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138 IGUANA  •  VOLUME 11, NUMBER 3  •  SEPTEMBER 2004 FOGARTY, ZERO, POWELL

Sint Eustatius, showing localities mentioned in the text. Illustration
by John Binns (modified from an original by John S. Parmerlee, Jr.).

Although some females were quite large, they usually retained some green color along their lower sides. Photograph by Robert Powell.

Adult female in a private garden on the lower leeward slope of
The Quill. Iguanas were abundant in this area, with each lushly
planted plot supporting at least 1–3 individuals. Animals were
not bothered by the sharp-edged leaves of the “Razor Plant.”
Photograph by Robert Powell.



The Lesser Antillean Iguana, Iguana delicatissima, is in trou-
ble. The species is listed in CITES Appendix I and as “vul-

nerable” in the most current IUCN Redlist. As for all island
species, especially those on small islands, populations are at con-
stant risk of extirpation. Islands of the Lesser Antilles, although
they can provide suitable habitat, are less than ideal for a large
animal on the brink of extinction. Most islands are small, which
inevitably leads to small population sizes and an increased risk of
extirpation due to natural or human-mediated, stochastic or non-
random events. Human population growth with accompanying
habitat destruction and alteration, introduction of alien preda-
tors and competitors, and ongoing hunting pressure all con-
tribute to the iguana’s plight.

The species’ original range, from Martinique in the south to
Anguilla in the north, is shrinking. Populations have been extir-
pated on Barbuda, Saint Kitts, Nevis, Antigua, Les Îles des
Saintes, Marie Galante, and St.-Martin/St. Maarten. Michel
Breuil recently listed the populations on Dominica, Îles de la
Petite Terre, and La Désirade as vulnerable; those on Basse-Terre,
Îlet Chancel (Martinique), and St.-Barthélemy as endangered;
and those on Antigua, Anguilla, Barbuda, Île Fourchue and satel-

Revisiting St. Eustatius:
Estimating the Population Size of Lesser
Antillean Iguanas, Iguana delicatissima

Sean P. Fogarty

Department of Biology, Harvey Mudd College, Claremont, California

Victoria H. Zero

Department of Biology, Reed College, Portland, Oregon

Robert Powell

Department of Biology, Avila University, Kansas City, Missouri

IGUANA  •  VOLUME 11, NUMBER 3  •  SEPTEMBER 2004 139REVISITING ST. EUSTATIUS

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Iguanas basking or resting in trees blended in well and were often dif-
ficult to see. Although large adults are relatively immune from preda-
tion, juveniles may be taken by large snakes (Alsophis rufiventris) or
birds-of-prey, such as Red-tailed Hawks (Buteo jamaicensis) or American
Kestrels (Falco sparvarius). Photograph by John S. Parmerlee, Jr.

View of Statia from Boven Hill: the rugged Northern Hills are in the
foreground, a portion of the Cultuurvlakte, the central plain, is visible,
and The Quill is in the background. Photograph by Sean P. Fogarty.



140 IGUANA  •  VOLUME 11, NUMBER 3  •  SEPTEMBER 2004 FOGARTY, ZERO, POWELL

An adult male in the Northern Hills, where iguanas were locally abundant, especially along forested ridges and in densely vegetated guts in this rel-
atively xeric area. Photograph by Sean P. Fogarty.

An adult female regularly spent the night in this Tamarind Tree. Here she awaits the early morning sun. Tamarind leaves were commonly eaten.
Photograph by Robert Powell.



IGUANA  •  VOLUME 11, NUMBER 3  •  SEPTEMBER 2004 141REVISITING ST. EUSTATIUS

lites (St.-Barthélemy), Grande-Terre, Martinique, St.-Martin, and
St. Eustatius as critically endangered — and those on Antigua,
Barbuda, and St.-Martin/St. Maarten have already disappeared.

