nearly every iguana this year. As has been
the pattern, most captures were made on the big west
beach of Leaf Cay (only ca. 2% of the total island
area), with 173 of 371 (47%) being made there (58%
in 2003; 44% in 2002). The attraction of the iguanas
to the feeding beach is obvious.
This year we implanted an additional 66 elec-
tronic identification (PIT) tags in iguanas, and have
now PIT-tagged a total of 572 lizards. We had only
one PIT tag failure this year. The failure rate of PIT
tags has been quite low our 11 years of using them, as
has been the failure rate of toe clips due to natural toe
loss. We were even able to identify 7 of 27 carcasses
that we found by scanning the remains and the nearby
sand. We plan to continue to PIT tag 50-70 additional
larger animals each year as funds allow.
Bush Hill Cay. For the third year in a row we visited
Bush Hill Cav to census the introduced population of
Cyclura rileyi there. We captured and processed iguana
in the afternoon of 17 May and the early morning
of 18 May. This year we caught 105 iguanas (45
males, 60 females; 63 new, 42 recaptures; plus one
fresh carcass left on the Cay). We have now marked
a total of 192 iguanas on Bush Hill and recorded 58
Last year a simple Lincoln Index using
2002-03 recapture data (and assuming no mortality
between sampling) estimated the adult population
on Bush Hill at 319. The same calculation based on
this year's adult recaptures (126 previously marked;
105 captures, including 42 recaptures) estimated 315
individuals. In addition, for the 68 iguanas caught
in 2003, we recaptured 22 of them in 2004, for an
estimate of 325 individuals. Though crude, these
estimates are consistent and seem to be reasonable
minimum estimates based on our observations.
However, juveniles are still relatively uncommon on
the Cay considering the size of the adult population.
We suspect that the high density of adults may result
in cannibalism of small juveniles.
Tail break frequency on Bush Hill Cay (53.3%
in females; 53.3% in males) remains over five times
the rate in the Allen Cays. In addition, of the 63
new iguanas captured this year, 18 had toes missing
naturally (9 males, 8 females, 1 unsexed). Many oth-
ers showed clear evidence of bite marks from other
iguanas. Given the high rate of natural toe loss on
Bush Hill, the use of PIT tags there seems warranted
for identification purposes. We captured only one
iguana that had neck beads present, left from Bill
Hayes' work on the cay in 1997.
Based on 50 recaptures of adult Bush Hill
iguanas over the past three years, adult males (n =
28) grew an average of 0.37 cm/yr (range: -1.2 to 3.2
cm), and adult females (n = 22) grew an average of
0.30 cm/yr (range: -1.1 to 2.0 cm). Von Bertalanfy
growth equations calculated from those data and the
single capture of an 11.2 cm SVL juvenile captured
21 May 2003 and estimated to be 0.7 years old are:
male, SVL = 35.16 (1-57.92-0.135t); female, SVL
= 31.47(1-121.25-0.131t). The latter preliminary
equation suggests that females reach 24 cm SVL in
about ten years.
As previously reported Bush Hill Cay iguanas
are greatly polymorphic in color (from brilliant yel-
low to bright mottled orange to gray, brown and even
almost cream colored). Yellow iguanas captured this
year included both males (n = 3) and females (n = 2) and
remain an enigma. The remaining morphs seem to in-
clude a continuum from very dull colored (gray, brown,
cream) to almost uniform orange. Intermediates are
mottled with increasing amounts of orange. Although
color is not precisely dimorphic, there is a tendency for
females to be brown or gray or gray mottled (53%),
and for males to be orange or orange mottled (63%).
Studies of the basis for this color variation (including its
genetic versus environmental basis and its relationship
to social behavior) are sorely needed.
All Bush Hill Cay data have been forwarded
to Drs. Hayes and Carter for their continuing studies
of this species (as well as to Sandra Buckner), and are
available to others upon request.