Sint Eustatius, commonly known as Statia, is the northern-
most island on the St. Christopher (St. Kitts) Bank, which also
includes St. Kitts and Nevis. Within its 19.9 km2 live 2900 peo-
ple and about 8000 goats. The most noticeable feature of the
Statian landscape is The Quill, a 600-m tall dormant volcano in
the southeastern corner of the egg-shaped island. The Northern
Hills lie in the smaller end of the “egg” at the northwestern cor-
ner of the island. Although not especially tall, with Boven Hill
rising the highest at 289 m, these hills are characterized by steep
slopes and deep guts (gullies). Between The Quill and the
Northern Hills lies the Cultuurvlakte, the island’s central plain.
Vegetation on the island ranges from extremely dry scrub and
woodland in the northern hills to lush evergreen seasonal forest
inside the crater of The Quill.

In 2000, Steven Reichling published a report stating that
fewer than 300 iguanas remained on Statia when he visited in
November 1999. This followed a 1992 population estimate by
Mark Day and Brian Leysner stating that approximately 300 ani-
mals were on the island. We have no further information regard-
ing the methods used in the latter study. However, the apparent
population decline is similar to what has been seen on islands
elsewhere in the Lesser Antilles, where once abundant iguanas
have suffered from habitat encroachment, overhunting, compe-
tition for food with feral livestock (goats, cattle, and burros), and
predation by mongooses, rats, dogs, and cats. In addition, on at
least some islands, introduced Green Iguanas (Iguana iguana)
compete for habitat and food and, in some instances, have
hybridized with native I. delicatissima.

The 2004 Survey
In June 2004, we attempted to update the current status of the
species on Statia. While a density estimate was not the main
objective of our trip, it developed naturally from the behavioral
work in which we were already engaged. That research required
searching for both wild and human-habituated iguanas over
much of the island. Most of our work focused on three areas,
Gilboa Hill, the estates on the northwestern slope of The Quill,
and the cliffs above Smoke Alley Beach. In each of these areas, we
saw and recorded most of the iguanas present. We also saw ani-
mals on Boven Hill and on the western slope of The Quill.

Overall, we saw 33–37 different individuals on the island,
with about 22 of these in habitats not frequented by humans. We
spent 28–30 hours searching in the Northern Hills and approx-
imately 85 hours looking for snakes on The Quill. We also spent
approximately four hours looking for animals in landscaped gar-
dens around private residences (numbers of search hours are
rough estimates, since most of our time was spent observing
rather than searching for iguanas).

We estimated relative densities, as Reichling did, by calcu-
lating the hours searched per iguana seen. We also used the same
seven habitat zones described in his paper: Quill crater, outer
slopes of The Quill, foothill scrub around the base of The Quill,
Island Estates development, Cultuurvlakte (central plain),
foothills and guts bordering the Northern Hills, and the
Northern Hills themselves (Boven, Gilboa, Little Mountain,

Signal). The only time spent in the foothill scrub at the base of
The Quill and in the foothills and guts bordering the Northern
Hills was in transit to other areas. We saw no iguanas in either
area. Hours searched per iguana seen in other areas were:
Northern Hills — 1.8 (0.7 on Gilboa and 3.3 on Boven;
Reichling 2.75), Island Estates — 0.2 (Reichling 1.8), outer
slopes of The Quill — 8.3 (this is relatively high, but observers
in this area were not looking primarily for iguanas; Reichling
found none), and Cultuurvlakte — 0.4 (all along the cliffs above
Smoke Alley Beach; Reichling found none). Reichling found one
iguana per 7.3 search hours in the northern foothills and guts,
where we did not search. Note that all of our data are in hours
searched per individual iguana seen, not per sighting, as multiple
sightings of the same individual would have inflated our num-
bers (when in doubt regarding the identity of a given individual,
i.e., whether previously seen or not, we erred on the side of cau-
tion). However, our Cultuurvlakte and Island Estates encounter
rates are undoubtedly high, since we searched only in areas where
we knew that iguanas occurred.

Our sighting rates were much higher than we had antici-
pated from the data that Reichling had presented. Therefore, we
believed that an adjusted whole-island population estimate was
justified. In order to do this, we used the same habitat zones as
before. Our observations on Gilboa Hill were made in what we
designated “optimal” and “good” habitats. Based on similarities
in topography and vegetation, we identified “optimal” and
“good” and “other” habitats in the entire Northern Hills, for
which we calculated areas. We then extrapolated from our
encounter rates on Gilboa Hill to the entire Northern Hills,
resulting in a population estimate of 174–404 for that region of
the island.

During our visits to the grounds of three private residences
in the Island Estates area, we found three iguanas in each. By con-
servatively estimating that comparable numbers of individuals
lived in at least one- to two-thirds of the 63 estates in the area,
we estimated that approximately 63–126 animals occur in this
area.

We had to employ different techniques to estimate the pop-
ulation sizes in other areas, such as the outer slopes of The Quill,
the Smoke Alley cliffs, and sites at which locals indicated iguanas
were present. We assumed that population densities were lower
than in the Northern Hills because (1) Reichling saw no animals
on The Quill, (2) our encounter rates were relatively low (predi-
cated, at least in part, by the fact that most person-hours on The
Quill were by observers looking for terrestrial snakes along well-
established trails, rather than largely arboreal iguanas that may
well have been more common in areas far from the trails), and
(3) the degraded state of much of the understory vegetation,
attributable largely to the ubiquitous feral goats. However, the
area is extensive, includes considerable suitable habitat, and the
fact that individuals using a very different search image found
iguanas collectively suggest that a substantial population exists.
Based largely on our encounter rates and the proportion of the
total area of the slopes surveyed, we estimate that 30–60 iguanas
occupy the slopes of The Quill.

The Smoke Alley cliffs, above which the King’s Well Hotel
is located, are home to several individuals. At least five to seven
animals live on that portion of the slope behind the hotel, in



142 IGUANA  •  VOLUME 11, NUMBER 3  •  SEPTEMBER 2004 FOGARTY, ZERO, POWELL

This adult male was foraging for fallen fruit on the Smoke Alley cliffs. Unlike females, large males lose all traces of the green coloration typical of
juveniles. Photograph by John S. Parmerlee, Jr.

Even before exposure to direct sunlight, thermal images revealed that iguanas were considerably warmer than their environment. Photograph by
John S. Parmerlee, Jr.



IGUANA  •  VOLUME 11, NUMBER 3  •  SEPTEMBER 2004 143REVISITING ST. EUSTATIUS

what may be the highest density on the entire island. As many as
14 individuals were known to occur in that limited area until very
recently (within the past two years) and evidence of reproduction
exists in the form of juveniles observed at several locations as far
along the cliffs as the office of the St. Eustatius National Parks
Foundation (STENAPA) near the harbor. Based on actual obser-
vations and a crude assessment of habitat quality, a conservative
estimate of population size in this area is 10–50 individuals.

Other areas in which locals indicated that iguanas were pres-
ent and which had been cited in the literature as good iguana
habitat include the English Quarter, the nearby foothill scrub
habitat, and comparable habitat extending around The Quill to
the north and east. Because we did not search there and the habi-
tat is severely degraded, much of it overgrown with Mexican
Creeper (Antigonon sp.), we were uncomfortable counting any
iguanas in those areas, although isolated pockets of suitable habi-
tat probably support a few individuals.

When we combined all of our population estimates from
the areas listed, the worst- and best-case scenarios were 275 and
650, respectively. Very subjectively evaluating our assessments of
the island’s habitats and the current status of threats to the pop-
ulation, we believe that the most likely population size is about
425. Because we assumed that no iguanas occupied areas where
we were unable to confirm any individuals (notably those por-
tions of the Northern Hills we did not visit, the Quill crater, and
the lower slopes of The Quill, which include the English
Quarter), our numbers should be considered highly conservative.

That this estimate is nevertheless considerably higher than
Reichling’s estimate of fewer than 300 animals in 1999 is not sur-
prising. We saw half again as many animals while expending less
time and effort. Our estimate also exceeds Day and Leysner’s
1992 estimate of 300 individuals. This is good news, but could
it be an illusion?