Acknowledgments. This work would not have been
possible without the continued support by Mrs. Sandra
Buckner, the Bahamas National Trust, the Bahamas
Government, Powerboat Adventures, 7 Seas Charters,
and John Alford and Barbara Thompson. Maurice
Isaacs of the Dept. of Agriculture granted permits for
our research, and Lynn Gape of the Bahamas National
Trust, and Ray Darville, warden of the Exuma Cays
Land and Sea Park, granted us permission to visit Bush
Hill Cay. In addition, the financial support of Dr. Ned
and Sally Test, the Cope Museum Fund of Earlham
College, and 95 different Earlham College students
(and six faculty) over the past 24 years is greatly ap-
John Iverson I
Cuban iguana (Cyclura nubila nubila)
Selection of habitat of Cuban iguana (Cyclura nubila
nubila) in Juan Garcia Cay, San Felipe's Cays, Cuba.
Edited from Spanish by ISG newsletter editors.
This article summarizes a study on habitat selection
by the Cuban iguanas (Cyclura nubila nubila) carried
out on Juan Garcia Cay, San Felipe's Cays, south of
Pinar del Rio, Cuba from February, 2000 to January,
2001. The following vegetation associations on sandy
substratum were identified: Batis maritima grassland,
coast xeromorphic shrub, (sandy) coast vegetation, and
herbaceous Rinchospora dominated vegetation. Use of
each of these habitats was evaluated in terms of relative
abundance of iguanas, taking into account the number
of active individuals found, fecal deposits, and retreat
sites during 30 minute transects, The timing of surveys
was randomized across habitats, with an equal propor-
tion of observations occurring during the dry and wet
seasons. To determine habitat selection we used the
methodology of Thomas and Taylor (1990) and Neu
et al. (1974), which calculates percent use relative to
percent of availability of each studied habitat.
Results and discussion. The relative abundance of
active iguanas shows an evident pattern of gradual
decrease from Rischospora habitat (6.8 iguanas/hect-
are) to coast vegetation (1.2 iguanas/hectare), with
intermediate values in Batis and coast xeromorphic
shrub (Table I). Statistically, the most preferred and
least preferred habitats differ significantly from each
other and from the intermediate habitats, but there is
no significant difference in preference between sandy
coast vegetation and coast xeromorphic shrub. These
habitats appear to function equally well with regard to
iguana density, despite their very different ecological
characteristics. The relative abundance of iguanas in
Batis and coast xeromorphic shrub seems to be typical
compared to abundance of iguanas in these habitats on
other cays. The small number of iguanas found in coast
vegetation may be due to the fact that this is neither a
feeding nor a shelter area, while the high value recorded
in the Rinchospora habitat is possibly due to the fact that
the shelters are more concentrated in this area.
The coast xeomorphic shrub shows the greatest
density of retreats per 30 minutes, followed by Rincho-
spora and Batis. All mean values for retreats differed
across habitats. No retreat sites were detected in coast
vegetation, perhaps due to three main factors: high ex-
posure with little vegetation cover and very loose sandy
subtratum. The mean frequency of fecal deposits per
habitat do not differ statiscally for Rinchospora, Batis,
and coast xeromorphic shrub, but in coast vegetation
we detected feces about twice as often as in other
habitats, a difference that was statistically significant.
This result coincides perfectly with information given
by local fishermen who affirm that iguanas go early in
the day to the coast to defecate and later penetrate into
the cay, where they only defecate rarely while they are
engaged in other activities.
The degree of habitat selectivity in relation to
the three analyzed variables (active iguanas, retreats, and
fecal deposits) is shown in Table 2. The iguanas prefer
Rinchcospora and Batis habitats, whereas coast xeromor-
phic shrub is not preferred and coast vegetation is used
in proportion to its abundance in the environment.
Assuming equal activity and detection probability
among habitats and relative abundance directly pro-
portional to density, then there is high iguana density
in Rinchospora and Batis, even if they do not appear to
be optimal habitats (in terms of shelter and food plant
species) for iguanas. It is possible that these habitats
function as sink areas, where young and old individu-
als go when they are rejected from the best habitat by
territorial adults (which may explain the lower density
in apparently higher quality habitats), a phenomenon
known as a despotic distribution (Fretwell and Lucas,
1970; Van Home, 1983).