Growing Population or Artifact?
The circumstantial evidence suggests that the apparent upturn in
the iguana population is real. First, locals in the Island Estates area
indicated to us that the number of sightings of iguanas crossing
roads has been growing in recent years. These areas are relatively
immune from iguana hunting, because much of the area consists
of large, gated properties. Also, animals that live on the grounds
of protected private residences are undoubtedly reproducing,
resulting in the repopulating of the adjacent Quill slopes. Second,
we found animals on the slopes of The Quill, where Reichling
saw none in either 1992 or 1999. Third, while he was unable to
find animals on the Smoke Alley cliffs in 1999, they are now rel-
atively abundant. The King’s Well Hotel, which had been hold-
ing and breeding animals at the time, released 14 animals some-
time after Reichling’s visit. These animals and their offspring
seem to be thriving. Fourth, when two of us initially went scout-
ing for iguanas in the Northern Hills, having never seen iguanas
in a natural setting, we found three iguanas in the first four hours
of searching! This was a far higher density than any of us had
expected, especially for inexperienced spotters. Finally, two other

Acclimated to humans, this female responded to the photographer’s presence only after a very close approach. Photograph by Robert Powell.



variables strongly suggest support for the higher numbers, the
incidence of hurricanes and an apparent decline in hunting pres-
sure.

Several long-time Statian residents independently com-
mented that iguanas become very difficult to find for periods of
up to several months after major hurricanes. They attributed this
to disruptions of habitats and defoliation of most plants that
would usually provide cover and food. The 1992 population
estimate was probably not affected by hurricanes, as three years
had passed since Hugo in 1989. However, hurricanes may have
dramatically affected the 1999 estimate. When Reichling made
his observations in November 1999, José, a category one hurri-
cane, had passed within 15 nautical miles in October and Lenny,
a category four, had passed within 29 nautical miles just days ear-
lier. In addition, Georges, a category 3 hurricane, had passed
within 14 nautical miles of Statia the year prior. The combined
effects of these hurricanes on the iguana population is difficult to
assess, but may well have been responsible for the decline in num-
bers between 1992 and 1999, and may account, at least in part,
for the apparent increase in the numbers of iguanas during the
hurricane-free years subsequent to Reichling’s visit.

Iguanas have been a source of food to islanders since
Amerindians first arrived on Statia. Even today, some men on the
island, particularly non-resident workers from other Caribbean
islands, apparently believe that eating iguana will enhance their

sexual energy. Also, Nicole Esteban, Director of STENAPA, still
receives occasional reports of iguana barbecues. However, based
on equally anecdotal evidence, the problem appears to be less per-
vasive than during the 1990s. At that time, long-term residents
reported that they routinely saw kids carrying iguanas to town in
an effort to acquire some spending money. Whether educational
efforts (see below) are paying off, more Statians are beginning to
understand the value of having iguanas on the island, or merely
because the availability of goods is better now, the potential ben-
efits of poaching iguanas seem to be diminishing.

Ongoing Conservation Concerns
The principal threat to Statia’s iguanas remains habitat alteration
and degradation. Although the human population is not grow-
ing rapidly, improvements in infrastructure and any new con-
struction, especially if they impinge on either the Northern Hills
or the slopes of The Quill, have the potential to reduce available
habitat. Of greater concern is the ongoing degradation of natu-
ral vegetation attributable to the spread of invasive alien species,
most notably the Mexican Creeper (Antigonon sp.), and to the
largely unchecked impact of feral herbivores. Goats, burros, and
even cattle are abundant, and range freely in even the most “nat-
ural” areas. Aggravating the problem is the fact that goats will eat
the Creeper only in the absence of other forage (iguanas are pre-
sumably just as discriminating). Ongoing efforts at the Botanical

144 IGUANA  •  VOLUME 11, NUMBER 3  •  SEPTEMBER 2004 FOGARTY, ZERO, POWELL

Iguanas were locally abundant along the Smoke Alley cliffs, where at
least some individuals were formerly held captive at the King’s Well
Hotel. Photograph by Robert Powell.

Shaded by The Quill and the cliffs, iguanas sleeping in trees often
remained in place until the mid-morning sun provided ample heat.
Photograph by Robert Powell.



Garden, situated on the windward eastern slope of The Quill,
dramatically illustrate the problem. Fences exclude goats but not
the Creeper, and, as the latter grows over the fences, its dense
growth provides access to the goats. Continually removing the
invasives is labor-intensive and unproductive in the long term.
Unless biological agents can be employed to reduce the incidence

of the Creeper and the goat population is either contained or dra-
matically reduced in size, iguanas will survive only in localized
pockets extremely vulnerable to exploitation or stochastic events.

The Quill and the Northern Hills have been designated
parts of Statia’s national park system, and consequently are
afforded some protection against development, if not against
goats and invasive plants. Because the promotion of ecotourism
to complement excellent offshore diving opportunities is the
most likely means of enhancing the nation’s economic growth,
reasonable hope exists that current disputes over ownership of the
Northern Hills and the problems created by too many goats will
eventually be resolved in favor of nature — and therefore the
iguanas, which themselves could serve as a tourist attraction. In
the immediate future, we can only hope that the situation does
not deteriorate so quickly that more enlightened policies can be
instituted and effectively enforced in time.

Predation by both humans and animals also remains a con-
cern. Although mongooses are not present on Statia, dogs and
cats are abundant. Both have been shown to cause declines in
iguana populations throughout the West Indies. Even if pets
remain, efforts to control feral predators should be employed.
Human predation appears to be declining, and ongoing educa-
tional efforts, largely by STENAPA, should have an increasingly
greater impact, as today’s students become involved in develop-
ing and implementing policies. Although iguana hunting is
already illegal and fines have been legislated, enforcement is essen-
tially nonexistent. Consequently, a complete cessation of hunt-

IGUANA  •  VOLUME 11, NUMBER 3  •  SEPTEMBER 2004 145REVISITING ST. EUSTATIUS

Goats are abundant and ubiquitous in even the most remote locations,
such as this hillside in the Northern Hills. They have dramatically
degraded the natural vegetation and often compete directly with igua-
nas for food. Photograph by Sean P. Fogarty.

This iguana (indicated by the arrow) seems to be seeking protection from the sign that had just been posted on the lower slopes of the Smoke Alley
cliffs. Fourteen of these signs were provided to the St. Eustatius National Parks Foundation by the IIS. Photograph by Victoria H. Zero.



ing activities will depend on widespread public support that
should increase, as students, who now benefit from environ-
mental programs in the schools, become actively engaged citizens.
Problems with guest workers from other islands, many of whom
see iguanas only as a resource to be exploited, will continue —
but should be more readily addressed if locals cease hunting ani-
mals and begin to view them as an economic asset.

Acknowledgements
Nicole Esteban and the staff, interns, and volunteers at STE-
NAPA were immensely helpful during our stay on Statia.
Heather Heinz (North Carolina State University), Trevor Joyce
(University of Alaska Southeast), Abigail Maley (Ohio Wesleyan
University), Aaron Savit (St. John’s College), and Robert
Henderson (Milwaukee Public Museum) all contributed field
observations. Fieldwork was funded by grant No. DBI-0242589
awarded by the National Science Foundation to Robert Powell.

References
Breuil, M. 2002. Histoire naturelle des amphibiens et reptiles terrestres de

l’Archipel Guadeloupéen. Guadaloupe, Saint-Martin, Saint-Barthélemy.
Patrimoines Naturels 54:1–339.

Reichling, S. 2000. The status of the Lesser Antillean Iguana on Sint Eustatius.
Iguana Times (J. Intl. Iguana Soc.) 8(1):3–6.

146 IGUANA  •  VOLUME 11, NUMBER 3  •  SEPTEMBER 2004 FOGARTY, ZERO, POWELL

This bright green juvenile basking in a palm tree above the Smoke Alley
cliffs is testament to successful recruitment. Photograph by Robert Powell.

Although primarily arboreal along the Smoke Alley cliffs, iguanas were not adverse to crossing open ground, even pausing to bask for short periods.
Photograph by Robert Powell.