The preferred habitat for excavation of retreats
is Rinchospora, despite the small area, because this
habitat has highly favorable conditions for excavation,
including high cover and fine sand. The finding that
Batis is not preferred is expected because there is no
adequate substratum for excavation of shelters despite
its relatively large area. Coast xeromorphic shrub is
used in proportion to its abundance. Feces are depos-
ited preferentially in Rinchospora and coast vegetation.
In coast vegetation, this result is explained by the ob-
served pattern of early morning migration to beaches
already mentioned. This may simultaneously explain
the lack of preferential use of coast xeromorphic shrub
by iguanas for defecation. Batis is used in proportion
to its abundance.
In summary, all habitats studied seem to be
important for iguanas to carry out their vital daily
Fretwell, S.D. and H.L. Lucas. 1970. On territorial
behaviour and other factors influencing habitat distri-
bution in birds. Acta Biotheorica 19:16-36.
Neu, C.W., C.R. Byers, andJ.M. Peek. 1974. A tech-
nique for analysis of utilization - availability data.
J. Wildl. Management 38:541-545.
Thomas, D.L. and E.J. Taylor. 1990. Study designs
and test for comparing resource use and availability.
J. Wildl. Management 54: 3322-3330.
Van Home, B. 1983. Density as a misleading indicator
of habitat quality. J. Wildl. Management
Vicente Berovides Alvarez',
Julio Ramos Reyes2, and Ledif Grisell Diaz Ramfrez'
' School of Biology, University of Havana
2 University of Pinar del Rio
V. Berovides: email@example.com
G. Diaz: firstname.lastname@example.org
Habitat Types N Mean Std. Dev. N Mean Std. Dev. N Mean Std. Dev.
Rinchospora 12 6.8' 4.4 12 5.2 b 3.7 12 16.6b 10.5
Batis 11 4.8b 3.1 6 0.7' 0.5 12 11.6b 7.5
Coast xeromorphic shrub 16 3.2b 2.1 16 10.3' 3.8 16 16.3b 11.5
Sandy coast vegetation 16 1.2' 1.7 - - - 16 28.0' 19.2
F (ANOVA) 20.4(p<0.001) 42.7 (p<0.001) 3.9 (p<0.05)
Table 1. Mean relative abundance of iguanas (N = number of sightings per 30 minutes), retreats, and fecal deposits on
Juan Garcfa Cay, San Felipe's Cays. a, b, c = means with significant differences, p< 0.05.
Mean# Mean# Mean#
Habitat Types Area (ha) % Cover eaon % Use Use/ Cover Oban % Use Use/ Cover Obeaons % Use Use / Cover
_abatpes___ _Observations _____ Observations _____ ______ Observations_____ _____
Rinchospora 11.1 16.0 10.7 40.2 2.51' 8.9 30 1.71' 27.7 20.9 1.30'
Batis 12.9 18.6 8.4 31.6 1.69' 1 3.4 0.16 20.5 15.5 0.83
Coast xeromorphic shrub 39.4 56.8 5.4 20.3 0.35 19.7 66.6 1.17 24.7 18.6 0.32
Sandy coast vegetation 6.0 8.6 2.1 7.9 0.92 - 59.7 45 5.23'
2- 18.8 (p < 0.001) 6.8 (p< 0.05) 241.3 (p < 0.001)
Table 2. Habitat selectivity by iguanas, including direct sightings, retreats, and fecal deposits, on Juan Garcia Cay, San Felipe's Cays.
Using Bonferroni's statistic: + = preferred habitat, - = non-preferred habitat, and 0 = habitat used proportionally.
Habitat Availabi t
Fecal De osits
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Published by the
Zoological Society of San Diego
Applied Conservation Division
15600 San Pasqual Valley Road,
Escondido, CA 92027
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Editors: e- " 4
Tandora Grant. . .
Allison Alberts t Z
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